Caffeine psrformance on physical and cognitive performance Caffeine pills for improved performance sustained operations. Rivers and Webber, using themselves as subjects, imprived the performabce of caffeine on muscle fatigue. Similarly, Saunders et al. Consistent with this observation, the same study found individuals with the CC and TC genotypes appeared to confer greater sensitivity towards caffeine-induced sleep disturbance compared to the TT genotype [ ].

Caffeine pills for improved performance -

Inter-individual variation in caffeine ergogenicity, and a move towards personalised sports nutrition. Gu L, Gonzalez FJ, Kalow W, Tang BK. Biotransformation of caffeine, paraxanthine, theobromine and theophylline by cDNA-expressed human CYP1A2 and CYP2E1.

Sachse C, Brockmöller J, Bauer S, Roots I. Br J Clin Pharmacol. Womack CJ, Saunders MJ, Bechtel MK, et al. The influence of a CYP1A2 polymorphism on the ergogenic effects of caffeine. Guest N, Corey P, Vescovi J, El-Sohemy A. Caffeine, CYP1A2 genotype, and endurance performance in athletes. Med Sci Sport Exerc.

Pataky MW, Womack CJ, Saunders MJ, et al. Caffeine and 3-km cycling performance: effects of mouth rinsing, genotype, and time of day. Scand J Med Sci Sport. Algrain HA, Thomas RM, Carrillo AE, et al. The effects of a polymorphism in the cytochrome P CYP1A2 gene on performance enhancement with caffeine in recreational cyclists.

J Caffeine Res. Benowitz NL, Jacob P, Mayan H, Denaro C. Sympathomimetic effects of paraxanthine and caffeine in humans. Clin Pharmacol Ther. Orrú M, Guitart X, Karcz-Kubicha M, et al.

Psychostimulant pharmacological profile of paraxanthine, the main metabolite of caffeine in humans. Jeukendrup A, Saris WH, Brouns F, Kester AD.

A new validated endurance performance test. Med Sci Sports Exerc. Holland DT, Godfredsen KA, Page T, Connor JD. Simple high-performance liquid chromatography method for the simultaneous determination of serum caffeine and paraxanthine following rapid sample preparation. J Chromatogr B Biomed Sci Appl.

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Kovacs EMR, Stegen JHCH, Brouns F. Effect of caffeinated drinks on substrate metabolism, caffeine excretion, and performance.

Cox GR, Desbrow B, Montgomery PG, et al. Effect of different protocols of caffeine intake on metabolism and endurance performance. Vistisen K, Poulsen HE, Loft S. Foreign compound metabolism capacity in man measured from metabolites of dietary caffeine.

Ghotbi R, Christensen M, Roh H-K, Ingelman-Sundberg M, Aklillu E, Bertilsson L. Comparisons of CYP1A2 genetic polymorphisms, enzyme activity and the genotype-phenotype relationship in Swedes and Koreans.

Eur J Clin Pharmacol. Jiang Z, Dragin N, Jorge-Nebert LF, et al. Search for an association between the human CYP1A2 genotype and CYP1A2 metabolic phenotype. Pharmacogenet Genomics.

Kamimori GH, Karyekar CS, Otterstetter R, et al. The rate of absorption and relative bioavailability of caffeine administered in chewing gum versus capsules to normal healthy volunteers. Int J Pharm. Lelo A, Birkett D, Robson R, Miners J. Comparative pharmacokinetics of caffeine and its primary demethylated metabolites paraxanthine, theobromine and theophylline in man.

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J Sci Med Sport. de Gonçalves L. S, Painelli V de S, Yamaguchi G, et al. Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation. Caffeine withdrawal and high-intensity endurance cycling performance.

J Sports Sci. Grgic J, Grgic I, Pickering C, Schoenfeld BJ, Bishop DJ, Pedisic Z. Wake up and smell the coffee: caffeine supplementation and exercise performance - an umbrella review of 21 published meta-analyses. Br J Sports Med.

Burke LM, Peeling P. Methodologies for investigating performance changes with supplement use. Download references. Andrew D. Davenport, Tom S. Jameson, Sean P. Kilroe, Alistair J. Monteyne, George F. Pavis, Benjamin T. Wall, Marlou L. Beachbody, LLC, Exposition Blvd, Santa Monica, CA, , USA.

You can also search for this author in PubMed Google Scholar. AD, BW, NA, CM and FS conceived and designed the study. AD, TJ, SK, AM, GP and FS coordinated the study. AD and FS performed the analyses.

AD drafted the manuscript. All authors read and approved the final manuscript. Correspondence to Francis B. This study was approved by the Ethics Committee of the University of Exeter Sports and Health Science department and conforms to the Declaration of Helsinki. Prior to participation, written informed consent was obtained.

Francis B Stephens has received payments as a member of the Beachbody LLC scientific advisory board. Andrew D Davenport, Tom S O Jameson, Sean P Kilroe, Alistair J Monteyne, George F Pavis, Benjamin T Wall, Marlou L Dirks, Nima Alamdari and Catherine R Mikus have no competing interests to declare.

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Reprints and permissions. Davenport, A. et al. A Randomised, Placebo-Controlled, Crossover Study Investigating the Optimal Timing of a Caffeine-Containing Supplement for Exercise Performance. Sports Med - Open 6 , 17 Download citation.

Received : 29 October All products. Flavours No flavor. Package caps. Caffeine Capsules are extremely popular and for a good reason. They provide excellent value for money, not only because they are inexpansive, but also because they really work. Battery Caffeine could also contribute to improved performance and prevent fatigue.

Combined with the fact that Caffeine also contributes to enhanced mental alertness, Caffeine Tablets make a great choice as a pre-workout. Another advantage of caffeine in capsules is the accurate dosing that can be difficult to achieve with caffeine in powder.

Caffeine is a naturally occurring stimulant found in coffee, tea, guarana and other herbs. It also offers 10 mg of L-leucine. It is an essential amino acid that helps regulate blood sugar and helps the body repair muscle and bone. The company claims this caffeine supplement can support focus and provides long lasting energy without a crash.

The table below compares each product in this article for price, form, quantity, serving size, dosage, and more. Caffeine pills may be suitable for people looking for a convenient natural stimulant and energizer.

People may choose caffeine pills over other forms for several reasons. Some people may not enjoy foods or beverages containing caffeine, such as coffee or tea. Others might not like to consume energy drinks, coffee, and tea as they may contain extra ingredients or calories.

People may also be looking for a higher relative dose of caffeine without drinking multiple cups of coffee for the same effect. They may be sensitive to acidic drinks, such as coffee, which may irritate the digestive tract. A person can also combine caffeine pills with other ingredients to help enhance their stimulant effects.

This may make them a more effective option for people looking for a strong boost. Caffeine may be a useful substance as a fast-working natural stimulant. These effects are temporary. They only last as long as the caffeine remains in the body. The Food and Drug Administration FDA notes that caffeine consumption of up to milligrams mg per day is generally not associated with negative effects in healthy adults.

However, some people are more sensitive to caffeine than others. Each person will have a different tolerance level.

There are some risks associated with taking caffeine, particularly at high levels and in people sensitive to the substance.

Additionally, too much caffeine can overstimulate the body, causing side effects. Some adverse effects of caffeine, especially in high doses, include :.

The National Center for Complementary and Integrative Health NCCIH notes there is a link between heavy caffeine consumption and issues such as:. Large amounts of caffeine may also cause serious issues in the heart and blood vessels, including:. Children, teenagers, and young adults should avoid taking caffeine pills.

This drug may harm the developing nervous and cardiovascular systems in young people. Taking caffeine regularly and then suddenly discontinuing use may lead to temporary withdrawal symptoms, including :.

A caffeine overdose is possible in people who take very high doses of caffeine. Extremely high amounts of this drug are toxic and can even be fatal. Overdose symptoms include :.

Anyone experiencing symptoms of an overdose should seek immediate medical attention. Caffeine pills allow a person to take their preferred caffeine dose easily.

People should follow the dosage instructions on each product and monitor any side effects or symptoms they experience. People sensitive to the effects of caffeine pills may need to lower their dosage or switch to a weaker product. Do not take more than the recommended dose. Even in people with a high caffeine tolerance, other ingredients in the pills may cause adverse effects.

People should also be aware of any potential interactions between caffeine and prescription and nonprescription drugs. A review notes that varying levels of caffeine can affect the absorption and effectiveness of certain substances, such as selective serotonin reuptake inhibitors and iron-rich food or supplements.

MedlinePlus states that people should contact a healthcare professional before consuming caffeine if they take certain prescription medications, such as:. Even if product labels claim their pills derive from natural ingredients, they can still pose a risk when taken with other medications.

People should speak with a healthcare professional before using any supplements. According to the FDA, adults can generally consume up to mg of caffeine , or around 4—5 cups of coffee, per day without experiencing dangerous or negative side effects.

However, some people may be more sensitive to caffeine than others. Additionally, people who are trying to conceive, are pregnant , or are breastfeeding should contact a healthcare professional to discuss how much caffeine they can consume each day.

The FDA also warns that caffeine dietary supplements can be dangerous. Small amounts of pure or concentrated caffeine powder can lead to serious side effects and even death.

For example, half a cup of highly concentrated caffeine powder contains similar amounts of caffeine to 20 cups of coffee. One teaspoon of pure caffeine powder is equal to 28 cups of coffee. People should ensure that they carefully measure the amount of a supplement they consume and avoid pure or highly concentrated caffeine products that have the potential to cause harm.

Consuming too much caffeine can lead to serious side effects. The FDA has linked two deaths to pure and highly concentrated caffeine products in the United States. People should remember that natural or herbal caffeine alternatives are not risk-free. They could still trigger potentially harmful drug interactions in people with health conditions or people who take prescription medications.

Discuss these with a doctor before taking any caffeine supplements or alternatives. In addition, the FDA does not regulate these products. Buyers should make sure they choose products that have gone through independent laboratory testing to verify their purity and safety. Two potential alternatives to caffeine that can increase alertness are ginseng and maca.

Ginseng is an herb that people have used for over 2, years for various reasons, including as a stimulant. However, the NCCIH states that many studies investigating the effects of ginseng are of low quality, and more research is needed.

We include perforkance we think Caffeine pills for improved performance useful for our readers. Caffeine pills for improved performance you buy Cfafeine links on this page, we may earn a small perfromance. Medical News Today only shows you brands and products that we stand behind. Caffeine pills are a popular method for boosting short-term energy and focus, often during work or study. In moderate doses, these can be beneficial and safe to use. Like drinking a cup of coffeetaking a caffeine pill can provide a temporary boost in energy, memory, and focus.

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powder and natural e. guarana, kola nut forms. Synthetic caffeine is also an ingredient in several over-the-counter and prescription medications, as it is often used in combination with analgesic and diuretic drugs to amplify their pharmacological potency [ 21 ]. Additionally, there are varying levels of caffeine in the beans, leaves and fruit of more than 60 plants, resulting in great interest in herbal and other plant-based supplements [ 23 , 24 , 25 , 26 ].

Caffeine-containing energy drink consumption [ 27 , 28 , 29 , 30 , 31 ] and co-ingestion of caffeine with e. To date, the preponderance of caffeine and exercise performance literature has utilized anhydrous caffeine in a capsule [ 40 , 41 , 42 , 43 , 44 , 45 , 46 ] for simpler dose standardization and placebo creation.

A review of alternate caffeine forms may be found in the Alternative caffeine sources section and Tables 4 , 5 , 6 , 7 and 8. Anti-doping rules apply to most sports, especially in those where athletes are competing at national and international levels.

The IOC continues to recognize that caffeine is frequently used by athletes because of its reported performance-enhancing or ergogenic effects [ ]. Caffeine was added to the list of banned substances by the IOC in and the World Anti-Doping Agency WADA in The cut-off value was chosen to exclude typical amounts ingested as part of common dietary or social coffee drinking patterns, and to differentiate it from what was considered to be an aberrant use of caffeine for the purpose of sports performance enhancement [ ].

The highest use of caffeine was among endurance athletes in both studies [ , ]. Urinary caffeine concentration significantly increased from to in athletics, aquatics, rowing, boxing, judo, football, and weightlifting; however, the sports with the highest urine caffeine concentration in were cycling, athletics, and rowing [ ].

Caffeine or 1,3,7-trimethylxanthine, is an odorless white powder that is soluble in both water and lipids and has a bitter taste. It is rapidly absorbed from the gastrointestinal tract, mainly from the small intestine but also in the stomach [ ].

Caffeine is effectively distributed throughout the body by virtue of being sufficiently hydrophobic to allow easy passage through most, if not all biological membranes, including the blood-brain barrier [ ].

Once caffeine is absorbed, there appears to be no hepatic first-pass effect i. Caffeine absorption from food and beverages does not seem to be dependent on age, gender, genetics or disease, or the consumption of drugs, alcohol or nicotine. However, the rates of caffeine metabolism and breakdown appear to differ between individuals through both environmental and genetic influences [ 3 , , ].

The wide range of variability in caffeine metabolism is due to several factors. Several studies have also shown that the form of caffeine or its vehicle for entry into the body can modify the pharmacokinetics [ 58 , 81 , , ].

Liguori et al. The impact of temperature or rate of ingestion of caffeine has also been investigated, amidst concerns that cold energy drinks might pose a danger when chugged quickly, compared to sipping hot coffee. Similar to other caffeine pharmacokinetic studies [ , ], White et al.

energy drink may be associated with slight differences in pharmacokinetic activity, these differences are small. Chewing gum formulations appear to alter pharmacokinetics, as much of the caffeine released from the gum through mastication can be absorbed via the buccal cavity, which is considered faster due to its extensive vascularization, especially for low molecular weight hydrophobic agents [ ].

Kamimori et al. These pharmacokinetic findings are useful for military and sport purposes, where there is a requirement for rapid and maintained stimulation over specific periods of time.

Chewing gum may also be advantageous due to reduced digestive requirements, where absorption of caffeine in other forms capsule, coffee etc.

may be hindered by diminished splanchnic blood flow during moderate to intense exercise. Finally, there is a growing prevalence of caffeinated nasal and mouth aerosols administered directly in the mouth, under the tongue or inspired may affect the brain more quickly through several proposed mechanisms [ 5 ], although there are only a few studies to date to support this claim.

The administration of caffeine via aerosol into the oral cavity appears to produce a caffeine pharmacokinetic profile comparable to the administration of a caffeinated beverage [ 81 ].

Nasal and mouth aerosols will be discussed further in another section. Although the action of caffeine on the central nervous system CNS has been widely accepted as the primary mechanism by which caffeine alters performance, several mechanisms have been proposed to explain the ergogenic effects of caffeine, including increased myofibrillar calcium availability [ , ], optimized exercise metabolism and substrate availability [ 45 ], as well as stimulation of the CNS [ , , ].

One of the earlier proposed mechanisms associated with the ergogenic effects of caffeine stemmed from the observed adrenaline epinephrine -induced enhanced free-fatty acid FFA oxidation after caffeine ingestion and consequent glycogen sparing, resulting in improved endurance performance [ 18 , 45 , ].

However, this substrate-availability hypothesis was challenged and eventually dismissed, where after several performance studies it became clear that the increased levels of FFAs appeared to be higher earlier in exercise when increased demand for fuel via fat oxidation would be expected [ , , ].

Furthermore, this mechanism could not explain the ergogenic effects of caffeine in short duration, high-intensity exercise in which glycogen levels are not a limiting factor.

RER, changes in blood lactate, glucose , also appear to deliver measurable ergogenic effects, offering strong support for the CNS as the origin of reported improvements [ 43 , , ].

As such, focus has shifted to the action of caffeine during exercise within the central and peripheral nervous systems, which could alter the rate of perceived exertion RPE [ , , , ], muscle pain [ , , , ], and possibly the ability of skeletal muscle to generate force [ ].

Caffeine does appear to have some direct effects on muscle which may contribute to its ergogenicity. Caffeine appears to employ its effects at various locations in the body, but the most robust evidence suggests that the main target is the CNS, which is now widely accepted as the primary mechanism by which caffeine alters mental and physical performance [ ].

Caffeine is believed to exert its effects on the CNS via the antagonism of adenosine receptors, leading to increases in neurotransmitter release, motor unit firing rates, and pain suppression [ , , , , ].

There are four distinct adenosine receptors, A 1 , A 2A , A 2B and A 3 , that have been cloned and characterized in several species [ ]. Of these subtypes, A 1 and A 2A, which are highly concentrated in the brain, appear to be the main targets of caffeine [ ].

Adenosine is involved in numerous processes and pathways, and plays a crucial role as a homeostatic regulator and neuromodulator in the nervous system [ ]. The major known effects of adenosine are to decrease the concentration of many CNS neurotransmitters, including serotonin, dopamine, acetylcholine, norepinephrine and glutamate [ , , ].

Caffeine, which has a similar molecular structure to adenosine, binds to adenosine receptors after ingestion and therefore increases the concentration of these neurotransmitters [ , ].

This results in positive effects on mood, vigilance, focus, and alertness in most, but not all, individuals [ , ].

Researchers have also characterized aspects of adenosine A 2A receptor function related to cognitive processes [ ] and motivation [ , ]. In particular, several studies have focused on the functional significance of adenosine A 2A receptors and the interactions between adenosine and dopamine receptors, in relation to aspects of behavioral activation and effort-related processes [ , , , ].

The serotonin receptor 2A 5-HT2A has also been shown to modulate dopamine release, through mechanisms involving regulation of either dopamine synthesis or dopaminergic neuron firing rate [ , ].

Alterations in 5-HTR2A receptors may therefore affect dopamine release and upregulation of dopamine receptors [ , ]. This may therefore modulate dopamine activity, which may help to elucidate some of the relationships among neurotransmitters, genetic variation and caffeine response, and the subsequent impact on exercise performance.

Muscle pain has been shown to negatively affect motor unit recruitment and skeletal muscle force generation proportional to the subjective scores for pain intensity [ , ]. In one study, progressively increased muscle pain intensity caused a gradual decrease in motor firing rates [ ].

However, this decrease was not associated with a change in motor unit membrane properties demonstrating a central inhibitory motor control mechanism with effects correlated to nociceptive activity [ ]. Other studies also indicate that muscle force inhibition by muscle pain is centrally mediated [ ].

Accordingly, caffeine-mediated CNS mechanisms, such as dopamine release [ ], are likely imputable for pain mitigation during high-intensity exercise [ , , , , , , , ]. Although there appears to be strong evidence supporting the analgesic effects of caffeine during intense exercise, others have found no effect [ , ].

The attenuation of pain during exercise as a result of caffeine supplementation may also result in a decrease in the RPE during exercise. Two studies [ , ] have reported that improvements in performance were accompanied by a decrease in pain perception as well as a decrease in RPE under caffeine conditions, but it is unclear which factor may have contributed to the ergogenic effect.

Acute caffeine ingestion has been shown to alter RPE, where effort may be greater under caffeine conditions, yet it is not perceived as such [ 12 , , , ]. Others have not found changes in RPE with caffeine use [ ].

A more recent study by Green et al. The authors noted that individual responses to caffeine might explain their unexpected findings. In the last decade, our understanding of CNS fatigue has improved.

When caffeine and NECA were given together, the effects appeared to cancel each other out, and run time was similar to placebo. When the study was repeated with peripheral intraperitoneal body cavity injections instead of brain injections, there was no effect on run performance.

The authors concluded that caffeine increased running time by delaying fatigue through CNS effects, in part by blocking adenosine receptors [ ]. Caffeine also appears to enhance cognitive performance more in fatigued than well-rested subjects [ , , ].

This phenomenon is also apparent in exercise performance [ ] both in the field [ ] and in the lab [ 60 , 63 , ].

The placebo effect is a beneficial outcome that cannot be attributed to a treatment or intervention but is brought about by the belief that one has received a positive intervention. The nocebo effect is directly opposite to this in that a negative outcome occurs following the administration of an intervention or lack of an intervention e.

knowingly ingesting a placebo [ ]. For example, the nocebo may be a substance without medical effects, but which worsens the health status of the person taking it by the negative beliefs and expectations of the patient.

An example of this was reported in a study [ ] where well-trained cyclists exhibited a linear dose—response relationship in experimental trials from baseline to a moderate 4.

Athletes improved as the perceived caffeine doses increased; however, a placebo was used in all interventions. Similarly, Saunders et al. Therefore, readers are encouraged to consider whether studies that have explored the effects of caffeine on exercise have examined and reported the efficacy of the blinding of the participants.

At the highest level of sports, competitors will be near their genetic potential, will have trained intensively, followed prudent recovery protocols, and will have exploited all strategies to improve their performance—the use of an ergogenic aid, when legal, safe and effective, is an alluring opportunity.

Accordingly, caffeine is one of the most prominent ergogenic aids and is used by athletes and active individuals in a wide variety of sports and activities involving aerobic endurance. Caffeine has been shown to benefit several endurance-type sports including cycling [ 60 , , ], running [ 91 , , ] cross-country skiing [ ] and swimming [ ].

Much of the caffeine-exercise body of literature has focused on endurance-type exercise, as this is the area in which caffeine supplementation appears to be more commonly used and likely beneficial in most, but not all, athletes [ 11 , 12 , 13 ].

For example, the caffeine concentration in over twenty thousand urine samples obtained for doping control from to was measured after official national and international competitions [ , ].

A recent systematic review was carried out on randomised placebo-controlled studies investigating the effects of caffeine on endurance performance and a meta-analysis was conducted to determine the ergogenic effect of caffeine on endurance time-trial performance [ ].

Forty-six studies met the inclusion criteria and were included in the meta-analysis. Time-trial completion time showed improvements of 2.

However, there was some variability in outcomes with responses to caffeine ingestion, with two studies reporting slower time-trial performance, and five studies reporting lower mean power output during the time—trial [ ].

Dozens of endurance studies are highlighted through this review is various sections, showing consistent yet wide-ranging magnitudes of benefit for endurance performance under caffeine conditions. Strength and power development through resistance exercise is a significant component of conditioning programs for both fitness and competitive sport.

In resistance exercise, strength is most commonly assessed using 1 repetition maximum 1RM [ ], or different isometric and isokinetic strength tests [ ]. Although several studies exploring the effects of caffeine on strength performance have been published since the ISSN caffeine position stand [ 40 ], some uncertainty surrounding the benefits of caffeine in activities involving muscular endurance, strength and power remains.

Caffeine was shown to be ergogenic for muscular endurance in two meta-analyses reporting effect sizes ranging from 0. However, others have shown that it enhances strength but not muscular endurance [ , ], and when studies have examined multiple strength-muscular endurance tasks, there were benefits across the board [ 67 , ], none at all [ 98 , ], or even impairments in muscular endurance with caffeine use [ , ].

Ingesting caffeine prior to a muscular endurance task is likely to delay muscular fatigue, but these effects are not consistent among all studies. Three meta-analyses explored the acute effects of caffeine on strength, and all reported ergogenic effects [ , , ].

However, the effects in these meta-analyses were small, ranging from 0. Such small improvements in muscular strength likely have the greatest practical meaningfulness for athletes competing in strength-based sports, such as powerlifting and weightlifting athletes which already seem to be among the highest users of caffeine [ ].

Power output is also assessed during different protocols of intermittent-sprinting and repeated-sprints often with the Wingate cycling test as well as assessments during running [ ] or swimming repeated sprints [ ].

The data for repeated sprint and power performance using Wingate data has been mixed. In an older study, 10 male team-sport athletes performed 18, 4-s sprints with 2-min active recovery [ ].

A more recent study examining the effects of acute caffeine ingestion on upper and lower body Wingate performance in 22 males did not report significant findings when measuring lower body mean and peak power using the Wingate test [ ]. An older study by Greer et al. One meta-analysis reported that caffeine ingestion enhances mean and peak power during the Wingate test [ ], although the effect sizes of 0.

In contrast, another meta-analysis that examined the effects of caffeine on muscle power as assessed with the Wingate test for three of the studies, and repeated sprints for a maximum of s for the fourth, did not report benefits from ingestion of caffeine [ ].

An average caffeine dose of 6. A study by Lee et al. This might suggest that the rest interval between sprints may modulate the ergogenic effects of caffeine. Indeed, a recent meta-analysis that focused on the effects of caffeine on repeated-sprint performance reported that total work, best sprint, and last sprint performance was not affected by caffeine ingestion [ ].

Several studies have also shown substantial variability in outcomes. Similarly, Woolf et al. Ballistic movements such as throws and jumps are characterized by high motor unit firing rates, brief contraction times, and high rates of force development [ ].

Many studies have explored the effects of caffeine on jumping performance [ , ]. The body of evidence has indicated that caffeine supplementation increases vertical jump height during single and repeated jumps; however, the magnitude of these effects is rather modest, with effect sizes ranging from 0.

Besides jumping, several studies have explored the effects of caffeine on throwing performance. Overall, the current body of evidence indicates that caffeine supplementation may be useful for acute improvements in ballistic exercise performance in the form of jumps and throws.

However, more research is needed to explore the effects of caffeine on different throwing exercise tests, as this has been investigated only in a few studies. Generally, the primary sports-related goal of strength and power-oriented resistance training programs is to move the force-velocity curve to the right, indicating an ability of the athlete to lift greater loads at higher velocities [ ].

Several studies have explored the effects of caffeine on movement velocity and power in resistance exercise using measurement tools such as linear position transducers [ ].

These studies generally report that caffeine ingestion provides ergogenic effects of moderate to large magnitudes, with similar effects noted for both mean and peak velocity, and in upper and lower-body exercises [ 67 , , ].

Even though this area merits further research to fill gaps in the literature, the initial evidence supports caffeine as an effective ergogenic aid for enhancing velocity and power in resistance exercise. Even though caffeine ingestion may enhance performance in the laboratory, there has been a paucity of evidence to support that these improvements transfer directly to sport-specific performance.

To address this issue, several studies have also explored the effects of caffeine on sport-specific exercise tasks using sport simulation matches. Many studies conducted among athletes competing in team and individual sports, report that caffeine may enhance performance in a variety of sport tasks.

However, there are also several studies that report no effects as outlined below:. Basketball — increased jump height, but only in those with the AA version of the CYP1A2 gene [ ], increased number of free throws attempted and free throws made, increased number of total and offensive rebounds [ ], but did not improve sprint time [ ], nor dribbling speed [ ].

Volleyball — increased number of successful volleyball actions and decreased the number of imprecise actions [ , ], although caffeine did not improve physical performance in multiple sport-specific tests in professional females [ ], nor performance in volleyball competition [ ].

Football - did not improve performance for anaerobic exercise tests used at the NFL Combine [ ]. Rugby — increased the number of body impacts, running pace, and muscle power during jumping [ , ], but did not impact agility [ ].

Field hockey — increased high-intensity running and sprinting [ ], and may offset decrements in skilled performance associated with fatigue [ ]. Ice-hockey - has limited impact on sport-specific skill performance and RPE, but may enhance physicality during scrimmage [ ].

Combat sports — increased number of offensive actions and increased the number of throws [ ]. Cross-country skiing — reduced time to complete a set distance [ ] and improved time to task failure [ ]. In summary, although reviews of the literature show that caffeine ingestion is, on average , ergogenic for a wide range of sport-specific tasks, its use might not be appropriate for every athlete.

Specifically, the use of caffeine needs to be balanced with the associated side-effects and therefore experimentation is required in order to determine the individual response before assessing whether the benefits outweigh the costs for the athlete.

Athletes should gauge their physical response to caffeine during sport practice and competition in addition to monitoring mood state and potentially disrupted sleep patterns.

There is a lack of research examining potential interindividual differences in strength or anaerobic power-type exercise, but this is not the case for endurance exercise. In the myriad of studies examining caffeine on endurance performance, the benefits of caffeine do not appear to be influenced by sex, age, VO 2 max, type of sport, or the equivalent dose of caffeine [ 13 , , ].

Nevertheless, there appears to be substantial interindividual variability in response to caffeine under exercise conditions, which may be attributed to several factors outlined below. Genetic variants affect the way we absorb, metabolize, and utilize and excrete nutrients, and gene-diet interactions that affect metabolic pathways relevant to health and performance are now widely recognized [ ].

In the field of nutrigenomics, caffeine is the most widely researched compound with several randomized controlled trials investigating the modifying effects of genetic variation on exercise performance [ 75 , , , ]. Numerous studies have investigated the effect of supplemental caffeine on exercise performance, but there is considerable inter-individual variability in the magnitude of these effects [ 11 , 13 , 44 ] or in the lack of an effect [ , ], when compared to placebo.

Due to infrequent reporting of individual data it is difficult to determine the extent to which variation in responses may be occurring. The performance of some individuals is often in stark contrast to the average findings reported, which may conclude beneficial, detrimental, or no effect of caffeine on performance.

For example, Roelands et al. These inter-individual differences appear to be partly due to variations in genes such as CYP1A2 and possibly ADORA2A , which are associated with caffeine metabolism, sensitivity and response [ ].

In the general population, individuals with the AC or CC genotype slow metabolizers have an elevated risk of myocardial infarction [ ], hypertension and elevated blood pressure [ , ], and pre-diabetes [ ], with increasing caffeinated coffee consumption, whereas those with the AA genotype show no such risk.

Additionally, regular physical activity appears to attenuate the increase in blood pressure induced by caffeine ingestion, but only in individuals with the AA genotype [ ]. In that group, a 6. Among those with the CC genotype i. In those with the AC genotype there was no effect of either dose [ ].

The findings are consistent with a previous study [ ] that observed a caffeine-gene interaction indicating improved time trial cycling performance following caffeine consumption only in those with the AA genotype.

In contrast, previous studies either did not observe any impact of the CYP1A2 gene in caffeine-exercise studies [ , ], or reported benefits only in slow metabolizers [ 75 ]. There are several reasons that may explain discrepancies in study outcomes.

The effects of genotype on performance might be the most prominent during training or competition of longer duration or an accumulation of fatigue aerobic or muscular endurance [ ], where caffeine appears to provide its greatest benefits, and where the adverse effects to slow metabolizers are more likely to manifest [ , ].

Indeed, in a study of performance in elite basketball players [ ], only in those with the AA genotype caffeine improved repeated jumps which requires maintaining velocity at take-off repeatedly as an athlete fatigues throughout a game muscular endurance - even though there was no caffeine-genotype interaction effect for this outcome.

However, caffeine similarly improved performance in those with the both AA and C-genotypes during a simulated basketball game [ ].

In a cross-over design of 30 resistance-trained men, caffeine ingestion resulted in a higher number of repetitions in repeated sets of three different exercises, and for total repetitions in all resistance exercises combined, which resulted in a greater volume of work compared to placebo conditions, but only in those with the CYP1A2 AA genotype [ ].

Although more research is warranted, there is a growing body of evidence to support the role of CYP1A2 in modifying the effects of caffeine ingestion on aerobic or muscular endurance-type exercise, which helps to determine which athletes are most likely to benefit from caffeine.

The ADORA2A gene is another genetic modifier of the effects of caffeine on performance. The adenosine A 2A receptor, encoded by the ADORA2A gene, has been shown to regulate myocardial oxygen demand and increase coronary circulation by vasodilation [ , ]. The A 2A receptor is also expressed in the brain, where it has significant roles in the regulation of glutamate and dopamine release, with associated effects on insomnia and pain [ , ].

The antagonism of adenosine receptors after caffeine ingestion is modified by the ADORA2A gene, which may allow greater improvements in dopamine transmission and lead to norepinephrine and epinephrine release due to increased neuronal firing [ ] in some genotypes versus others.

Dopamine has been associated with motivation and effort in exercising individuals, and this may be the mechanism by which differences in response to caffeine are manifested [ , , ]. Currently, only one small pilot study has examined the effect of the ADORA2A gene rs on the ergogenic effects of caffeine under exercise conditions [ ].

Twelve female subjects underwent a double-blinded, crossover trial comprising two min cycling time trials following caffeine ingestion or placebo. Caffeine benefitted all six subjects with the TT genotype, but only one of the six C allele carriers.

Further studies are needed to confirm these preliminary findings and should include a large enough sample to distinguish any effects between the different C allele carriers i.

CT vs. CC genotypes and potential effects related to sex. The ADORA2A rs genotype has also been implicated, by both objective and subjective measures, in various parameters of sleep quality after caffeine ingestion in several studies [ , , , ]. Adenosine promotes sleep by binding to its receptors in the brain, mainly A 1 and A 2A receptors, and caffeine exerts an antagonist effect, blocking the receptor and reversing the effects of adenosine and promoting wakefulness [ ].

This action of caffeine may also serve athletes well under conditions of jetlag, and irregular or early training or competition schedules. Psychomotor speed relies on the ability to respond, rapidly and reliably, to randomly occurring stimuli which is a critical component of, and characteristic of, most sports [ ].

Genetic variation in ADORA2A has been shown to be a relevant determinant of psychomotor vigilance in the rested and sleep-deprived state and modulates individual responses to caffeine after sleep deprivation [ ].

Those with the CC genotype of ADORA2A rs consistently performed on a higher level on the sustained vigilant attention task than T-allele -carriers; however, this was tested in ADORA2A haplotypes that included combinations of 8 SNPs. This work provides the basis for future genetic studies of sleep using individual ADORA2A SNPs.

As mentioned, the ADORA2A genotype has also been implicated in sleep quality and increases in sleep disturbance [ ]. Increased beta activity in nonREM sleep may characterize individuals with insomnia when compared with healthy good sleepers [ ].

A functional relationship between the ADORA2A genotype and the effect of caffeine on EEG beta activity in nonREM sleep has previously been reported [ ], where the highest rise was in individuals with the CC genotype, approximately half in the CT genotype, whereas no change was present in the TT genotype.

Consistent with this observation, the same study found individuals with the CC and TC genotypes appeared to confer greater sensitivity towards caffeine-induced sleep disturbance compared to the TT genotype [ ]. This suggests that a common variant in ADORA2A contributes to subjective and objective responses to caffeine on sleep.

Given that anxiety may be normalized in elite sports even at clinical levels, factors that contribute to anxiety should be mitigated whenever possible. Anxiety may be caused by stress-related disorders burnout , poor quality sleep patterns often related to caffeine intakes and possibly as a response to caffeine ingestion due to genetic variation, even at low levels [ ].

As previously mentioned, caffeine blocks adenosine receptors, resulting in the stimulating effects of caffeine [ ]. A common variation in the ADORA2A adenosine A 2A receptor gene contributes to the differences in subjective feelings of anxiety after caffeine ingestion [ , ], especially in those who are habitually low caffeine consumers [ ].

This may be particularly relevant to athletes who possess the TT variant of rs in the ADORA2A gene. These individuals are likely to be more sensitive to the stimulating effects of caffeine and experience greater increases in feelings of anxiety after caffeine intake than do individuals with either the CT or CC variant [ , , ].

Sport psychologists commonly work with athletes to help them overcome anxiety about performance during competitions. Anxiety before or during athletic competitions can interfere not only in performance, but also in increased injury risk [ ].

Athletes who are more prone to performance anxiety may exacerbate their risk for feelings of anxiety depending on their caffeine use and which variant of the ADORA2A gene they possess.

Monitoring the actions of caffeine in those individuals who are susceptible, may alleviate some of the related feelings of anxiety with caffeine use. Given that anxiety may disrupt concentration and sleep and negatively impact social interactions, athletes with higher risks and prevalence for anxiety, may want to limit or avoid caffeine consumption if caffeine is a known trigger during times where they are feeling anxious or stressed, such as at sporting competitions or social gatherings or other work and school events.

The importance of both sleep and caffeine as an ergogenic aid to athletes highlights the importance of optimizing rest and recovery through a better understanding of which athletes may be at greater risk of adverse effects of caffeine on mood and sleep quality, possibly due to genetic variation.

This information will allow athletes and coaching staff to make informed decisions on when and if to use caffeine when proximity to sleep is a factor. These considerations will also be in conjunction with the possibility that an athlete will benefit from caffeine in endurance-based exercise as determined in part, by their CYP1A2 genotype, albeit with a clear need for future research.

The quantification of habitual caffeine intake is difficult, which is problematic for studies aiming to compare performance outcomes following caffeine ingestion in habitual versus non-habitual caffeine users.

This concern is highlighted by reports showing large variability in the caffeine content of commonly consumed beverages, e. Self-reported intakes may therefore be unreliable. Newly discovered biomarkers of coffee consumption may be more useful for quantifying intakes in the future, but currently, these are not widely available [ ].

Different protocols for the length of the caffeine abstinence period preceding data collection is also a relevant factor in determining variability in performance outcomes. For example, in shorter caffeine abstinence periods e.

alleviating the negative symptoms of withdrawal, which in itself may improve performance [ ]. These effects may be more pronounced in those genetically predisposed to severe withdrawal effects [ ].

Although genes have been associated with habitual caffeine intake using GWAS research [ , ], it is important to highlight that these associations are not directly applicable to determining differences in performance outcomes in response to acute caffeine doses for regular or habitual caffeine users versus non-habitual users.

Furthermore, associations between genes and habitual caffeine intake do not elucidate potential mechanisms by which caffeine intake behaviors may influence subsequent performance following caffeine supplementation [ , ]. In animal model studies, regular consumption of caffeine has been associated with an upregulation of the number of adenosine receptors in the vascular and neural tissues of the brain [ ].

Although, this did not appear to modify the effects of caffeine in one study [ ], in another, chronic caffeine ingestion by mice caused a marked reduction in locomotor exploratory activity [ ]. Changes in adenosine receptor number or activity have not been studied in humans.

There does not appear to be a consistent difference in the performance effects of acute caffeine ingestion between habitual and non-habitual caffeine users, and study findings remain equivocal.

In one study, habitual stimulation from caffeine resulted in a general dampening of the epinephrine response to both caffeine and exercise; however, there was no evidence that this impacted exercise performance [ ].

Four weeks of caffeine ingestion resulted in increased tolerance to acute caffeine supplementation in previously low habitual caffeine consumers, with the ergogenic effect of acute caffeine supplementation no longer apparent [ ].

Caffeine ingestion improved performance as compared to placebo and control, with no influence of habitual caffeine intake. However, a limitation of this study is the short h caffeine withdrawal period in all groups which may have resulted in performance improvements due to the reversal of caffeine withdrawal effects, rather than impact of acute-on-chronic caffeine administration and the effects of habituation to caffeine on exercise performance [ , ].

In addition, habitual caffeine intake was estimated using a food frequency questionnaire, which might be a limitation given the already mentioned variation of caffeine in coffee and different supplements.

There is wide variability in caffeine content of commonly consumed items, and as such, an objective measure e. Based on these observations, the assumption that habitual and nonhabitual caffeine consumers will or will not respond differently to caffeine supplementation during exercise, requires further study.

However, caffeine appears to be most beneficial during times or in sports where there is an accumulation of fatigue, i. A recent review [ ] reported that the effect size of caffeine benefits increase with the increasing duration of the time trial event, meaning that timing caffeine intake closer to a time of greater fatigue, i.

This supports the notion that endurance athletes with longer races may benefit most from caffeine for performance enhancement since they have the greatest likelihood of being fatigued.

This also supports findings in other investigations that show ingesting caffeine at various time points including late in exercise may be most beneficial [ ]. For example, an early study [ ] aimed to understand whether or not there were benefits to a common practice among endurance athletes, such as those participating in marathons and triathlons, which is to drink flat cola toward the end of an event.

When researchers investigated the ingestion of a low dose of caffeine toward the end of a race e. The study also demonstrated that the effect was due to the caffeine and not the carbohydrate, which may also aid performance as fuel stores become depleted [ ].

This may have been due to the faster absorption with caffeinated gum consumption, and due to the continued increase in plasma caffeine concentrations during the cycling time trial, when athletes may become fatigued i.

However, there was significant interindividual variability, highlighting the need for athletes to experiment with their own strategies as far as dosing and timing are concerned.

The optimal timing of caffeine ingestion may depend on the source of caffeine. As stated earlier, some of the alternate sources of caffeine such as caffeine chewing gums may absorb more quickly than caffeine ingested in caffeine-containing capsules [ 60 ].

Therefore, individuals interested in supplementing with caffeine should consider that timing of caffeine ingestion will likely be influenced by the source of caffeine. Currently, only a few investigations [ 96 , , , , , ] have included both trained and untrained subjects in their study design.

A limitation of this study is that the swimming exercise task differed between the trained and untrained participants. Specifically, the study utilized m swimming for the trained swimmers and m for the untrained swimmers, which is a likely explanation for these findings.

However, some have also postulated that this is because athletes perform more reliably on a given task than nonathletes, and increased test-retest reliability might prevent type II errors [ ]. In contrast to the above evidence regarding the importance of training status, other research has shown that training status does not moderate the ergogenic effects of caffeine on exercise performance.

One study [ ] showed similar performance improvements 1. Similarly, Astorino et al. More recently, a small study by Boyett et al. Subjects completed four experimental trials consisting of a 3-km cycling time trial performed in randomized order for each combination of time of day morning and evening and treatment.

They reported that both untrained and trained subjects improved performance with caffeine supplementation in the morning; however, only the untrained subjects improved when tested in the evening.

Although there were some limitations to this study, these observations indicate that trained athletes are more likely to experience ergogenic effects from caffeine in the morning, while untrained individuals appear to receive larger gains from caffeine in the evening than their trained counterparts.

This may further complicate the training status data with a possible temporal effect [ ]. The concentration of adenosine receptors the primary target of caffeine do appear to be higher in trained compared to untrained individuals, but this has only been reported in animal studies [ ].

Boyett et al. Although some studies comparing training status of subjects support the notion [ ] that training influences response to caffeine during exercise, most do not [ 96 , , ] and this was also the finding in a subsequent meta-analysis [ ]. It is possible that the only difference between trained and untrained individuals is that trained individuals likely have the mental discipline to exercise long or hard enough to benefit more from the caffeine stimulus, which might provide an explanation for why in some studies, trained individuals respond better to caffeine [ ].

Currently, it seems that trained and untrained individuals experience similar improvements in performance following caffeine ingestion; however, more research in this area is warranted.

The impacts of caffeine on sleep and behavior after sleep deprivation are widely reported [ ]. Sleep is recognized as an essential component of physiological and psychological recovery from, and preparation for, high-intensity training in athletes [ , ].

Chronic mild to moderate sleep deprivation in athletes, potentially attributed to caffeine intakes, may result in negative or altered impacts on glucose metabolism, neuroendocrine function, appetite, food intake and protein synthesis, as well as attention, learning and memory [ ].

Objective sleep measures using actigraphy or carried out in laboratory conditions with EEG have shown that caffeine negatively impacts several aspects of sleep quality such as: sleep latency time to fall asleep , WASO wake time after sleep onset , sleep efficiency and duration [ ].

Studies in athletes have also shown adverse effects in sleep quality and markers for exercise recovery after a variety of doses of caffeine ingestion [ , , ]. Although caffeine is associated with sleep disturbances, caffeine has also been shown to improve vigilance and reaction time and improved physical performance after sleep deprivation [ , , , , ].

This may be beneficial for athletes or those in the military who are traveling or involved in multiday operations, or sporting events and must perform at the highest level under sleep-deprived conditions [ , , , ].

Even though caffeine ingestion may hinder sleep quality, the time of day at which caffeine is ingested will likely determine the incidence of these negative effects. For example, in one study that included a sample size of 13 participants, ingestion of caffeine in the morning hours negatively affected sleep only in one participant [ ].

Unfortunately, athletes and those in the military are unlikely to be able to make adjustments to the timing of training, competition and military exercises or the ability to be combat ready. However, to help avoid negative effects on sleep, athletes may consider using caffeine earlier in the day whenever possible.

Pronounced individual differences have also been reported where functional genetic polymorphisms have been implicated in contributing to individual sensitivity to sleep disruption [ , ] and caffeine impacts after sleep deprivation [ ] as discussed in the Interindividual variation in response to caffeine: Genetics section of this paper.

As with any supplement, caffeine ingestion is also associated with certain side-effects. Some of the most commonly reported side-effects in the literature are tachycardia and heart palpitations, anxiety [ , ], headaches, as well as insomnia and hindered sleep quality [ , ].

For example, in one study, caffeine ingestion before an evening Super Rugby game resulted in a delay in time at sleep onset and a reduction in sleep duration on the night of the game [ ].

Caffeine ingestion is also associated with increased anxiety; therefore, its ingestion before competitions in athletes may exacerbate feelings of anxiety and negatively impact overall performance see caffeine and anxiety section. For example, athletes competing in sports that heavily rely on the skill component e.

However, athletes in sports that depend more on physical capabilities, such as strength and endurance e. These aspects are less explored in research but certainly warrant consideration in the practical context to optimize the response to caffeine supplementation.

The primary determinant in the incidence and severity of side-effects associated with caffeine ingestion is the dose used.

Side-effects with caffeine seem to increase linearly with the dose ingested [ ]. Therefore, they can be minimized—but likely not fully eliminated—by using smaller doses, as such doses are also found to be ergogenic and produce substantially fewer side-effects [ ].

In summary, an individual case-by-case basis approach is warranted when it comes to caffeine supplementation, as its potential to enhance performance benefit needs to be balanced with the side-effects risk.

In addition to exercise performance, caffeine has also been studied for its contribution to athletes of all types including Special Forces operators in the military who are routinely required to undergo periods of sustained cognitive function and vigilance due to their job requirements Table 1.

Hogervorst et al. They found that caffeine in a carbohydrate-containing performance bar significantly improved both endurance performance and complex cognitive ability during and after exercise [ 82 ]. Antonio et al. This matches a IOM report [ ] that the effects of caffeine supplementation include increased attention and vigilance, complex reaction time, and problem-solving and reasoning.

One confounding factor on cognitive effects of caffeine is the role of sleep. Special Forces military athletes conduct operations where sleep deprivation is common. A series of different experiments [ 42 , , , , , , , ] have examined the effects of caffeine in real-life military conditions.

In three of the studies [ , , ], soldiers performed a series of tasks such as a 4 or 6. The investigators found that vigilance was either maintained or enhanced under the caffeine conditions vs. placebo , in addition to improvements in run times and obstacle course completion [ , , ].

Similarly, Lieberman et al. Navy Seals. The positive effects of caffeine on cognitive function were further supported by work from Kamimori et al. The caffeine intervention maintained psychomotor speed, improved event detection, increased the number of correct responses to stimuli, and increased response speed during logical reasoning tests.

Under similar conditions of sleep deprivation, Tikuisis et al. When subjects are not sleep deprived, the effects of caffeine on cognition appear to be less effective. For example, Share et al.

In addition to the ability of caffeine to counteract the stress from sleep deprivation, it may also play a role in combatting other stressors. Gillingham et al. However, these benefits were not observed during more complex operations [ ]. Crowe et al.

Again, no cognitive benefit was observed. Other studies [ , , , ] support the effects of caffeine on the cognitive aspects of sport performance, even though with some mixed results [ , ]. Foskett et al. This was supported by Stuart et al. firefighting, military related tasks, wheelchair basketball [ ].

The exact mechanism of how caffeine enhances cognition in relation to exercise is not fully elucidated and appears to work through both peripheral and central neural effects [ ].

In a study by Lieberman et al. Repeated acquisition are behavioral tests in which subjects are required to learn new response sequences within each experimental session [ ]. The researchers [ 42 ] speculated that caffeine exerted its effects from an increased ability to sustain concentration, as opposed to an actual effect on working memory.

Other data [ ] were in agreement that caffeine reduced reaction times via an effect on perceptual-attentional processes not motor processes. This is in direct contrast to earlier work that cited primarily a motor effect [ ]. Another study with a sugar free energy drink showed similar improvements in reaction time in the caffeinated arm; however, they attributed it to parallel changes in cortical excitability at rest, prior, and after a non-fatiguing muscle contraction [ ].

The exact cognitive mechanism s of caffeine have yet to be elucidated. Based on some of the research cited above, it appears that caffeine is an effective ergogenic aid for individuals either involved in special force military units or who may routinely undergo stress including, but not limited to, extended periods of sleep deprivation.

Caffeine in these conditions has been shown to enhance cognitive parameters of concentration and alertness. It has been shown that caffeine may also benefit sport performance via enhanced passing accuracy and agility.

However, not all of the research is in agreement. It is unlikely that caffeine would be more effective than actually sleeping, i. Physical activity and exercise in extreme environments are of great interest as major sporting events e. Tour de France, Leadville , Badwater Ultramarathon are commonly held in extreme environmental conditions.

Events that take place in the heat or at high altitudes bring additional physiological challenges i. Nonetheless, caffeine is widely used by athletes as an ergogenic aid when exercising or performing in extreme environmental situations. Ely et al. Although caffeine may induce mild fluid loss, the majority of research has confirmed that caffeine consumption does not significantly impair hydration status, exacerbate dehydration, or jeopardize thermoregulation i.

Several trials have observed no benefit of acute caffeine ingestion on cycling and running performance in the heat Table 2 [ , , ]. It is well established that caffeine improves performance and perceived exertion during exercise at sea level [ , , , ].

Despite positive outcomes at sea level, minimal data exist on the ergogenic effects or side effects of caffeine in conditions of hypoxia, likely due to accessibility of this environment or the prohibitive costs of artificial methods. To date, only four investigations Table 3 have examined the effects of caffeine on exercise performance under hypoxic conditions [ , , , ].

Overall, results to date appear to support the beneficial effects of caffeine supplementation that may partly reduce the negative effects of hypoxia on the perception of effort and endurance performance [ , , , ]. Sources other than commonly consumed coffee and caffeine tablets have garnered interest, including caffeinated chewing gum, mouth rinses, aerosols, inspired powders, energy bars, energy gels and chews, among others.

While the pharmacokinetics [ 18 , , , , ] and effects of caffeine on performance when consumed in a traditional manner, such as coffee [ 47 , 49 , 55 , , , , ] or as a caffeine capsule with fluid [ 55 , , , ] are well understood, curiosity in alternate forms of delivery as outlined in pharmacokinetics section have emerged due to interest in the speed of delivery [ 81 ].

A recent review by Wickham and Spriet [ 5 ] provides an overview of the literature pertaining to caffeine use in exercise, in alternate forms. Therefore, here we only briefly summarize the current research. Several investigations have suggested that delivering caffeine in chewing gum form may speed the rate of caffeine delivery to the blood via absorption through the extremely vascular buccal cavity [ 58 , ].

Kamimori and colleagues [ 58 ] compared the rate of absorption and relative caffeine bioavailability from caffeinated chewing gum and caffeine in capsule form.

The results suggest that the rate of drug absorption from the gum formulation was significantly faster. These findings suggest that there may be an earlier onset of pharmacological effects from caffeine delivered through the gum formulation. Further, while no data exist to date, it has been suggested that increasing absorption via the buccal cavity may be preferential over oral delivery if consumed closer to or during exercise, as splanchnic blood flow is often reduced [ ], potentially slowing the rate of caffeine absorption.

To date, five studies [ 59 , 60 , 61 , 62 , 63 ] have examined the potential ergogenic impact of caffeinated chewing gum on aerobic performance, commonly administered in multiple sticks Table 4. To note, all studies have been conducted using cycling interventions, with the majority conducted in well-trained cyclists.

However, more research is needed, especially in physically active and recreationally training individuals. Four studies [ 64 , 66 , 68 , ] have examined the effect of caffeinated chewing gum on more anaerobic type activities Table 4. Specifically, Paton et al. The reduced fatigue in the caffeine trials equated to a 5.

Caffeinated gum consumption also positively influenced performance in two out of three soccer-specific Yo-Yo Intermittent Recovery Test and CMJ tests used in the assessment of performance in soccer players [ 66 ]. These results suggest that caffeine chewing gums may provide ergogenic effects across a wide range of exercise tasks.

To date, only Bellar et al. Future studies may consider comparing the effects of caffeine in chewing gums to caffeine ingested in capsules. Specifically, the mouth contains bitter taste sensory receptors that are sensitive to caffeine [ ].

It has been proposed that activation of these bitter taste receptors may activate neural pathways associated with information processing and reward within the brain [ , , ]. Physiologically, caffeinated mouth rinsing may also reduce gastrointestinal distress potential that may be caused when ingesting caffeine sources [ , ].

Few investigations on aerobic [ 69 , 74 , 75 , 76 , ] and anaerobic [ 72 , 73 , 78 ] changes in performance, as well as cognitive function [ 70 , 71 ] and performance [ 77 ], following CMR have been conducted to date Table 5.

One study [ ] demonstrated ergogenic benefits of CMR on aerobic performance, reporting significant increases in distance covered during a min arm crank time trial performance. With regard to anaerobic trials, other researchers [ 72 ] have also observed improved performance, where recreationally active males significantly improved their mean power output during repeated 6-s sprints after rinsing with a 1.

While CMR has demonstrated positive outcomes for cyclists, another study [ 78 ] in recreationally resistance-trained males did not report any significant differences in the total weight lifted by following a 1. CMR appears to be ergogenic in cycling to include both longer, lower-intensity and shorter high-intensity protocols.

The findings on the topic are equivocal likely because caffeine provided in this source does not increase caffeine plasma concentration and increases in plasma concentration are likely needed to experience an ergogenic effect of caffeine [ 69 ].

Details of these studies, as well as additional studies may be found in Table 5. The use of caffeinated nasal sprays and inspired powders are also of interest. Three mechanisms of action have been hypothesized for caffeinated nasal sprays.

Firstly, the nasal mucosa is permeable, making the nasal cavity a potential route for local and systemic substance delivery; particularly for caffeine, a small molecular compound [ 11 , 12 , 30 , 31 ].

Secondly, and similar to CMR, bitter taste receptors are located in the nasal cavity. The use of a nasal spray may allow for the upregulation of brain activity associated with reward and information processing [ ].

Thirdly, but often questioned due to its unknown time-course of action, caffeine could potentially be transported directly from the nasal cavity to the CNS, specifically the cerebrospinal fluid and brain by intracellular axonal transport through two specific neural pathways, the olfactory and trigeminal [ , ].

No significant improvements were reported in either anaerobic and aerobic performance outcome measures despite the increased activity of cingulate, insular, and sensory-motor cortices [ 79 ].

Laizure et al. Both were found to have similar bioavailability and comparable plasma concentrations with no differences in heart rate or blood pressure Table 6.

While caffeinated gels are frequently consumed by runners, cyclists and triathletes, plasma caffeine concentration studies have yet to be conducted and only three experimental trials have been reported. Cooper et al. In the study by Cooper et al. In contrast, Scott et al.

utilized a shorter time period from consumption to the start of the exercise i. However, these ideas are based on results from independent studies and therefore, future studies may consider exploring the optimal timing of caffeine gel ingestion in the same group of participants.

More details on these studies may be found in Table 7. Similar to caffeinated gels, no studies measured plasma caffeine concentration following caffeinated bar consumption; however, absorption and delivery likely mimic that of coffee or caffeine anhydrous capsule consumption.

While caffeinated bars are commonly found in the market, research on caffeinated bars is scarce. To date, only one study [ 82 ] Table 7 has examined the effects of a caffeine bar on exercise performance. Furthermore, cyclists significantly performed better on complex information processing tests following the time trial to exhaustion after caffeine bar consumption when compared to the carbohydrate only trial.

As there is not much data to draw from, future work on this source of caffeine is needed. A review by Trexler and Smith-Ryan comprehensively details research on caffeine and creatine co-ingestion [ 32 ]. With evidence to support the ergogenic benefits of both creatine and caffeine supplementation on human performance—via independent mechanisms—interest in concurrent ingestion is of great relevance for many athletes and exercising individuals [ 32 ].

While creatine and caffeine exist as independent supplements, a myriad of multi-ingredient supplements e. It has been reported that the often-positive ergogenic effect of acute caffeine ingestion prior to exercise is unaffected by creatine when a prior creatine loading protocol had been completed by participants [ , ].

However, there is some ambiguity with regard to the co-ingestion of caffeine during a creatine-loading phase e. While favorable data exist on muscular performance outcomes and adaptations in individuals utilizing multi-ingredient supplements e.

Until future investigations are available, it may be prudent to consume caffeine and creatine separately, or avoid high caffeine intakes when utilizing creatine for muscular benefits [ ].

This is likely due to the heterogeneity of experimental protocols that have been implemented and examined. Nonetheless, a systematic review and meta-analysis of 21 investigations [ ] concluded the co-ingestion of carbohydrate and caffeine significantly improved endurance performance when compared to carbohydrate alone.

However, it should be noted that the magnitude of the performance benefit that caffeine provides is less when added to carbohydrate i. carbohydrate than when isolated caffeine ingestion is compared to placebo [ ]. Since the publication [ ], results remain inconclusive, as investigations related to sport-type performance measures [ 83 , , , , , , ], as well as endurance performance [ 84 , , ] continue to be published.

Overall, to date it appears caffeine alone, or in conjunction with carbohydrate is a superior choice for improving performance, when compared to carbohydrate supplementation alone. Few studies to date have investigated the effect of post-exercise caffeine consumption on glucose metabolism [ , ].

While the delivery of exogenous carbohydrate can increase muscle glycogen alone, Pedersen et al. In addition, it has been demonstrated that co-ingestion of caffeine with carbohydrate after exercise improved subsequent high-intensity interval-running capacity compared with ingestion of carbohydrate alone.

This effect may be due to a high rate of post-exercise muscle glycogen resynthesis [ ]. Practically, caffeine ingestion in close proximity to sleep, coupled with the necessity to speed glycogen resynthesis, should be taken into consideration, as caffeine before bed may cause sleep disturbances.

The genus of coffee is Coffea , with the two most common species Coffea arabica arabica coffee and Coffea canephora robusta coffee used for global coffee production. While coffee is commonly ingested by exercising individuals as part of their habitual diet, coffee is also commonly consumed pre-exercise to improve energy levels, mood, and exercise performance [ 11 , 40 ].

Indeed, a recent review on coffee and endurance performance, reported that that coffee providing between 3 and 8. Specifically, Higgins et al. Since the release of the Higgins et al. review, three additional studies have been published, examining the effects of coffee on exercise performance.

Specifically, Niemen et al. Fifty-km cycling time performance and power did not differ between trials. Regarding resistance exercise performance, only two studies [ 55 , 56 ] have been conducted to date. One study [ 56 ] reported that coffee and caffeine anhydrous did not improve strength outcomes more than placebo supplementation.

On the other hand, Richardson et al. The results between studies differ likely because it is challenging to standardize the dose of caffeine in coffee as differences in coffee type and brewing method may alter caffeine content [ ].

Even though coffee may enhance performance, due to the difficulty of standardizing caffeine content most sport dietitians and nutritionists use anhydrous caffeine with their athletes due to the difficulty of standardizing caffeine content.

Consumption of energy drinks has become more common in the last decade, and several studies have examined the effectiveness of energy drinks as ergogenic aids Table 8.

Souza and colleagues [ ] completed a systematic review and meta-analysis of published studies that examined energy drink intake and physical performance. Studies including endurance exercise, muscular strength and endurance, sprinting and jumping, as well as sport-type activities were reviewed.

It has been suggested that the additional taurine to caffeine containing energy drinks or pre-workout supplements, as well as the addition of other ergogenic supplements such as beta-alanine, B-vitamins, and citrulline, may potentiate the effectiveness of caffeine containing beverages on athletic performance endeavors [ ].

However, other suggest that the ergogenic benefits of caffeine containing energy drinks is likely attributed to the caffeine content of the beverage [ ]. For a thorough review of energy drinks, consider Campbell et al. Table 8 provides a review of research related to energy drinks and pre-workout supplements.

Caffeine in its many forms is a ubiquitous substance frequently used in military, athletic and fitness populations which acutely enhance many aspects of exercise performance in most, but not all studies.

Supplementation with caffeine has been shown to acutely enhance many aspects of exercise, including prolonged aerobic-type activities and brief duration, high-intensity exercise.

The optimal timing of caffeine ingestion likely depends on the source of caffeine. Studies that present individual participant data commonly report substantial variation in caffeine ingestion responses.

Inter-individual differences may be associated with habitual caffeine intake, genetic variations, and supplementation protocols in a given study. Caffeine may be ergogenic for cognitive function, including attention and vigilance. Caffeine at the recommended doses does not appear significantly influence hydration, and the use of caffeine in conjunction with exercise in the heat and at altitude is also well supported.

Alternative sources of caffeine, such as caffeinated chewing gum, mouth rinses, and energy gels, have also been shown to improve performance. Energy drinks and pre-workouts containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.

Individuals should also be aware of the side-effects associated with caffeine ingestion, such as sleep disturbance and anxiety, which are often linearly dose-dependent.

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Caffeine synthase and related methyltransferases in plants. Caffeine supplements come in many forms, including pills, powders, and liquids. They're designed to provide a quick and convenient way to get a dose of caffeine without having to drink coffee or tea.

However, not all caffeine supplements are created equal. Some contain high amounts of caffeine, while others have additional ingredients that can affect their effectiveness. When looking for the best caffeine supplement, it's important to pay attention to the dosage and any additional ingredients.

Too much caffeine can cause jitters, anxiety, and other negative side effects, so it's important to choose a supplement with an appropriate dosage. Additionally, some supplements contain other ingredients like vitamins or herbs that can enhance the effects of caffeine or provide other benefits.

We spent hours researching and testing various caffeine supplements to identify the best options on the market.

In the following sections, we'll share our top picks and explain what makes them stand out from the rest. Our clinically-backed AI will ask you questions and provide an answer specific to your unique health situation.

We understand that sometimes you need a little extra boost to get through the day. That's why we've put together a list of the best caffeine supplements on the market to help keep you energized and focused. Whether you're an athlete looking for a pre-workout boost or a student studying for finals, these supplements can help you power through.

Check out our top picks below. Nutricost Caffeine Pills offer budget-friendly energy with mg per capsule, perfect for on-the-go lifestyles. However, users seeking complementary ingredients may be disappointed. Caution is advised for caffeine-sensitive individuals. Overall, an economical pick for straightforward energy needs.

If you're in search of a reliable caffeine supplement, Nutricost Caffeine Pills mg with capsules may be just what you need. This product offers a convenient and efficient way to boost your energy levels and enhance mental alertness. The cost-effectiveness of Nutricost Caffeine Pills, with its substantial quantity per bottle, is a standout feature for budget-conscious consumers.

The mg dosage per capsule provides flexibility in adjusting caffeine intake according to personal needs. Additionally, the convenience of capsules makes them an easy choice for individuals on the go.

However, it's worth noting that some users may miss the presence of additional ingredients that could complement or enhance the effects of caffeine. Furthermore, individuals sensitive to caffeine or those with specific health concerns should exercise caution and seek professional advice.

In conclusion, if you're in the market for a straightforward and economical caffeine supplement, Nutricost Caffeine Pills mg, Capsules could be a practical choice for your energy-boosting needs. We've been using this supplement for a while now, and we've found that it's a great alternative to sugary energy drinks and coffee.

The combination of l-theanine and caffeine helps us stay focused and alert, without the jitters that often come with other caffeine supplements. Plus, the addition of coconut MCT oil makes it easy to digest and absorb. One thing to keep in mind is that the dosage might be too low for some users.

Each liquid softgel provides mg of l-theanine and mg of organic caffeine, which might not be enough for those who need a higher dose. Additionally, if you're sensitive to caffeine, this supplement might not be the best choice for you.

It's a great option for those who want a clean source of energy and a boost in mental focus and alertness. Just be sure to start with the recommended dosage and monitor how your body reacts. We highly recommend the Genius Caffeine Pills for those in need of a sustained energy boost without the crash.

We were impressed with the Genius Caffeine Pills' ability to provide sustained energy and focus without the jittery feeling often associated with caffeine supplements. The VitaShure technology used in these pills delivers a burst of caffeine followed by a slow release to maintain consistent energy levels.

We found that taking one capsule in the morning as a replacement for coffee helped us stay alert and focused throughout the day. We also appreciated that the supplement is vegan and made without any unnecessary additives. However, we recommend being cautious when taking these pills later in the day, as they may lead to disrupted sleep if taken too close to bedtime.

Additionally, those sensitive to caffeine may want to start with a lower dosage or avoid this supplement altogether. Overall, we believe the Genius Caffeine Pills are a great option for those looking to supplement their energy and focus levels without the crash often associated with caffeine intake.

If you're looking for a natural and effective energy booster, SmarterVitamins Caffeine Supplement is a great choice. We tried SmarterVitamins Caffeine Supplement and were impressed with its ability to provide sustained energy and focus without the jittery feeling often associated with caffeine.

The addition of L-theanine helped to enhance our cognitive performance and improve our alertness. The all-natural ingredients and absence of harmful additives were also a plus, making us feel confident in our choice to use this supplement.

However, we did experience some mild jitters from the caffeine, so it may not be suitable for everyone. Overall, if you're looking for a natural and effective energy booster, SmarterVitamins Caffeine Supplement is definitely worth trying.

If you're looking for a caffeine supplement that can help you fight fatigue and increase mental focus, Natrol High Caffeine Tablets might be a good option. We found that Natrol High Caffeine Tablets delivered a noticeable surge of energy and helped us power through workouts and long workdays.

The tablets are easy to swallow and don't have a bitter taste like some other caffeine supplements we've tried.

However, we did experience some jitters and increased heart rate after taking the recommended dosage, so we would recommend starting with a lower dosage if you're sensitive to caffeine.

Additionally, we found that taking the tablets too late in the day disrupted our sleep, so we suggest taking them in the morning or early afternoon. Overall, if you're looking for a caffeine supplement that can help you power through your day, Natrol High Caffeine Tablets might be worth trying.

Just be sure to start with a lower dosage if you're sensitive to caffeine and avoid taking them too late in the day. We've had a positive experience with MuscleTech's caffeine pills, which have helped us power through long workdays and tough workouts. The pills provide a quick energy boost without the crash that can come from sugary energy drinks or coffee.

We appreciate that the pills are easy to take and convenient for on-the-go use. However, it's important to note that caffeine can cause jitters or anxiety in some people, so it's important to start with a small dose and see how your body reacts.

Additionally, taking caffeine too late in the day can lead to sleep disturbances, so it's important to use the product responsibly. Finally, customers should be aware that exposure to heat or sunlight may lead to melting or damage of the product, so it's important to be available during delivery.

Overall, we recommend MuscleTech's caffeine pills to anyone looking for a quick energy boost and increased mental focus. However, it's important to use the product responsibly and be aware of the potential side effects. We highly recommend BulkSupplements. com Caffeine Capsules for anyone looking for a caffeine supplement that provides an energy boost and helps with focus and productivity.

One of the best things about BulkSupplements. com Caffeine Capsules is that they provide a convenient and effective way to get an energy boost and stay focused throughout the day.

The mg of caffeine per capsule is equivalent to two cups of coffee, making it a great option for those who prefer not to drink coffee or who need a stronger boost. Another benefit of these caffeine capsules is that they are made with pure and clean ingredients and manufactured according to cGMP standards, ensuring maximum quality.

Third-party tests during production and packaging ensure that you get a high-quality product with each purchase. However, it's important to note that caffeine can cause jitters or anxiety in some people, and it's not suitable for those who are sensitive to caffeine.

Additionally, these capsules should not be taken in excess, as it can lead to negative side effects. In summary, if you're looking for a caffeine supplement that provides an energy boost and helps with focus and productivity, we highly recommend BulkSupplements.

com Caffeine Capsules. With 50mg of caffeine and mg of L-Theanine per capsule, this supplement provides a smart nootropic stack that supports energy, alertness, and clear focus.

The unflavored capsules are easy to take on the go, and the supplement contains no carbs, sugar, artificial flavors, or preservatives. It's also vegan, non-GMO, keto and paleo friendly, and proudly made in the USA in an eco-friendly facility under the latest cGMP guidelines.

It promotes energy day or night, so you can stay alert without the high jitters or caffeine crash from standard energy pills, chews, gum, or tablets. If you're looking for a natural caffeine supplement that provides sustained energy without jitters or crashes, you might want to try VitaMonk Low Dose Caffeine and Theanine.

We've been using VitaMonk Low Dose Caffeine and Theanine for a few weeks now, and we've noticed a significant improvement in our energy levels and concentration. The microdosing of caffeine and theanine provides a smooth energy boost that keeps us alert and focused throughout the day, without the usual side effects from other caffeine tablets like jitters or crashes.

We also appreciate that the low caffeine content won't disrupt our sleep patterns, and we can take them throughout the day for a slow-release caffeine effect. The natural ingredients are a big plus, with no artificial additives or fillers.

On the downside, the low caffeine content might not be enough for those who are used to higher doses of caffeine, and the effects might not be as strong as other caffeine supplements on the market.

Also, the product might not be suitable for those who are sensitive to caffeine.

Journal of the International Society of Sports Nutrition volume Caffeine pills for improved performance Coenzyme Q weight loss, Article number: 1 Cite Caffeine pills for improved performance article. Metrics Caffeinee. Following critical evaluation of the available literature to date, The International Caffwine of Ipmroved Nutrition ISSN position regarding caffeine intake is as follows:. Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions.

Journal of the Adaptogenic herbs for stress relief Society of Sports Nutrition pklls 18Article number: 1 Cite this Caffeine pills for improved performance. Metrics details. Following Caffsine evaluation of the available literature to date, Performanfe International Society of Sports Pervormance ISSN position regarding caffeine intake is as follows:.

Supplementation with Caffenie has Caffeine pills for improved performance shown to acutely Cafceine various aspects of exercise performance in many but not performancce studies.

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Aerobic endurance appears to be the form of exercise with Caffeeine most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals.

Very high doses of caffeine e. Optimal timing of Caffwine ingestion likely depends omproved the source Cafteine caffeine. For example, performznce compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption improevd the start of the exercise session.

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Caffeine may improve Low-carb weight loss and physical performance in some individuals under conditions of Caffiene deprivation. Alternative sources of caffeine ipmroved as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic Addiction treatment options. Energy drinks and pre-workout perfornance containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance.

Caffeine is ingested most frequently in the form of a beverage such as coffee, soft foor and tea, although the Caffeine pills for improved performance of many functional pipls, such as energy drinks, has been on a steady rise in the past Caffeine pills for improved performance decades [ 1 ].

Caffeine and its effects on health have been a longstanding topic of interest, and caffeine continues pilsl be a dietary compound of concern in perrormance health, as indicated by extensive investigations [ 7 Cffeine, 8910 ]. Pwrformance the same time, caffeine has become ubiquitous in perfornance sporting world, where there is keen Caffeinne in better understanding the impact of caffeine on various types of exercise performance.

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Cafceine of the earliest performanfe studies on caffeine came from two psychologists and Hypertension and caffeine consumption William Rivers and Harald Webber, at Pille University, who both Respiratory health statistics an interest in lmproved the piills and physiological oills of substances like caffeine improver alcohol.

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Significant research on impfoved effects perfogmance caffeine on exercise performance with gor subjects, different sports, and exploring variables such as the effects between trained and untrained individuals, began and continued through the s [ 1417 ].

However, strategies to improve wakefulness was the series of studies investigating the benefits Nutritional benefits of antioxidants caffeine in endurance sports in the Pillw Performance Pervormance at Pilos State Caffsine in the late s, led by David Costill [ 1819 ] and others [ 20 ], gor sparked a generation ppills research on the effects of caffeine in exercise metabolism and sports performance.

Along with naturally performacne sources, such as coffee, tea and cocoa, caffeine performabce also added to many foods, beverages and Caffelne products, such as jerky, improvev butter, and candy, in perforkance synthetic e.

perfirmance and natural e, Caffeine pills for improved performance. guarana, kola imporved forms. Synthetic caffeine is also an ingredient in fog over-the-counter and prescription Immune-boosting essential oils, as it is perfromance used in combination with analgesic and diuretic drugs to amplify their pharmacological potency polls 21 ].

Additionally, Caffeije are varying levels of caffeine Cafefine the beans, leaves and fruit performannce Caffeine pills for improved performance than Caffeine pills for improved performance plants, resulting in great interest in performancce and other plant-based supplements [ 23 improged, 2425pegformance ].

Caffeine-containing energy drink consumption Caffeije 27Proper hydration for sports293031 ] plls co-ingestion of caffeine with e. To date, the preponderance of caffeine and exercise performance literature has utilized anhydrous caffeine in a capsule [ 40414243444546 ] for simpler dose standardization and placebo creation.

A review of alternate caffeine forms may be found in the Alternative caffeine sources section and Tables 4567 and 8. Anti-doping rules apply to most sports, especially in those where athletes are competing at national and international levels.

The IOC continues to recognize that caffeine is frequently used by athletes because of its reported performance-enhancing or ergogenic effects [ ]. Caffeine was added to the list of banned substances by the IOC in and the World Anti-Doping Agency WADA in The cut-off value was chosen to exclude typical amounts ingested as part of common dietary or social coffee drinking patterns, and to differentiate it from what was considered to be an aberrant use of caffeine for the purpose of sports performance enhancement [ ].

The highest use of caffeine was among endurance athletes in both studies []. Urinary caffeine concentration significantly increased from to in athletics, aquatics, rowing, boxing, judo, football, and weightlifting; however, the sports with the highest urine caffeine concentration in were cycling, athletics, and rowing [ ].

Caffeine or 1,3,7-trimethylxanthine, is an odorless white powder that is soluble in both water and lipids and has a bitter taste.

It is rapidly absorbed from the gastrointestinal tract, mainly from the small intestine but also in the stomach [ ]. Caffeine is effectively distributed throughout the body by virtue of being sufficiently hydrophobic to allow easy passage through most, if not all biological membranes, including the blood-brain barrier [ ].

Once caffeine is absorbed, there appears to be no hepatic first-pass effect i. Caffeine absorption from food and beverages does not seem to be dependent on age, gender, genetics or disease, or the consumption of drugs, alcohol or nicotine.

However, the rates of caffeine metabolism and breakdown appear to differ between individuals through both environmental and genetic influences [ 3, ]. The wide range of variability in caffeine metabolism is due to several factors.

Several studies have also shown that the form of caffeine or its vehicle for entry into the body can modify the pharmacokinetics [ 5881, ]. Liguori et al. The impact of temperature or rate of ingestion of caffeine has also been investigated, amidst concerns that cold energy drinks might pose a danger when chugged quickly, compared to sipping hot coffee.

Similar to other caffeine pharmacokinetic studies [], White et al. energy drink may be associated with slight differences in pharmacokinetic activity, these differences are small.

Chewing gum formulations appear to alter pharmacokinetics, as much of the caffeine released from the gum through mastication can be absorbed via the buccal cavity, which is considered faster due to its extensive vascularization, especially for low molecular weight hydrophobic agents [ ].

Kamimori et al. These pharmacokinetic findings are useful for military and sport purposes, where there is a requirement for rapid and maintained stimulation over specific periods of time.

Chewing gum may also be advantageous due to reduced digestive requirements, where absorption of caffeine in other forms capsule, coffee etc. may be hindered by diminished splanchnic blood flow during moderate to intense exercise. Finally, there is a growing prevalence of caffeinated nasal and mouth aerosols administered directly in the mouth, under the tongue or inspired may affect the brain more quickly through several proposed mechanisms [ 5 ], although there are only a few studies to date to support this claim.

The administration of caffeine via aerosol into the oral cavity appears to produce a caffeine pharmacokinetic profile comparable to the administration of a caffeinated beverage [ 81 ].

Nasal and mouth aerosols will be discussed further in another section. Although the action of caffeine on the central nervous system CNS has been widely accepted as the primary mechanism by which caffeine alters performance, several mechanisms have been proposed to explain the ergogenic effects of caffeine, including increased myofibrillar calcium availability [], optimized exercise metabolism and substrate availability [ 45 ], as well as stimulation of the CNS [, ].

One of the earlier proposed mechanisms associated with the ergogenic effects of caffeine stemmed from the observed adrenaline epinephrine -induced enhanced free-fatty acid FFA oxidation after caffeine ingestion and consequent glycogen sparing, resulting in improved endurance performance [ 1845].

However, this substrate-availability hypothesis was challenged and eventually dismissed, where after several performance studies it became clear that the increased levels of FFAs appeared to be higher earlier in exercise when increased demand for fuel via fat oxidation would be expected [, ].

Furthermore, this mechanism could not explain the ergogenic effects of caffeine in short duration, high-intensity exercise in which glycogen levels are not a limiting factor. RER, changes in blood lactate, glucosealso appear to deliver measurable ergogenic effects, offering strong support for the CNS as the origin of reported improvements [ 43, ].

As such, focus has shifted to the action of caffeine during exercise within the central and peripheral nervous systems, which could alter the rate of perceived exertion RPE [,], muscle pain [,], and possibly the ability of skeletal muscle to generate force [ ].

Caffeine does appear to have some direct effects on muscle which may contribute to its ergogenicity. Caffeine appears to employ its effects at various locations in the body, but the most robust evidence suggests that the main target is the CNS, which is now widely accepted as the primary mechanism by which caffeine alters mental and physical performance [ ].

Caffeine is believed to exert its effects on the CNS via the antagonism of adenosine receptors, leading to increases in neurotransmitter release, motor unit firing rates, and pain suppression [, ].

There are four distinct adenosine receptors, A 1A 2AA 2B and A 3that have been cloned and characterized in several species [ ]. Of these subtypes, A 1 and A 2A, which are highly concentrated in the brain, appear to be the main targets of caffeine [ ].

Adenosine is involved in numerous processes and pathways, and plays a crucial role as a homeostatic regulator and neuromodulator in the nervous system [ ].

The major known effects of adenosine are to decrease the concentration of many CNS neurotransmitters, including serotonin, dopamine, acetylcholine, norepinephrine and glutamate [, ].

Caffeine, which has a similar molecular structure to adenosine, binds to adenosine receptors after ingestion and therefore increases the concentration of these neurotransmitters [].

This results in positive effects on mood, vigilance, focus, and alertness in most, but not all, individuals []. Researchers have also characterized aspects of adenosine A 2A receptor function related to cognitive processes [ ] and motivation [].

In particular, several studies have focused on the functional significance of adenosine A 2A receptors and the interactions between adenosine and dopamine receptors, in relation to aspects of behavioral activation and effort-related processes [,].

The serotonin receptor 2A 5-HT2A has also been shown to modulate dopamine release, through mechanisms involving regulation of either dopamine synthesis or dopaminergic neuron firing rate []. Alterations in 5-HTR2A receptors may therefore affect dopamine release and upregulation of dopamine receptors [].

This may therefore modulate dopamine activity, which may help to elucidate some of the relationships among neurotransmitters, genetic variation and caffeine response, and the subsequent impact on exercise performance.

Muscle pain has been shown to negatively affect motor unit recruitment and skeletal muscle force generation proportional to the subjective scores for pain intensity []. In one study, progressively increased muscle pain intensity caused a gradual decrease in motor firing rates [ ].

However, this decrease was not associated with a change in motor unit membrane properties demonstrating a central inhibitory motor control mechanism with effects correlated to nociceptive activity [ ].

Other studies also indicate that muscle force inhibition by muscle pain is centrally mediated [ ]. Accordingly, caffeine-mediated CNS mechanisms, such as dopamine release [ ], are likely imputable for pain mitigation during high-intensity exercise [,,].

Although there appears to be strong evidence supporting the analgesic effects of caffeine during intense exercise, others have found no effect []. The attenuation of pain during exercise as a result of caffeine supplementation may also result in a decrease in the RPE during exercise.

Two studies [] have reported that improvements in performance were accompanied by a decrease in pain perception as well as a decrease in RPE under caffeine conditions, but it is unclear which factor may have contributed to the ergogenic effect.

Acute caffeine ingestion has been shown to alter RPE, where effort may be greater under caffeine conditions, yet it is not perceived as such [ 12,]. Others have not found changes in RPE with caffeine use [ ]. A more recent study by Green et al. The authors noted that individual responses to caffeine might explain their unexpected findings.

In the last decade, our understanding of CNS fatigue has improved. When caffeine and NECA were given together, the effects appeared to cancel each other out, and run time was similar to placebo.

When the study was repeated with peripheral intraperitoneal body cavity injections instead of brain injections, there was no effect on run performance.

The authors concluded that caffeine increased running time by delaying fatigue through CNS effects, in part by blocking adenosine receptors [ ]. Caffeine also appears to enhance cognitive performance more in fatigued than well-rested subjects [, ]. This phenomenon is also apparent in exercise performance [ ] both in the field [ ] and in the lab [ 6063].

: Caffeine pills for improved performance

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Effects of caffeine chewing gum on race performance and physiology in male and female cyclists. J Sports Sci. Paton CD, Lowe T, Irvine A. Caffeinated chewing gum increases repeated sprint performance and augments increases in testosterone in competitive cyclists. Eur J Appl Physiol. Bellar DM, Kamimori G, Judge L, Barkley JE, Ryan EJ, Muller M, et al. Effects of low-dose caffeine supplementation on early morning performance in the standing shot put throw. Ranchordas MK, Pratt H, Parsons M, et al. Effect of caffeinated gum on a battery of rugby-specific tests in trained university-standard male rugby union players. Venier S, Grgic J, Mikulic P. Caffeinated gel ingestion enhances jump performance, muscle strength, and power in trained men. Acute enhancement of jump performance, muscle strength, and power in resistance-trained men after consumption of caffeinated chewing gum. Doering TM, Fell JW, Leveritt MD, Desbrow B, Shing CM. The effect of a caffeinated mouth-rinse on endurance cycling time-trial performance. De Pauw K, Roelands B, Knaepen K, Polfliet M, Stiens J, Meeusen R. Effects of caffeine and maltodextrin mouth rinsing on P, brain imaging, and cognitive performance. Article PubMed CAS Google Scholar. Pomportes L, Brisswalter J, Casini L, Hays A, Davranche K. Cognitive performance enhancement induced by caffeine, carbohydrate and guarana mouth rinsing during submaximal exercise. Beaven CM, Maulder P, Pooley A, Kilduff L, Cook C. Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance. Kizzi J, Sum A, Houston FE, Hayes LD. Influence of a caffeine mouth rinse on sprint cycling following glycogen depletion. Bottoms L, Hurst H, Scriven A, Lynch F, Bolton J, Vercoe L, Shone Z, Barry G, Sinclair J. The effect of caffeine mouth rinse on self-paced cyclingperformance. Com Ex Phys. Pataky MW, Womack CJ, Saunders MJ, Goffe JL, D'Lugos AC, El-Sohemy A, et al. Caffeine and 3-km cycling performance: effects of mouth rinsing, genotype, and time of day. Lesniak A, Davis SE, Moir GL, et al. The effects of carbohydrate, caffeine and combined rinses on cycling performance. J Sport Human Perform. Dolan P, Witherbee KE, Peterson KM, Kerksick CM. Clarke ND, Kornilios E, Richardson DL. Carbohydrate and caffeine mouth rinses do not affect maximum strength and muscular endurance performance. De Pauw K, Roelands B, Van Cutsem J, Marusic U, Torbeyns T, Meeusen R. Electro-physiological changes in the brain induced by caffeine or glucose nasal spray. De Pauw K, Roelands B, Van Cutsem J, Decroix L, Valente A, Taehee K, et al. Do glucose and caffeine nasal sprays influence exercise or cognitive performance? Laizure SC, Meibohm B, Nelson K, Chen F, Hu ZY, Parker RB. Comparison of caffeine disposition following administration by oral solution energy drink and inspired powder AeroShot in human subjects. Br J Clin Pharmacol. 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Improved cycling time-trial performance after ingestion of a caffeine energy drink. Sanders GJ, Peveler W, Holmer B, Peacock CA. The effect of three different energy drinks on oxygen consumption and perceived exertion during treadmillexercise. Al-Fares MN, Alsunni AA, Majeed F, Badar A. Effect of energy drink intake before exercise on indices of physical performance in untrained females. Saudi Med J. Prins PJ, Goss FL, Nagle EF, Beals K, Robertson RJ, Lovalekar MT, et al. Energy drinks improve five-kilometer running performance in recreational endurance runners. Kinsinger K, Oglesby B, Ojiambo R, Johann JM, Liguori G. Effects of 5-Hour ENERGY® Shot on Oxygen Consumption, Heart Rate, and SubstrateUtilization During Submaximal and Maximal Exercise. Int J Exerc Sci. Forbes SC, Candow DG, Little JP, Magnus C, Chilibeck PD. Effect of Red Bull energy drink on repeated Wingate cycle performance and bench-press muscle endurance. Del Coso J, Munoz-Fernandez VE, Munoz G, Fernandez-Elias VE, Ortega JF, Hamouti N, et al. Effects of a caffeine-containing energy drink on simulated soccer performance. Gonzalez AM, Walsh AL, Ratamess NA, Kang J, Hoffman JR. Effect of a pre-workout energy supplement on acute multi-joint resistance exercise. J Sports Sci Med. Astorino TACT, Lozano AT, Aburto-Pratt K, Duhon J. Ergogenic effects of caffeine on simulated time-trial performance are independent of fitness level. Campbell BI, Richmond JL, Dawes JJ. The effects of a commercial, pre-exercise energy drink supplement on power, muscular endurance, and repeated sprint speed. Eckerson JM, Bull AJ, Baechle TR, Fischer CA, O'Brien DC, Moore GA, et al. Acute ingestion of sugar-free red bull energy drink has no effect on upper body strength and muscular endurance in resistance trained men. Astley C, Souza DB, Polito MD. Acute Specific Effects of Caffeine-containing Energy Drink on Different Physical Performances in Resistance-trained Men. Magrini MA, Colquhoun RJ, Dawes JJ, Smith DB. Effects of a pre-workout energy drink supplement on upper body muscular endurance performance. Campbell BI, Kilpatrick M, Wilborn C, La Bounty P, Parker B, Gomez B, Elkins A, Williams S, dos Santos MG. A commercially available energy drinkdoes not improve peak power production on multiple second Wingate tests. Hoffman JR, Kang J, Ratamess NA, Hoffman MW, Tranchina CP, Faigenbaum AD. Examination of a pre-exercise, high energy supplement on exercise performance. Seidl R, Peyrl A, Nicham R, Hauser E. A taurine and caffeine-containing drink stimulates cognitive performance and well-being. Scholey AB, Kennedy DO. Smit HJ, Cotton JR, Hughes SC, Rogers PJ. Nutr Neurosci. Rao A, Hu H, Nobre AC. The effects of combined caffeine and glucose drinks on attention in the human brain. Howard MA, Marczinski CA. Acute effects of a glucose energy drink on behavioral control. Exp Clin Psychopharmacol. Wesnes KA, Brooker H, Watson AW, Bal W, Okello E. Effects of the Red Bull energy drink on cognitive function and mood in healthy young volunteers. J Psychopharmacol. Maughan RJ, Burke LM, Dvorak J, Larson-Meyer DE, Peeling P, Phillips SM, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Van Thuyne W, Delbeke FT. Distribution of caffeine levels in urine in different sports in relation to doping control before and after the removal of caffeine from the WADA doping list. Delbeke FT, Debackere M. Caffeine: use and abuse in sports. Spriet LL. Exercise and sport performance with low doses of caffeine. Caffeine and performance. Association TNCA. Del Coso J, Munoz G, Munoz-Guerra J. Prevalence of caffeine use in elite athletes following its removal from the World Anti-Doping Agency list of banned substances. Aguilar-Navarro M, Munoz G, Salinero JJ, Munoz-Guerra J, Fernandez-Alvarez M, Plata MDM, et al. Urine caffeine concentration in doping control samples from to Chvasta TE, Cooke AR. Emptying and absorption of caffeine from the human stomach. Callahan MM, Robertson RS, Arnaud MJ, Branfman AR, McComish MF, Yesair DW. Human metabolism of [1-methylC]- and [C] caffeine after oral administration. Drug Metab Dispos. Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet. Blanchard J, Sawers SJ. The absolute bioavailability of caffeine in man. Eur J Clin Pharmacol. White JR Jr, Padowski JM, Zhong Y, Chen G, Luo S, Lazarus P, et al. Pharmacokinetic analysis and comparison of caffeine administered rapidly or slowly in coffee chilled or hot versus chilled energy drink in healthy young adults. Clin Toxicol Phila. Mumford GK, Benowitz NL, Evans SM, Kaminski BJ, Preston KL, Sannerud CA, et al. Absorption rate of methylxanthines following capsules, cola and chocolate. Arnaud MJ. Metabolism of caffeine and other components of coffee. Caffeine, Coffee, and Health. New York: Raven Press; Tang-Liu DD, Williams RL, Riegelman S. Disposition of caffeine and its metabolites in man. J Pharmacol Exp Ther. Rasmussen BB, Brix TH, Kyvik KO, Brosen K. The interindividual differences in the 3-demthylation of caffeine alias CYP1A2 is determined by both genetic and environmental factors. Nelson DR, Zeldin DC, Hoffman SM, Maltais LJ, Wain HM, Nebert DW. Comparison of cytochrome P CYP genes from the mouse and human genomes, including nomenclature recommendations for genes, pseudogenes and alternative-splice variants. Begas E, Kouvaras E, Tsakalof A, Papakosta S, Asprodini EK. In vivo evaluation of CYP1A2, CYP2A6, NAT-2 and xanthine oxidase activities in a Greek population sample by the RP-HPLC monitoring of caffeine metabolic ratios. Biomed Chromatogr. Lelo A, Miners JO, Robson RA, Birkett DJ. Quantitative assessment of caffeine partial clearances in man. Thorn CF, Aklillu E, McDonagh EM, Klein TE, Altman RB. PharmGKB summary: caffeine pathway. Pharmacogenet Genomics. Mandel HG. Update on caffeine consumption, disposition and action. Djordjevic N, Ghotbi R, Jankovic S, Aklillu E. Ghotbi R, Christensen M, Roh HK, Ingelman-Sundberg M, Aklillu E, Bertilsson L. Comparisons of CYP1A2 genetic polymorphisms, enzyme activity and the genotype-phenotype relationship in Swedes and Koreans. Perera V, Gross AS, McLachlan AJ. Influence of environmental and genetic factors on CYP1A2 activity in individuals of South Asian and European ancestry. Clin Pharmacol Ther. Djordjevic N, Ghotbi R, Bertilsson L, Jankovic S, Aklillu E. Induction of CYP1A2 by heavy coffee consumption in Serbs and Swedes. Marks V, Kelly JF. Absorption of caffeine from tea, coffee, and coca cola. Liguori A, Hughes JR, Grass JA. Absorption and subjective effects of caffeine from coffee, cola and capsules. Pharmacol Biochem Behav. Shargel LYA. Applied biopharmaceutics and pharmacokinetics. Stamford: Appleton and Lange; Rousseau E, Ladine J, Liu QY, Meissner G. Arch Biochem Biophys. Tarnopolsky M, Cupido C. Caffeine potentiates low frequency skeletal muscle force in habitual and nonhabitual caffeine consumers. Kalmar JM, Cafarelli E. Caffeine: a valuable tool to study central fatigue in humans? Exerc Sport Sci Rev. Meeusen R, Roelands B, Spriet LL. Caffeine, exercise and the brain. Nestle Nutr Inst Workshop Ser. Nehlig A, Daval JL, Debry G. Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects. Brain Res Brain Res Rev. Chesley A, Howlett RA, Heigenhauser GJ, Hultman E, Spriet LL. Regulation of muscle glycogenolytic flux during intense aerobic exercise after caffeine ingestion. Graham TE, Helge JW, MacLean DA, Kiens B, Richter EA. Caffeine ingestion does not alter carbohydrate or fat metabolism in human skeletal muscle during exercise. Graham TE, Battram DS, Dela F, El-Sohemy A, Thong FS. Does caffeine alter muscle carbohydrate and fat metabolism during exercise? Tarnopolsky MA, Atkinson SA, MacDougall JD, Sale DG, Sutton JR. Physiological responses to caffeine during endurance running in habitual caffeine users. Casal DC, Leon AS. Failure of caffeine to affect substrate utilization during prolonged running. Glaister M, Gissane C. Caffeine and physiological responses to submaximal exercise: a meta-analysis. Talanian JL, Spriet LL. Low and moderate doses of caffeine late in exercise improve performance in trained cyclists. Cureton KJ, Warren GL, Millard-Stafford ML, Wingo JE, Trilk J, Buyckx M. Caffeinated sports drink: ergogenic effects and possible mechanisms. Black CD, Waddell DE, Gonglach AR. Caffeine's ergogenic effects on cycling: neuromuscular and perceptual factors. Killen LG, Green JM, O'Neal EK, McIntosh JR, Hornsby J, Coates TE. Effects of caffeine on session ratings of perceived exertion. Demura S, Yamada T, Terasawa N. Effect of coffee ingestion on physiological responses and ratings of perceived exertion during submaximal endurance exercise. Percept Mot Skills. Hadjicharalambous M, Georgiades E, Kilduff LP, Turner AP, Tsofliou F, Pitsiladis YP. Influence of caffeine on perception of effort, metabolism and exercise performance following a high-fat meal. Motl RW, O'Connor PJ, Tubandt L, Puetz T, Ely MR. Effect of caffeine on leg muscle pain during cycling exercise among females. Motl RW, O'Connor PJ, Dishman RK. Effect of caffeine on perceptions of leg muscle pain during moderate intensity cycling exercise. J Pain. Gliottoni RC, Meyers JR, Arngrimsson SA, Broglio SP, Motl RW. Effect of caffeine on quadriceps muscle pain during acute cycling exercise in low versus high caffeine consumers. Warren GL, Park ND, Maresca RD, McKibans KI, Millard-Stafford ML. Effect of caffeine ingestion on muscular strength and endurance: a meta-analysis. Allen DG, Lamb GD, Westerblad H. Impaired calcium release during fatigue. Lindinger MI, Graham TE, Spriet LL. Gonglach AR, Ade CJ, Bemben MG, Larson RD, Black CD. Muscle pain as a regulator of cycling intensity: effect of caffeine ingestion. Fredholm BB, Abbracchio MP, Burnstock G, Daly JW, Harden TK, Jacobson KA, et al. Nomenclature and classification of purinoceptors. Pharmacol Rev. Fredholm BB, Battig K, Holmen J, Nehlig A, Zvartau EE. Actions of caffeine in the brain with special reference to factors that contribute to its widespread use. Fredholm BB, Chen JF, Cunha RA, Svenningsson P, Vaugeois JM. Adenosine and brain function. Int Rev Neurobiol. Fredholm BB. Astra award lecture. Adenosine, adenosine receptors and the actions of caffeine. Pharmacol Toxicol. Meeusen R, Watson P, Hasegawa H, Roelands B, Piacentini MF. Central fatigue: the serotonin hypothesis and beyond. Nehlig A. Interindividual differences in caffeine metabolism and factors driving caffeine consumption. Salamone JD, Farrar AM, Font L, Patel V, Schlar DE, Nunes EJ, et al. Differential actions of adenosine A1 and A2A antagonists on the effort-related effects of dopamine D2 antagonism. Behav Brain Res. Salamone JD, Correa M, Ferrigno S, Yang JH, Rotolo RA, Presby RE. The psychopharmacology of effort-related decision making: dopamine, adenosine, and insights into the neurochemistry of motivation. Mingote S, Font L, Farrar AM, Vontell R, Worden LT, Stopper CM, et al. Nucleus accumbens adenosine A2A receptors regulate exertion of effort by acting on the ventral striatopallidal pathway. J Neurosci. Worden LT, Shahriari M, Farrar AM, Sink KS, Hockemeyer J, Muller CE, et al. The adenosine A2A antagonist MSX-3 reverses the effort-related effects of dopamine blockade: differential interaction with D1 and D2 family antagonists. Porras G, Di Matteo V, Fracasso C, Lucas G, De Deurwaerdere P, Caccia S, et al. Lucas G, De Deurwaerdere P, Caccia S, Umberto S. The effect of serotonergic agents on haloperidol-induced striatal dopamine release in vivo: opposite role of 5-HT 2A and 5-HT 2C receptor subtypes and significance of the haloperidol dose used. Di Giovanni G, Di Matteo V, Pierucci M, Esposito E. Serotonin-dopamine interaction: electrophysiological evidence. Prog Brain Res. Volkow ND, Wang GJ, Logan J, Alexoff D, Fowler JS, Thanos PK, et al. Transl Psychiatry. Zhang G, Stackman RW Jr. The role of serotonin 5-HT2A receptors in memory and cognition. Front Pharmacol. Abdolmaleky HM, Faraone SV, Glatt SJ, Tsuang MT. Meta-analysis of association between the TC polymorphism of the 5HT2a receptor gene and schizophrenia. Schizophr Res. Yamada S, Akita H, Kanazawa K, Ishida T, Hirata K, Ito K, et al. TC polymorphism of the serotonin 5-HT 2A receptor gene in patients with non-fatal acute myocardial infarction. Farina D, Arendt-Nielsen L, Merletti R, Graven-Nielsen T. Effect of experimental muscle pain on motor unit firing rate and conduction velocity. J Neurophysiol. Farina D, Arendt-Nielsen L, Graven-Nielsen T. Experimental muscle pain reduces initial motor unit discharge rates during sustained submaximal contractions. Graven-Nielsen T, Lund H, Arendt-Nielsen L, Danneskiold-Samsoe B, Bliddal H. Inhibition of maximal voluntary contraction force by experimental muscle pain: a centrally mediated mechanism. Muscle Nerve. Martikainen IK, Nuechterlein EB, Pecina M, Love TM, Cummiford CM, Green CR, et al. Chronic back pain is associated with alterations in dopamine neurotransmission in the ventral striatum. Duncan MJ, Oxford SW. Acute caffeine ingestion enhances performance and dampens muscle pain following resistance exercise to failure. J Sports Med Phys Fitness. Duncan MJ, Stanley M, Parkhouse N, Cook K, Smith M. Acute caffeine ingestion enhances strength performance and reduces perceived exertion and muscle pain perception during resistance exercise. Astorino TA, Cottrell T, Talhami Lozano A, Aburto-Pratt K, Duhon J. Physiol Behav. Maridakis V, O'Connor PJ, Dudley GA, McCully KK. Caffeine attenuates delayed-onset muscle pain and force loss following eccentric exercise. Astorino TA, Roupoli LR, Valdivieso BR. Caffeine does not alter RPE or pain perception during intense exercise in active women. Green JM, Olenick A, Eastep C, Winchester L. Caffeine influences cadence at lower but not higher intensity RPE-regulated cycling. Asmussen E. Muscle fatigue. Maclaren DP, Gibson H, Parry-Billings M, Edwards RH. A review of metabolic and physiological factors in fatigue. Davis JM, Zhao Z, Stock HS, Mehl KA, Buggy J, Hand GA. Central nervous system effects of caffeine and adenosine on fatigue. Am J Phys Regul Integr Comp Phys. Childs E, de Wit H. Enhanced mood and psychomotor performance by a caffeine-containing energy capsule in fatigued individuals. Lorist MM, Snel J, Kok A, Mulder G. Influence of caffeine on selective attention in well-rested and fatigued subjects. Vital-Lopez FG, Ramakrishnan S, Doty TJ, Balkin TJ, Reifman J. Caffeine dosing strategies to optimize alertness during sleep loss. J Sleep Res. Shen JG, Brooks MB, Cincotta J, Manjourides JD. Establishing a relationship between the effect of caffeine and duration of endurance athletic time trial events: a systematic review and meta-analysis. J Sci Med Sport. Cox GR, Desbrow B, Montgomery PG, Anderson ME, Bruce CR, Macrides TA, et al. Effect of different protocols of caffeine intake on metabolism and endurance performance. Clark VR, Hopkins WG, Hawley JA, Burke LM. Placebo effect of carbohydrate feedings during a km cycling time trial. Pollo A, Carlino E, Vase L, Benedetti F. Preventing motor training through nocebo suggestions. Foad AJ, Beedie CJ, Coleman DA. Pharmacological and psychological effects of caffeine ingestion in km cycling performance. Beedie CJ, Stuart EM, Coleman DA, Foad AJ. Placebo effects of caffeine on cycling performance. Saunders B, de Oliveira LF, da Silva RP, de Salles PV, Goncalves LS, Yamaguchi G, et al. Placebo in sports nutrition: a proof-of-principle study involvingcaffeine supplementation. Beedie CJ. Placebo effects in competitive sport: qualitative data. Christensen PM, Shirai Y, Ritz C, Nordsborg NB. By surrounding the mineral, the chelator protects it against degradation. Chelated nutrients are highly stable and may improve nutrient uptake and utilization. NutriGenesis ® is different from traditional nutrient forms: Bioengineered to be better. NutriGenesis ® are cultured nutrients that replicate the creation of vitamins, minerals and aminos in nature. NutriGenesis ® is based on the work of Nobel Prize-winning physiologist Albert Szent Gyorgy, who theorized that nutrients presented in their naturally grown forms supply cofactors that make them more bioavailable, biologically active and effective than nutrients that are isolated. In the NutriGenesis ® process, single-cell organisms are seeded with micronutrients in a hydroponic growth medium. As the cultures grow, they produce fresh new NutriGenesis ® vitamins, minerals and aminos within a matrix of natural cofactors. This familiar structure is more easily absorbed and utilized by the body. NutriGenesis ® advantages over other forms:. NutriGenesis ® is essentially food nutrition. Mirroring food nutrients molecule-by-molecule, our vitamins, minerals and aminos are presented in pure elemental form. Maximum nutrition: Nothing more, nothing less. Enhanced effectiveness. Because NutriGenesis ® nutrients are in food-matrix form, they are recognized by the body as nature-identical -- maximizing nutrient uptake, bioavailability and beneficial activity. Patented and researched. The patented process behind NutriGenesis ® has been shown in research to enhance nutrient absorption and retention when compared to chemical isolates. Cleaner and safer. NutriGenesis ® is produced in a sterile, tightly controlled lab setting. NutriGenesis ® is minimally processed, requiring no pesticides, herbicides or other synthetics associated with some other whole-food nutrients. Better for the planet: The NutriGenesis ® process is clean and efficient, with little carbon footprint or environmental impact - especially when compared to factory farming for phytonutrients and strip mining for minerals. It all begins with NutriGenesis ® Multi for Men and Multi for Women: This is Performance Lab ® 's multivitamin starting point for human performance optimization. NutriGenesis ® vitamins, minerals and amino acids are also found in multiple Performance Lab ® formulas. Beyond Performance Lab ® , NutriGenesis ® B-Vitamins are found in Mind Lab Pro ® - the world's most advanced brain supplement. Other Ingredients: NutriCaps ® Pullulan Capsule, Nu-FLOW ® Rice Concentrate. Suggested Use: Take 1 capsule for stimulation. Take up to 5 capsules daily, CONTAINS CAFFEINE - do not take more than 5 capsules in a hour period. For advanced usage guidelines visit www. createElement 'div' ; el. parse el. querySelector '[data-options]'. json ; }. error 'Error:', error ; } ; } }" quantity-changed1. Fast Shipping. error 'Error:', error ; } ; } }" quantity-changed2. error 'Error:', error ; } ; } }" quantity-changed3. Reviews 4. Dawn B Verified Customer. Read more. Produced to the highest quality clean label standards. To deliver the positive energy, clarity, and focus benefits of caffeine. No pointless ingredients. Pure and potent. Third-party tested and validated by Clean Label Project. With no downsides. For best results take capsule s on an empty stomach. Precisely dosed and blended with advanced nutrients. To deliver all the advantages of caffeine with none of the downsides. However, too much caffeine can lead to overstimulation that paradoxically worsens performance: To get the best performance benefits, individuals must determine their own optimal caffeine dose and manage caffeine intake accordingly. Amplified Alpha brain waves are associated with several cognitive benefits, including: Wakeful relaxation: A state of calm clarity without sedation Enhanced creativity and free-form cognitive exploration Reduced anxiety and improved mood balance In addition to raising Alpha brain waves, L-Theanine has been suggested to: Support dopamine, GABA and serotonin brain chemicals for a calm, motivated state of mind; Blunt excitatory brain chemicals to tone down an overstimulated central nervous system CNS ; Support blood pressure and heart rate in normal range, reflecting its overall CNS-relaxing effects. The all-natural ingredients and absence of harmful additives were also a plus, making us feel confident in our choice to use this supplement. However, we did experience some mild jitters from the caffeine, so it may not be suitable for everyone. Overall, if you're looking for a natural and effective energy booster, SmarterVitamins Caffeine Supplement is definitely worth trying. If you're looking for a caffeine supplement that can help you fight fatigue and increase mental focus, Natrol High Caffeine Tablets might be a good option. We found that Natrol High Caffeine Tablets delivered a noticeable surge of energy and helped us power through workouts and long workdays. The tablets are easy to swallow and don't have a bitter taste like some other caffeine supplements we've tried. However, we did experience some jitters and increased heart rate after taking the recommended dosage, so we would recommend starting with a lower dosage if you're sensitive to caffeine. Additionally, we found that taking the tablets too late in the day disrupted our sleep, so we suggest taking them in the morning or early afternoon. Overall, if you're looking for a caffeine supplement that can help you power through your day, Natrol High Caffeine Tablets might be worth trying. Just be sure to start with a lower dosage if you're sensitive to caffeine and avoid taking them too late in the day. We've had a positive experience with MuscleTech's caffeine pills, which have helped us power through long workdays and tough workouts. The pills provide a quick energy boost without the crash that can come from sugary energy drinks or coffee. We appreciate that the pills are easy to take and convenient for on-the-go use. However, it's important to note that caffeine can cause jitters or anxiety in some people, so it's important to start with a small dose and see how your body reacts. Additionally, taking caffeine too late in the day can lead to sleep disturbances, so it's important to use the product responsibly. Finally, customers should be aware that exposure to heat or sunlight may lead to melting or damage of the product, so it's important to be available during delivery. Overall, we recommend MuscleTech's caffeine pills to anyone looking for a quick energy boost and increased mental focus. However, it's important to use the product responsibly and be aware of the potential side effects. We highly recommend BulkSupplements. com Caffeine Capsules for anyone looking for a caffeine supplement that provides an energy boost and helps with focus and productivity. One of the best things about BulkSupplements. com Caffeine Capsules is that they provide a convenient and effective way to get an energy boost and stay focused throughout the day. The mg of caffeine per capsule is equivalent to two cups of coffee, making it a great option for those who prefer not to drink coffee or who need a stronger boost. Another benefit of these caffeine capsules is that they are made with pure and clean ingredients and manufactured according to cGMP standards, ensuring maximum quality. Third-party tests during production and packaging ensure that you get a high-quality product with each purchase. However, it's important to note that caffeine can cause jitters or anxiety in some people, and it's not suitable for those who are sensitive to caffeine. Additionally, these capsules should not be taken in excess, as it can lead to negative side effects. In summary, if you're looking for a caffeine supplement that provides an energy boost and helps with focus and productivity, we highly recommend BulkSupplements. com Caffeine Capsules. With 50mg of caffeine and mg of L-Theanine per capsule, this supplement provides a smart nootropic stack that supports energy, alertness, and clear focus. The unflavored capsules are easy to take on the go, and the supplement contains no carbs, sugar, artificial flavors, or preservatives. It's also vegan, non-GMO, keto and paleo friendly, and proudly made in the USA in an eco-friendly facility under the latest cGMP guidelines. It promotes energy day or night, so you can stay alert without the high jitters or caffeine crash from standard energy pills, chews, gum, or tablets. If you're looking for a natural caffeine supplement that provides sustained energy without jitters or crashes, you might want to try VitaMonk Low Dose Caffeine and Theanine. We've been using VitaMonk Low Dose Caffeine and Theanine for a few weeks now, and we've noticed a significant improvement in our energy levels and concentration. The microdosing of caffeine and theanine provides a smooth energy boost that keeps us alert and focused throughout the day, without the usual side effects from other caffeine tablets like jitters or crashes. We also appreciate that the low caffeine content won't disrupt our sleep patterns, and we can take them throughout the day for a slow-release caffeine effect. The natural ingredients are a big plus, with no artificial additives or fillers. On the downside, the low caffeine content might not be enough for those who are used to higher doses of caffeine, and the effects might not be as strong as other caffeine supplements on the market. Also, the product might not be suitable for those who are sensitive to caffeine. Overall, we recommend VitaMonk Low Dose Caffeine and Theanine for those who are looking for a natural caffeine supplement that provides sustained energy without jitters or crashes. When it comes to choosing the best caffeine supplement, there are several factors to consider. Here are some key features to look for when making your decision:. The first thing to consider is the dosage of caffeine in the supplement. It's important to choose a supplement that provides a safe and effective dose of caffeine. The recommended daily dose of caffeine is mg for healthy adults, but this can vary depending on factors such as age, weight, and tolerance. Be sure to check the label of any supplement you're considering to ensure that the dosage is appropriate for your needs. Caffeine supplements come in a variety of forms, including tablets, capsules, and powders. Each form has its own advantages and disadvantages. Tablets and capsules are convenient and easy to take, but they may take longer to absorb and may not be as effective as powders. Powders are faster-acting and more customizable, but they can be messy and may have a strong taste. Many caffeine supplements contain additional ingredients that can enhance their effects. For example, some supplements may contain L-theanine, an amino acid that can help reduce the jittery side effects of caffeine. Others may contain vitamins or minerals that can support overall health and energy levels. Be sure to read the label carefully to determine if any additional ingredients are included and if they are safe for you to take. Finally, it's important to choose a reputable brand when selecting a caffeine supplement. Look for brands that have a good track record of producing safe and effective supplements.
Caffeine Pills Safety, Risks, Tips	One confounding improevd on cognitive effects Caffeine pills for improved performance caffeine is the role of sleep. Indeed, supplementing with 1. Alternatives pilld for people who do not tolerate caffeine well. Caffeine is a fairly safe supplement at the recommended doses. The postulated correlations between variables in the reasoned pathway have been tested in several other PWM-related studies e.
CAFFEINE FOR PERFORMANCE	A person can also combine caffeine pills with other ingredients to help enhance their stimulant effects. This may make them a more effective option for people looking for a strong boost. Caffeine may be a useful substance as a fast-working natural stimulant. These effects are temporary. They only last as long as the caffeine remains in the body. The Food and Drug Administration FDA notes that caffeine consumption of up to milligrams mg per day is generally not associated with negative effects in healthy adults. However, some people are more sensitive to caffeine than others. Each person will have a different tolerance level. There are some risks associated with taking caffeine, particularly at high levels and in people sensitive to the substance. Additionally, too much caffeine can overstimulate the body, causing side effects. Some adverse effects of caffeine, especially in high doses, include :. The National Center for Complementary and Integrative Health NCCIH notes there is a link between heavy caffeine consumption and issues such as:. Large amounts of caffeine may also cause serious issues in the heart and blood vessels, including:. Children, teenagers, and young adults should avoid taking caffeine pills. This drug may harm the developing nervous and cardiovascular systems in young people. Taking caffeine regularly and then suddenly discontinuing use may lead to temporary withdrawal symptoms, including :. A caffeine overdose is possible in people who take very high doses of caffeine. Extremely high amounts of this drug are toxic and can even be fatal. Overdose symptoms include :. Anyone experiencing symptoms of an overdose should seek immediate medical attention. Caffeine pills allow a person to take their preferred caffeine dose easily. People should follow the dosage instructions on each product and monitor any side effects or symptoms they experience. People sensitive to the effects of caffeine pills may need to lower their dosage or switch to a weaker product. Do not take more than the recommended dose. Even in people with a high caffeine tolerance, other ingredients in the pills may cause adverse effects. People should also be aware of any potential interactions between caffeine and prescription and nonprescription drugs. A review notes that varying levels of caffeine can affect the absorption and effectiveness of certain substances, such as selective serotonin reuptake inhibitors and iron-rich food or supplements. MedlinePlus states that people should contact a healthcare professional before consuming caffeine if they take certain prescription medications, such as:. Even if product labels claim their pills derive from natural ingredients, they can still pose a risk when taken with other medications. People should speak with a healthcare professional before using any supplements. According to the FDA, adults can generally consume up to mg of caffeine , or around 4—5 cups of coffee, per day without experiencing dangerous or negative side effects. However, some people may be more sensitive to caffeine than others. Additionally, people who are trying to conceive, are pregnant , or are breastfeeding should contact a healthcare professional to discuss how much caffeine they can consume each day. The FDA also warns that caffeine dietary supplements can be dangerous. Small amounts of pure or concentrated caffeine powder can lead to serious side effects and even death. For example, half a cup of highly concentrated caffeine powder contains similar amounts of caffeine to 20 cups of coffee. One teaspoon of pure caffeine powder is equal to 28 cups of coffee. People should ensure that they carefully measure the amount of a supplement they consume and avoid pure or highly concentrated caffeine products that have the potential to cause harm. Consuming too much caffeine can lead to serious side effects. The FDA has linked two deaths to pure and highly concentrated caffeine products in the United States. People should remember that natural or herbal caffeine alternatives are not risk-free. They could still trigger potentially harmful drug interactions in people with health conditions or people who take prescription medications. Discuss these with a doctor before taking any caffeine supplements or alternatives. In addition, the FDA does not regulate these products. Buyers should make sure they choose products that have gone through independent laboratory testing to verify their purity and safety. Two potential alternatives to caffeine that can increase alertness are ginseng and maca. Ginseng is an herb that people have used for over 2, years for various reasons, including as a stimulant. However, the NCCIH states that many studies investigating the effects of ginseng are of low quality, and more research is needed. Maca may also be beneficial for people who are sensitive to caffeine or for those who are looking for an alternative. A study from suggests that maca may reduce tiredness. However, this research only investigated the effects of maca on people who have gone through menopause. In a animal study , maca improved physical fatigue in mice by strengthening muscle structures. However, these results have not been replicated in humans. As an alternative to drugs, people may benefit from the following to help them feel more awake and alert:. A person can consider discussing caffeine pills with a doctor if they are intending to take these on a regular basis. If a person develops any of the following side effects after taking caffeine pills, they should seek medical attention:. Most people can safely consume up to mg of caffeine per day. Caffeine pills may be healthier than getting caffeine from other sources, such as energy drinks, as they may not contain sugar or other added ingredients. Another study looked at whether consuming a high dose of caffeine improves muscle strength in male athletes who regularly drank coffee. Taking a high dose of caffeine did not significantly affect their maximum bench press strength compared with a placebo Overall, studies indicate that caffeine may provide benefits for power-based activities, but more research is needed to confirm this. Caffeine may help improve performance in strength or power-based exercises, but study results are mixed. Caffeine is a common ingredient in weight loss supplements. Caffeine also modestly increases your daily calorie expenditure One review of studies showed that consuming 1. However, no evidence suggests that caffeine consumption promotes significant weight loss. Caffeine can help release stored fat from fat cells, especially before and at the end of a workout. It can also help you burn more calories. If you regularly consume coffee, energy drinks, caffeinated soda, or dark chocolate , you may experience fewer benefits from caffeine supplements. This is because your body has developed a tolerance to caffeine Research suggests both caffeine anhydrous supplements and regular coffee provide benefits for exercise performance When supplementing with caffeine, the dose is often based on body weight, set at around 1. This is about — mg for most people, although some studies use up to — mg 1. Start at a low dose — around — mg — to assess your tolerance. Then increase the dose to or even mg to maintain a performance benefit. Very high doses — 4. If you wish to use caffeine for athletic performance, you should also save it for key events or races to maintain sensitivity to its effects. For optimal performance, take it about 60 minutes before a race or event. That said, the optimal timing may depend on the form of supplementation. For example, caffeinated chewing gums may be taken closer to the start of a race or event. Consuming — mg of caffeine 60 minutes before a race or event can help maximize performance benefits. At a sensible dose, caffeine can provide many benefits with few side effects. However, it may be unsuitable for some people. Here are some common side effects of too much caffeine :. High doses of mg — the amount in about 6 cups of coffee — have been shown to increase tremors and restlessness, especially for people who are not used to caffeine. People who are prone to anxiety may also want to avoid high doses Those with heart disease, high blood pressure, gastroesophageal reflux disease GERD , and several other conditions, as well as people who are pregnant, should use caution when consuming caffeine and consult their doctor to determine whether caffeine is safe for them. Timing may also matter, as late-night or evening caffeine can disrupt sleep. Try to avoid caffeine intake after 4 or 5 p. Finally, you could become ill, or even die, if you overdose on extremely high amounts of caffeine. Do not confuse milligrams with grams when using caffeine supplements. Caffeine is a fairly safe supplement at the recommended doses. It may cause minor side effects in some people and should be used with caution in individuals with heart disease, high blood pressure, GERD, and several other conditions. Caffeine is one of the most effective exercise supplements available. Studies have shown that caffeine can benefit endurance performance, high intensity exercise, and power sports. However, it seems to benefit trained athletes the most. Both caffeine anhydrous supplements and regular coffee provide performance benefits. Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available. VIEW ALL HISTORY. Caffeine has also been found to help promote weight loss, by stimulating the nervous system to mobilise fat from the fat tissues. The elevated adrenaline levels present in the body direct the fat tissues to break down fat and release it into the bloodstream. During a calorie deficit or negative energy balance, these fatty deposits can then be utilised as energy. Furthermore, research suggests that caffeine can increase your metabolic rate. This means it can increase how many calories your body burns, therefore promoting weight loss 5. Caffeine can reduce tiredness and fatigue, which are both often associated with increased risk of headaches and migraines. However, caffeine supplementation has also been suggested to change an individuals perception of pain. Therefore, caffeine is a key ingredient in many effective pain relief and headache and migraine treatments. One study demonstrating this effect used caffeine in conjunction with either paracetamol or aspirin. The amount of caffeine in a supplement varies by brand, though many contain between mg of caffeine per dose. Generally, it is not recommended to exceed mg of caffeine daily for healthy adults. Consuming too much caffeine can increase risk of uncomfortable and sometimes dangerous side effects. If you are consuming other caffeine-containing products, such as tea, coffee or energy drinks, it is recommended to hold off on caffeine supplements. Consuming up to mg of caffeine per day is safe for healthy adults. However, as with many stimulants, there is a risk of becoming dependent on caffeine if it is not ingested in moderation or according to safety guidelines. Withdrawal can then become difficult, as symptoms such as dizziness, fatigue and anxiety may be present. In comparison to pure caffeine powder or liquid, caffeine tablets provide a more accurate and reliable method of supplementation. Caffeine powder is a highly potent substance that can be very dangerous in use, as it is more difficult to measure precise amounts. With overdose, this can lead to toxic effects, and may be life-threatening. To stay safe, monitor your caffeine intake from natural sources and adhere to the safety guidelines on your supplement packaging. Use a tablet or gummy rather than pure powder form, and avoid over-the-counter medications containing caffeine, unless cleared by your doctor. Finally, be observant of side effects and seek medical attention if they become distressing. It is important to keep yourself safe while aiming to obtain maximum benefit from your caffeine supplement. To do this, and reduce the risk of side effects, here is how we recommend taking your supplement:. Myvitamins are not making any medical claims within this article. If you are interested in supplementing with caffeine, speak to your GP to discuss the benefits and safety in your unique case. Caffeine supplements stimulate the central nervous system to provide a wide array of benefits. This can include improving athletic performance, increased focus and concentration, providing support to maintain a healthy weight, and relief for headaches and migraines. Caffeine supplements are safe to consume when done so according to guidelines, and within the healthy range of daily caffeine intake. However, overdose may lead to unpleasant side effects. If you are looking to boost your performance at work or during exercise, consider implementing a caffeine supplement into your routine. Caffeine supplements stimulate the central nervous system to provide a range of effects such as improving focus, memory, athletic performance, and reducing feelings of fatigue.

Fod pills may be an flr way to get a buzz but beware Cffeine the side effects. Caffeine is a Caffeine pills for improved performance High-quality dietary fats acts flr Caffeine pills for improved performance central nervous system—nerves, brain, and spinal cord—to make you feel more awake and alert. When you need energy to get through the day, you may use different caffeine sources like coffee and energy drinks. However, another caffeine option is caffeine pills or tablets. Caffeine pills can be safe when used according to package directions and healthcare provider consultation.