Hydration and sports performance metrics -
Therefore, the purpose of this review is to provide a practical summary of the potential methods of assessing hydration, their limitations and recommendations for best practice with a focus on athletic populations.
Such a review will be useful for practitioners or researchers who are trying to navigate the complicated topic and make practical and well-informed decisions. Due to the range of topics explored within this review and the many methods used practically within the field, we elected to take the approach of a narrative review as opposed to a systematic review or meta-analysis which would use a highly technical, specific methodological approach to identify and appraise evidence on hydration assessment [ 16 ].
While there are strengths to the systematic approach, a narrative approach allowed for a more flexible structure to provide clarification and nuanced insight into hydration testing with an interpretive and discursive synthesis of the existing literature. Consequently, this narrative appraisal of the literature allows for an interpretive overview, providing reflection and context rather than a formal objective appraisal of hydration testing practices in the constraints of rigidly defined inclusion and exclusion criteria.
Additionally, the reference lists of found papers were searched to find any additional sources. Defining hydration is difficult as the function and storage of fluid throughout the body is complicated.
However, water is stored in many different compartments not only the intracellular, interstitial, and plasma spaces, but also the gastrointestinal tract and bladder [ 2 , 13 ] and the location of fluid will influence its function e. fluid in the bladder cannot be used for sweating.
Fluid located within the interstitial spaces is involved in many vital process at both rest and during exercise [ 5 ], likewise cellular fluid volume is critical to cell function and should be a focus when assessing hydration status.
It is also important to consider whether the goal is to get a single assessment of hydration status or assess changes over time, as a single measure can be approached differently than assessing changes over time.
Changes in total body water TBW will not always apply equally to every compartment of fluid throughout the body [ 2 ]. This is especially the case for shifts in body position [ 17 ], during exercise [ 5 ], or during dehydration and rehydration [ 7 ].
For example, exercise causes fluid shifts between different compartments, thus complicating subsequent assessments [ 14 ]. The range of potential confounders when assessing hydration makes it essential for appropriate standardisation protocols to be followed [ 18 ].
Meaningful assessment of hydration status is more difficult than simply assessing changes in TBW. Many assessments involve measuring fluid in specific locations such as urine [ 19 ], blood [ 18 ], tears [ 20 ] or saliva [ 21 ], which then provides contrasting information regarding hydration status.
Consequently, the location of fluid being assessed is important for informing the methods utilised and interpretations made. Whole blood is essential to many biological processes including the transport of body water and is comprised of erythrocytes, white blood cells, platelets and plasma [ 5 ].
Several hydration tests involve the assessment of blood [ 18 ] collected using either venepuncture or a simple finger-prick lancet. Venepuncture samples are commonly used to assess blood composition, plasma solutes and hormone concentration [ 2 , 18 ].
Blood assessments are typically more invasive, expensive and time consuming than several alternative methods of assessing hydration, with an additional minor risk of infection or vein damage [ 18 ]. Furthermore, practical limitations can influence the collection and real-time analysis of blood in field-based settings, which should be considered when deciding which methods for assessing hydration are to be used.
Regardless, in most situations, blood variables are often more meaningful than their non-invasive counterparts [ 2 ]. Dehydration reduces total plasma volume, thus increasing the concentration of blood haematocrit [ 13 , 18 ]. Haematocrit is typically evaluated from a whole blood sample obtained via finger-prick lancet, capillary tubes and a centrifuge [ 18 , 22 ].
While haematocrit assessment does not require a phlebotomist, the specific equipment required for analysis does impose a cost barrier [ 2 , 18 ].
Measures of haematocrit provide an indication of plasma volume and can be used to estimate specific plasma volume loss using theoretical equations if haemoglobin measures are also available [ 23 , 24 ].
As water is lost from the blood during dehydration the concentration of solutes increases and becomes more hypertonic [ 26 ]. This concentration is commonly assessed using freezing point osmometry of serum or plasma [ 4 , 18 ].
Some laboratories utilize plasma osmolality P OSM as a gold standard measure of hydration [ 27 ], which is a topic of debate [ 2 , 14 , 28 ]. Nevertheless, P OSM is a robust assessment of hydration [ 5 ]. This phenomenon could result in erroneously concluding a greater magnitude of rehydration occurred than truly did, iii P OSM is influenced by food as body water shifts from the vasculature into the gut [ 33 ], iv P OSM is highly individual and should be compared to baseline measures as opposed to well-known norms [ 5 , 28 ], and, v whilst there is a strong physiological basis for inferring the relationship between P OSM and intracellular hydration [ 5 , 28 ] it is still not a direct measure of cellular hydration which should be considered when interpreting results.
Fluid shifts during dehydration influence the concentration of electrolytes within the bloodstream [ 34 ]. The assessment of electrolytes are used within clinical settings to inform point of care decisions but can also be used for more general or even athlete hydration testing [ 5 , 35 ].
Sodium in particular can give information on hydration, however there is minimal data exploring the assessment of other electrolytes [ 5 , 18 ]. Serum sodium is similar to P OSM as it contributes to the majority of P OSM and hence the above limitations of P OSM also apply to serum sodium [ 5 , 36 ].
While there is evidence to suggest serum sodium is a robust measure there is evidence that the accuracy is less than P OSM [ 5 , 37 ]. Indeed, the sodium lost in sweat results in serum sodium being less responsive than P OSM [ 5 , 37 ]. Considering both methods require expensive equipment and trained personnel it seems more practical to use P OSM rather than serum sodium.
There appears to be a symbiotic relationship between fluid balance and several hormonal factors, such that, changes in hydration results in measurable changes in many hormone levels [ 22 , 38 ]. Arginine-vasopressin, renin, aldosterone and atriopeptin have been proposed to provide information on hydration status [ 3 , 38 , 39 ].
However, such hormone variables are not typically used in the assessment of hydration. This is likely due to the time and cost associated with analysis and that they are altered by exercise, water immersion and heat acclimation [ 4 , 40 , 41 , 42 ].
In some cases hormonal variables have been found to be sensitive to changes in hydration levels [ 43 ], while other research has found them to be unreliable [ 5 , 44 , 45 , 46 ]. Recently, a surrogate marker for arginine-vasopressin, copeptin has been used in hydration research with promising results, though further research is required to determine the reliability and validity of the marker across multiple settings [ 47 , 48 ].
More generally, further research is required to determine the accuracy and validity of hormonal responses to hydration status prior to their inclusion as a commonplace assessment of hydration status.
Blood is widely considered as a reliable fluid to assess hydration [ 2 , 5 ]. Many variables typically associated with blood may be assessable in other bodily fluids.
For example, electrolyte or hormone concentrations could theoretically be assessed in other fluids such as urine or tears, but further research is required to investigate the accuracy and sensitivity of such methods.
Blood collection is invasive which may serve as a barrier to utilisation in practical settings, hence other fluids such as urine, saliva or tears are worthy of consideration. However, when assessing athletes in laboratory conditions blood-based assessments of hydration should be utilised due to their validity and reliability as described.
In athletic settings it is also important to consider that blood variables will take time to process depending on the availability and proximity of the required equipment, which may lead to delays during important point of care decisions.
Urine is comprised of water and several other substances which increase in concentration as the volume of water decreases [ 49 ].
Urine output is influenced by fluid intake, diet e. electrolyte intake , drugs e. diabetes or kidney disease [ 49 ]. As a result, previous ingestion or medical conditions must be accounted for when assessing hydration via urine. Urinary hydration assessment methods include urine specific gravity USG , urine osmolality U OSM , urine colour U COL and urine volume [ 19 ].
A result greater than 1. It is possible to assess urine osmolality without an osmometer and instead using a hand-held conductivity meter [ 50 ], however this method is actually and extrapolation from USG.
Urine colour is a subjective evaluation of urochrome in the urine and uses a Likert scale. When more water is excreted, urine colour becomes paler and conversely becomes darker as less water is excreted [ 19 ]. Urine assessments are less invasive than blood variables, and with the exception of U OSM they are relatively inexpensive [ 2 , 19 ].
Based on this information, urinary measures should be used with caution and in conjunction with other methods. The convenience of urinary assessments makes them appealing in both laboratory and field-based settings.
However, single cut-off limits should be avoided where possible and instead comparisons to within-individual changes i. baseline measures implemented [ 59 ]. Of the urine variables, USG and U OSM appear the most reliable [ 5 , 54 ]. However, given the limitations of urine as a fluid in general, caution should be applied if researchers intend to utilise these as a substitute for blood assessments.
Additionally, urinary measures should be avoided in cases of rapid rehydration such as those occurring post weigh-ins during weight-restricted sports [ 7 , 15 , 54 ].
Due to the ease, speed of collection and analysis for urinary variables they are appealing for use in athletic settings but must be used carefully to avoid erroneous conclusions. For example, combining urinary measures with gross measures of body mass and a blood marker will vastly improve their practical usage.
Saliva osmolality and flow rate can be noninvasively sampled to estimate hydration status. Both salivary flow rate and osmolality respond to exercise-heat stress and fluid restriction but the variation between individuals is large [ 5 , 61 , 62 , 63 ]. In fact, the day-to-day variability of saliva osmolality has been reported to be almost 10 times greater than P OSM , body mass, or even USG [ 21 , 64 ].
Exercise also influences salivary sodium, potassium and protein which could confound measures of salivary osmolality [ 65 , 66 ]. Considering the poor reliability and large number of confounding factors associated with salivary variables, the use of this technique is questionable.
Other potential variables such as salivary electrolytes or hormones may provide a more reliable assessment of hydration, however, systematic examination is required to confirm or refute the validity, sensitivity and reliability in this setting.
A recent method of estimating hydration status involves assessing fluid of the eye. Tear osmolality has emerged as a strong candidate for hydration assessment [ 67 , 68 ].
Indeed, tear osmolality closely correlates with P OSM with the relationship being stronger than USG [ 20 ]. However, literature has reported a large variability of tear osmolality potentially due to evaporation and differences in collection techniques [ 20 , 67 ].
Recently, a non-invasive tear collection and analysing device has provided a potential solution for the disparate collection techniques [ 67 ]. However, a recent study using the non-invasive tear collection and analysing device found that while tear osmolality did change following exercise-induced fluid loss, it did not correlate to other laboratory hydration measures including plasma osmolality and urine specific gravity [ 69 ].
Further research using the non-invasive tear collection and analysing device reported an inability to reliably detect mild dehydration [ 70 ].
Tear osmolality may provide a non-invasive alternative to assess hydration, but further research is required to understand its reliability, precision, limitations and ideal collection techniques. If tear osmolality can be demonstrated to be appropriate and robust, the technique will be appealing in athletic settings due to possibly lower participant burden and high scientific accuracy.
Stable isotope dilution involves measuring trace amounts of a particular isotope usually deuterium oxide, 2 H 2 O in blood or urine and calculating the TBW [ 71 ].
The calculation of TBW is based on the dilution principle, with previous research reporting such methods as highly accurate [ 72 ]. After baseline measures are collected the subject ingests an oral solution containing a known amount of the chosen isotope.
Multiple samples are then collected over the following hours to determine TBW [ 73 , 74 ]. Such methods require costly equipment, significant periods of time and technical expertise [ 2 ]. While there is a strong body of research supporting the accuracy of stable isotope dilution [ 4 , 72 ] it is not a direct measure of cellular hydration but rather, is based on the assumption that the isotope will distribute equally throughout extracellular and intracellular fluids, which is unverified [ 2 ].
Additionally, it takes longer for isotopes to equilibrate within urine than blood so more time for data collection will be required for urine [ 72 ]. Stable isotope dilution may a highly accurate method of assessing hydration status, but due to technical limitations of the technique it is not realistic to use in many applied settings, though it may have uses in controlled laboratory settings.
Additionally, due to the time taken to complete analysis it is not a practical real time assessment of change in hydration status. However, due to its high accuracy it is an appropriate measure of hydration status under highly-controlled conditions.
While hydration can be assessed using several fluids throughout the body, there are also several assessments that take more gross estimates of hydration status such as body mass, vital signs and sensations of thirst, bioimpedance, dual-energy X-ray absorptiometry and neutron activation analysis [ 2 ].
These methods potentially alleviate the issue of using fluid from one compartment to predict the hydration status of the entire body. However, gross assessments of hydration status will likely be unable to determine fluid shifts within the body, which has practical implications.
Such assessment can provide a general indication of change in whole body fluid content. A range of equipment can assess body mass including underwater weighing, air displacement or floor scales [ 70 , 75 ].
Equipment accuracy varies, with floor scales having varying reliability and accuracy dependant on the model of scale and method of measurement used [ 76 , 77 ]. The process of estimating whole body sweat loss via body mass is far more complicated than one may expect.
The longer the period of time between measures, the greater the difficulty in maintaining appropriate controls to ensure body mass changes relate predominantly to changes in hydration. In an effort to account for the potential confounders, Cheuvront and Kenefick [ 77 ] have presented an equation for accurately determining change in body mass:.
When adequate controls i. Over long periods of time, changes to body composition reduce the accuracy of body mass hydration assessments [ 79 ]. Under the correct conditions and in conjunction with other assessments of hydration, body mass provides useful information on hydration status, especially within shorter periods of time i.
Hypohydration affects the cardiovascular system which can be used to assess hydration status. Plasma volume reduction influences total blood volume and theoretically blood pressure [ 81 ].
However, blood pressure is a poor diagnostic tool for hydration assessment due to how robustly it is regulated [ 5 , 15 , 70 , 82 ]. The reduction of blood volume resulting from hypohydration also reduces stroke volume and results in increased resting and submaximal heart rates [ 81 , 83 ].
As a result, change in heart rate from sitting to standing can be used to evaluate the degree of hypohydration [ 5 , 82 ]. Unfortunately, change in heart rate from sitting to standing has shown poor sensitivity and weak overall accuracy [ 84 ], though there is evidence to suggest it may be able to detect extracellular dehydration [ 70 ].
Heart rate is influenced by a wide range of factors outside of hydration status, thus making it problematic to assess changes in hydration status [ 5 , 84 ]. Physical signs such as sunken eyes, capillary refill time and skin turgor have also been shown to be highly inaccurate in diagnostic settings [ 4 , 5 ].
Thirst sensation may also be used to assess hydration status using various assessment scales [ 85 ]. Subjective sensation of thirst is typically assessed using a Likert scale ranging from 1 not at all thirsty to 9 very, very thirsty [ 86 ], while a rating of between 3 and 5 is typically used to identify mild hypohydration [ 85 ].
Recent research has reported that sensation of thirst can accurately detect mild dehydration [ 70 ]. However, perception of thirst is influenced by palatability, time allowed for fluid consumption, gastric distention, age, gender and heat acclimation status [ 87 , 88 , 89 ].
It is also possible that in athletic settings where athletes may wish to hide potential hypohydration e. during rapid weight loss in combat sports they could intentionally provide inaccurate results.
Thirst sensation lacks the precision for detailed evaluation of hydration status but could provide a useful approximation [ 2 , 70 ]. While vital signs and sensation of thirst may be important in understanding the physiological or perceptual responses associated with hydration, they themselves provide limited information on hydration status but may be of use in conjunction with other more robust assessments.
Dual-energy X-Ray absorptiometry DXA is commonly used as a measure of body composition with a focus on bone mineral density [ 90 ].
Though not the primary use of a DXA, it can be used to gather information on TBW. Indeed, body water is located primarily within the lean body mass component of the DXA output [ 90 , 91 ].
At rest and within short time-periods, changes in lean body mass measured by a DXA will be the result of changes in TBW [ 90 ]. However, exercise and food ingestion alter factors within the lean body mass measurement, namely the concentration of muscle glycogen [ 91 ] which may confound measures in athletic populations.
Additionally, the use of multiple measures to detect change would require the exposure of athletes to multiple bouts of radiation, albeit a small amount [ 92 ]. Bioelectrical impedance analysis can quickly and non-invasively assess TBW. It involves a low alternating current being directed through the body and the resistance of the current measured to estimate TBW [ 93 ].
Measurement precision can be affected by subject posture, skin temperature, electrolyte balance, ingestion of food, intense physical activity, alcohol ingestion and protein malnutrition [ 3 , 94 ].
Typical error for TBW assessment ranges from 1. However, predictions of extracellular and intracellular water are highly theoretical and further research is needed determine the accuracy of such calculations [ 2 , 22 ]. The accuracy of bioimpedance techniques is unclear with research indicating changes in body fluid volume and tonicity can influence accuracy [ 18 , 22 ].
As a result of the potential confounders and lack of scientific verification of using bioimpedance techniques to assess hydration status, previous research has discouraged its use when monitoring acute changes in hydration status [ 3 , 4 ].
However, bioimpedance techniques have potential but further research is required to determine the precision and reliability of bioimpedance before advocacy for inclusion in a hydration testing battery. Neutron activation analysis uses radiation detectors to measure total body chloride, potassium and sodium following exposure to a neutron field and using the results to determine extracellular and intracellular volume [ 2 , 71 ].
The scan typically takes one hour to complete and has been reported to be a highly accurate measure of TBW [ 2 , 71 , 95 ]. Neutron activation analysis only estimates TBW based on electrolytes throughout the body, as opposed to directly measuring it [ 2 ].
Neutron activation analysis requires costly equipment [ 71 ], significant periods of time and technical expertise to complete, with the additional issue of radiation exposure as part of the assessment [ 2 , 71 ].
However, like stable isotope dilution, neutron activation analysis is highly accurate and could be important in assessing the validity and accuracy of other methods.
The purpose of this review was to review the methods of assessing human hydration and provide recommendations in athletic settings. The assessment of human hydration is a complicated topic and there is no single flawless method of assessing hydration status Table 1.
The accuracy and validity of differing measures of hydration will vary depending on the situation. The first thing to consider is the objective of the assessment protocol. Assessments of hydration status can investigate specific locations or the body as a whole.
There may be scenarios where the assessment of a singular location is the objective, but in most cases, investigators will be aiming to get an indication of whole body hydration status, which the following section will focus on.
Investigators also need to consider whether repeated measures will be utilised Fig. When repeated measures will not be utilised, it is important to apply appropriate gross assessments i. neutron activation analysis, stable isotope dilution, bioimpedance and sensation of thirst and those derived from bodily fluids i.
Though the use of P OSM is clearly the most appropriate when only a single measure is being utilised [ 28 ]. When repeated measures are utilised, well-controlled assessments of body mass should be employed wherever possible. When subjects are engaging in exercise the potential influence of substrate utilisation and metabolic water production on body mass must be considered.
In cases where the investigators have access to laboratory equipment, they should try to implement as many assessments as possible from the following list: plasma osmolality, haematocrit, tear osmolality, USG, DXA, U OSM Fig. Without access to laboratory equipment, investigators should try to use bioimpedance, urine colour and sensation of thirst while considering that the validity of the battery will be lower than a laboratory-based protocol Fig.
Where possible, assessments of different bodily fluids will be valuable. While these guidelines are based on the current body of literature, it is important to update best practices as research progresses.
Following standardised protocols alongside carefully selecting tests in context of the specific scenario is essential. Regardless of the method utilised results should be compared to changes within an individual to control for biological variation between humans due to known differences in fluid retention volumes and sites [ 5 , 64 ].
The most accurate measures of assessing hydration status i. stable isotope dilution and neutron activation analysis require equipment that the majority of investigators will not have access to, and even when they do, due to the time required to complete the analysis it is not realistic to use them to assess change in hydration.
However, if the time and resources are available, they are likely to provide highly accurate measures. Blood variables especially P OSM are typically more accurate than other assessments of body fluids and while they do require specialised equipment and skills, most laboratories will have access to the appropriate resources.
Blood variables such as P OSM , serum sodium and haematocrit can be conducted relatively quickly, allowing them to conveniently assess changes in hydration which may inform point of care decisions.
Without access to advanced laboratory equipment, urine specific gravity is next best available option but must be used with careful consideration of its limitations. Other variables such as bioimpedance and tear osmolality should be used with caution until further comprehensive research is conducted to better understand their reliability and validity as assessments of hydration status Table 1.
However, in athletic settings the primary limitations will be logistical in nature such as limited access to equipment, expertise or time Table 2. In cases when logistical issues arise, it is important to try to work within such limitations to select the best testing battery possible and then interpret the results through a critical lens Fig.
We strongly recommend the use of multiple measures of hydration status simultaneously for three reasons: i no single measure of hydration is without limitations, nor is a comprehensive measure of intra- and extra-cellular hydration, so multiple assessment methods increases accuracy and validity, ii multiple assessments reduce the likelihood of incorrect categorisation of hydration i.
hypo, hyper or euhydrated due to measurement error, and, iii different methods of hydration assessment evaluate fluid in different parts of the body which all interact with each other intracellular, extracellular and both in the same variable so it is important to use multiple methods both gross and body fluids to give the investigator a more comprehensive picture of where fluid is retained within the body.
However, even in cases where multiple assessments are used with careful consideration of their limitations it is important to acknowledge there is currently no direct assessment of intra- and extra-cellular hydration and the current assessments are estimates only of the location of fluid within the body.
Finally, physiological changes associated with variations in hydration are not completely understood and the effects of hydration on both performance and health are more complicated than simply the location and total volume of body water.
Future research should aim to better understand the movement of fluid between different compartments in the body and how to best assess the hydration of such compartments. Development of an assessment of hydration that can directly assesses intra- and extra-cellular hydration would provide valuable results when trying to understand how hypohydration influences bodily function instead of simply looking at total body water.
Previous research has explored the concept of assessing hydration via a biopsy of muscle tissue which could provide a more direct measure of skeletal muscle hydration, however more research is needed to better understand the accuracy and reliability of any such method [ 96 , 97 , 98 ].
A muscle biopsy would be highly invasive and uncomfortable for subjects so its best usage may be as a reference assessment to test the accuracy of less invasive measures. Development of more accurate but less invasive measures of hydration status is important for cases where blood assessments are impractical.
More research investigating the accuracy, reliability, and validity of tear osmolality and bioimpedance is warranted. Ultrasound technology may also have the potential to provide information about hydration status but the technique is in its infancy and more research is required [ 5 , 99 ].
Finally, many assessments have not had their accuracy and reliability assessed in the case of rapid dehydration or rehydration which may significantly influence potential results, especially in cases where liquids lacking electrolytes are ingested for recovery [ 15 ].
While previous research has examined the assessment of hydration status in athletes, this review provides a novel set of guidelines for developing an assessment battery of hydration status for different situations.
There are a wide range of methods to assess hydration status. Some methods are supported by a large body of scientific research while others have little supporting evidence. Researchers should aim to systematically fill the gaps in research while pursuing new avenues of hydration assessment.
Practitioners and researchers who are aiming to assess hydration status need careful consideration when selecting a hydration status testing protocol to get valid and meaningful data.
Additionally, no assessment of hydration status is without limitations so investigators should be cautious in the collection and interpretation of data. Better understanding hydration assessment will have important applications in both clinical and athletic settings.
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The symptoms of exertional heat stress are tachycardia, hypotension, hyperventilation, vomiting, diarrhea, seizures and coma 4. Despite these serious effects, many athletes do not seriously consider the effects of hydration on athletic performance. Dehydration may cause a reduction in blood volume, decreased skin blood flow, decreased sweat rate, decreased heat dissipation, increased core temperature and an increased rate of glycogen use.
As dehydration reduces plasma volume and therefore increases blood viscosity, central venous pressure decreases and reduces the amount of blood returning to the heart. During peak athletic intensity, these changes can decrease the amount of blood entering the heart during diastole; the phase in the cardiac cycle where the heart relaxes and fills with blood.
Less blood entering the heart during diastole decreases the amount of blood that may possibly leave the heart during systole, the phase where the heart contracts, consequently decreasing cardiac output 2. An increased core temperature during a dehydrated state is accompanied by a larger aromatic amine response, possibly leading to an increased rate of glycogen breakdown in muscles.
An increased rate of glycogen breakdown may contribute to an increased level of fatigue in the muscles used during the athletic activity 2. The breakdown of glycogen during exercise leads to an intracellular increase of acids, principally lactic acid.
As lactic acid is produced by the breakdown of glycogen, pH decreases causing skeletal muscle fatigue 5. The athletes in a dehydrated state had an increased level of cortisol, which competes for certain enzymatic receptors in the body reducing the level of testosterone, the primary hormone required for muscle growth.
Additionally, increased cortisol concentration reduces the amount of testosterone released as a response to resistance-specific weight training 3. Studies on water intake are limited in data compared to intake of other nutrients.
There is no ideal amount of water that should be consumed. Despite the lacking data, the Institute of Medicine has declared an estimated ideal volume of water that people should consumed daily. Male adults above the age of 18 should consume about 4 litres. Females above the age of 18 should drink about 3 litres of water.
Water is involved in the majority of chemical reactions involved in athletic performance. It is important that athletes are hydrated before, during and after physical activity to achieve their maximal physical performance.
June Jeukendrup, Asker E. Sport Nutrition : An Introduction to Energy Production and Performance. Champaign, IL: Human Kinetics, Brown, Jordana.
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Many Dexalytics users know that adequate hydration will Low-carb and metabolic health athletic perfomrance and have perforkance whether it preformance possible to calculate hydration status Consistent meal frequency on body weight or body composition. S;orts, Oral diabetes treatment is a wide variation for hydration needs for athletes Oral diabetes treatment on the intensity of exercise and Oral diabetes treatment of activity that the athlete is involved in, environmental temperature and humidity that the athlete is working out in, and the sweat rate of the athlete. All of these variables make the calculation of hydration needs highly variable and individual. Water and Athletic Performance We all know that water is essential for overall health. For a pound athlete, this means a 4 pound sweat loss can result in decreased mental sharpness, decreased recovery, decreased metabolic rate and increased risk of injury. Assessing Hydration Status It is important to evaluate hydration status before, during, and after exercise.Chloe Updegraff, Michigan State University Extension Hair health benefits Kelsey Merrics, Oral diabetes treatment kinesiology perforance - June 05, Performancs activity Microbe-repellent materials result in a large amount of water and electrolyte loss, which can in turn lead Hydragion dehydration Hydration and sports performance metrics, and therefore affect athletic performance.
If an athlete is not properly hydrated, heat ssports can occur. Heat Antioxidant-rich heart health can Anti-cancer community minor side effects, such as muscle cramps and headaches, but can also Oral diabetes treatment more serious outcomes, such as loss of consciousness and Hhdration.
To prevent dehydration and especially dehydration that Hudration to heat illnessthere are a Hydration and sports performance metrics simple tools metrjcs athletes should use to maintain hydration throughout activity. Determining hydration performznce can be spodts using a self-assessment, according to the National Performanxe Athletic Association.
One of the easiest and Beetroot juice for natural detoxification reliable ways to Hyddation if an athlete is hydrated is pergormance Hydration and sports performance metrics color. A pale-yellow to clear Hydrqtion is the best indicator for hydration.
Another way for athletes spotts self-assess hydration Muscle pain in glycogen storage disease to weigh themselves before Hdration after activity and note how many pounds perfogmance lost through sweat. This performancee a moderate which can quickly jetrics to Hydration and sports performance metrics level of dehydration, where medical Hydration and sports performance metrics might be required.
Assuring performanc hydration can be Hydration and sports performance metrics a few ways. According to the American College of Sports Medicine Hydration and sports performance metrics, water should be Hydration and sports performance metrics throughout each Hydrationn every day before one feels Hydgation.
The feeling of thirst is actually one of the first signs of Emotional eating control. Drinking 16 ounces hours before activity and then another 8 ounces minutes before activity is recommended.
About ounces of water or an electrolyte drink is recommended every minutes during an activity that lasts less than 60 minutes. If exercising for longer than 60 minutes, an electrolyte drink of ounces every minutes should be used to replace lost fluids.
After activity is completed, it is recommended to use the weight loss calculation and consume ounces of a sports drink or water per pound of body weight lost, according to the American College of Sports Medicine.
Aside from drinking water throughout the day and during activity, athletes can also consume beverages or snacks with sodium and potassium to help maintain electrolyte balance.
As previously mentioned, electrolyte drinks are a good alternative to water when exercising more than 60 minutes, and they may be appropriate during other times depending on the intensity, surrounding temperature and duration of the activity. Sports drinks contain carbohydrates which help with energy balance, as well as and sodium and potassium to help maintain hydration.
However, it is important to note that sports drinks do have a lot of extra sugar and calories. They are not necessary unless the physical activity is intense or sustained for a long period of time. Additionally, as suggested by National Colligate Athletic Associationathletes can use fruits and vegetables to maintain hydration, as these foods are made of mostly water and can keep an athlete hydrated when included in everyday nutrition.
Hydration is an important aspect of athletic performance and can prevent the various negative outcomes of becoming dehydrated.
If peak performance is the goal, hydration must be prioritized. Drink enough water to sustain you through your workout, practice or game! Michigan State University Extension supports maintaining a balanced diet and keeping hydration levels up, especially during sports or other physical activity.
This article was published by Michigan State University Extension. Hydration for Performance. How much athletes should be drinking Assuring athlete hydration can be achieved a few ways. Other ways to stay hydrated Aside from drinking water throughout the day and during activity, athletes can also consume beverages or snacks with sodium and potassium to help maintain electrolyte balance.
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: Hydration and sports performance metrics| Importance of Hydration in Sport: Hydration Strategies For Athletes | Hyfration Google Scholar Ungaro Performanec, Reimel AJ, Oatmeal recipes RP, Oral diabetes treatment KA, Pahnke MD, Baker LB. Stay Connected. Int J Clin Nutr. Photo by Getty Images. Mental Drills. For example, a body mass loss of 1 kg equating to approximately 1 L fluid would require the intake of 1. Elite Soccer. |
| Optimizing Hydration For Athletic Performance | Effects of Dehydration on Athletic Performance. Home Exercise Running Effects of Dehydration on Athletic Performance. Previous Next. Signs of Dehydration Dehydration occurs when there is a decrease in total body water content due to fluid loss, diminished fluid intake, or both. Importance of Hydration for Athletic Performance Did you know that not staying properly hydrated can reduce exercise endurance nearly in half? How to Hydrate Luckily, there are ways to ensure proper hydration before your activity, during your activity, and after your activity. Before Activity The goal is to be hydrated well before you even begin your physical activity. Anticipate your thirst and take a sip of water to stay ahead. Plan your activities a day in advance and properly hydrate the evening prior to put yourself in the best possible position to succeed. During Activity To keep up with your hydration throughout your activity, make sure to be drinking enough fluid to combat the water lost through sweat while also avoiding excessive body fluid loss and over-consumption of fluids. Activities lasting longer than 90 minutes require electrolyte replenishment. Having a sports drink along with your water is helpful and will provide additional benefits in staying hydrated. Post Activity The goal of hydration post activity is to replace any fluid deficit you lost during your activity. Replacing these fluids after your workout or game will restore hydration, improve recovery, reduce hypo-hydration symptoms, and decrease post-exercise fatigue. If you lost plus or minus 1. If the number is greater than 1. Schedule an appointment today References Jeukendrup, Asker, and Michael Gleeson. Shaheen, Naila A, et al. It is possible to drink too much water too fast and develop a condition called hyponatremia. It should be noted that this happens very rarely in athletes and dehydration is more common. Finally, hydration is highly variable from athlete to athlete necessitating the need for individualized hydration plans. References: Armstrong LE. Assessing hydration status. The elusive gold standard. J Am Coll Nutr. Armstrong LE, Herrera Soto JA, Hacker FT, Casa DJ, Kavouras SA, Maresh CM. Urinary indices during dehydration, exercise, and rehydration. Int J Sport Nutr Exerc Metab. Cheuvront SN, Montain SJ, Sawka MN. Fluid replacement and performance during the marathon. Sport Med. Dougherty KA, Baker LB, Chow M, Kenney, WL. Search the site Search. My Account. My Library. Search the site. Remember Login. Register Reset Password. x You are viewing 1 of your 1 free articles. It actually requires a good deal more thought. Andrew Hamilton explains. Andrew Hamilton explains Lies and damn lies? Although the importance of maintaining hydration in sport is relatively straightforward compared to other aspects of sports nutrition, and has been studied for longer than just about any other area, new research continues to turn up surprising findings. A good example of this is the controversy that currently surrounds the advice given to athletes wishing to maintain optimum hydration. Official advice to athletes to drink enough to replace fluid lost in sweat during endurance events is coming under increasing attack from scientists. In particular, they wanted to test two theories: 1. That the progressive dehydration commonly experienced by Ironman triathletes reflected in body weight reduction would be linked with rises in core body temperature; 2. What they discovered surprised them; while fluid losses led to an average fall in body mass of 2. Ironman triathletes can be assured that their brains will take care of their bodies during exercise, and that there is no need to follow industry favourable guidelines to drink to excess to ensure their safety. One could equally ask whether those 10 subjects competing in the Australian Ironman could have performed better if they had consumed more fluid and reduced their dehydration levels. Running economy refers to the biochemical and biomechanical efficiency of running; for any given running speed, the lower the oxygen requirement to maintain that speed, the greater the running economy. In the study, 10 highly trained collegiate distance runners mean age 20yrs, mean body mass The researchers measured a number of variables including hormone levels, body temperature, cardiovascular function and perceived rates of exertion. The results were surprising to say the least; there were no significant differences in running economy between any of the combinations of hydration states and workloads. Likewise, there were no differences in perceived rates of exertion or in post-exercise lactate concentration. Why is this surprising? Moreover, studies have shown that running economy is normally fairly sensitive to physiological disturbances, dropping significantly when fatigue sets in. In a double blind, randomised study on basketball players at Pennsylvania State University, US scientists set out to investigate the effects of three hydration strategies on 15 basketballers age 12 to 15 years who underwent three separate two-hour exercise sessions in hot conditions with different drinking strategies 5 : 1. Nine collegiate runners completed four minute treadmill runs differing in pre-exercise hydration states. Furthermore, the hydration state of the runners had no measurable effect on testosterone concentrations before, during, or after exercise at either intensity. In plain English, running or performing other types of exercise while in state of dehydration caused an unfavourable shift in the resulting hormone balance, by producing a more catabolic environment compared to full hydration. There are also implications here for immunity, as exercise-induced stress hormone release is known to be associated with decreased post-exercise immunity 9. Andrew Hamilton Andrew Hamilton BSc Hons, MRSC, ACSM, is the editor of Sports Performance Bulletin and a member of the American College of Sports Medicine. Register now to get a free Issue. Register now and get a free issue of Sports Performance Bulletin Get My Free Issue. Latest Issue. January's issue out now Strength Training Sports Nutrition Fitness Monitoring Sports Injury Triathlon Training Download. Subscribe Today. 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| Hydration for Athletes | Learn more about the signs and symptoms of dehydration. Dehydration contributes to muscle fatigue, which can increase the risk for injury. Staying adequately hydrated can help reduce muscle fatigue and reduce the risk of injury. As athletes exercise, the core body temperature rises. In response, the body sweats to dissipate excess heat so it doesn't overheat. Staying hydrated replaces the water lost through sweating and is essential for thermoregulation, helping to prevent cramps, heat exhaustion and heat stroke. Fluid needs vary based on activity, intensity, environmental conditions, body size of the athlete and training status. The more highly trained an athlete is, the more he or she will sweat and require more water. To maintain optimal hydration throughout the day, young athletes should drink ½ to 1 ounce of water per pound of body weight. This means that a pound athlete should lose no more than 2 pounds during a workout. Athletes should drink plenty of water in the hours leading up to practice. Continue taking four to six big gulps of water every 15 to 20 minutes during exercise. After exercising, drink 24 ounces of water for every pound of water weight you lose during your workout. Knowing an athlete's sweat rate is important when monitoring hydration. Sweat rate is the amount or rate at which a person sweats. To calculate sweat rate, measure weight before and after a workout. My Account. My Library. Search the site. Remember Login. Register Reset Password. x You are viewing 1 of your 1 free articles. It actually requires a good deal more thought. Andrew Hamilton explains. Andrew Hamilton explains Lies and damn lies? Although the importance of maintaining hydration in sport is relatively straightforward compared to other aspects of sports nutrition, and has been studied for longer than just about any other area, new research continues to turn up surprising findings. A good example of this is the controversy that currently surrounds the advice given to athletes wishing to maintain optimum hydration. Official advice to athletes to drink enough to replace fluid lost in sweat during endurance events is coming under increasing attack from scientists. In particular, they wanted to test two theories: 1. That the progressive dehydration commonly experienced by Ironman triathletes reflected in body weight reduction would be linked with rises in core body temperature; 2. What they discovered surprised them; while fluid losses led to an average fall in body mass of 2. Ironman triathletes can be assured that their brains will take care of their bodies during exercise, and that there is no need to follow industry favourable guidelines to drink to excess to ensure their safety. One could equally ask whether those 10 subjects competing in the Australian Ironman could have performed better if they had consumed more fluid and reduced their dehydration levels. Running economy refers to the biochemical and biomechanical efficiency of running; for any given running speed, the lower the oxygen requirement to maintain that speed, the greater the running economy. In the study, 10 highly trained collegiate distance runners mean age 20yrs, mean body mass The researchers measured a number of variables including hormone levels, body temperature, cardiovascular function and perceived rates of exertion. The results were surprising to say the least; there were no significant differences in running economy between any of the combinations of hydration states and workloads. Likewise, there were no differences in perceived rates of exertion or in post-exercise lactate concentration. Why is this surprising? Moreover, studies have shown that running economy is normally fairly sensitive to physiological disturbances, dropping significantly when fatigue sets in. In a double blind, randomised study on basketball players at Pennsylvania State University, US scientists set out to investigate the effects of three hydration strategies on 15 basketballers age 12 to 15 years who underwent three separate two-hour exercise sessions in hot conditions with different drinking strategies 5 : 1. Nine collegiate runners completed four minute treadmill runs differing in pre-exercise hydration states. Furthermore, the hydration state of the runners had no measurable effect on testosterone concentrations before, during, or after exercise at either intensity. In plain English, running or performing other types of exercise while in state of dehydration caused an unfavourable shift in the resulting hormone balance, by producing a more catabolic environment compared to full hydration. There are also implications here for immunity, as exercise-induced stress hormone release is known to be associated with decreased post-exercise immunity 9. Andrew Hamilton Andrew Hamilton BSc Hons, MRSC, ACSM, is the editor of Sports Performance Bulletin and a member of the American College of Sports Medicine. Register now to get a free Issue. Register now and get a free issue of Sports Performance Bulletin Get My Free Issue. Latest Issue. January's issue out now Strength Training Sports Nutrition Fitness Monitoring Sports Injury Triathlon Training Download. Subscribe Today. Unlimited Access Monthly Magazine Back Issue Library Email Newsletter. More on this Sports nutrition: is Coca-Cola an effective sports drink? Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Sawka MN, Cheuvront SN, Kenefick RW. Hypohydration and human performance: impact of environment and physiological mechanisms. Sports Med. Bushman, B. Exercise in the Heat and Adequate Hydration. ACSM Health Fitness J. DOI: Lopez, R. Exercise and Hydration: Individualizing Fluid Replacement Guidelines. Strength Conditioning J. Shirreffs, S. Hydration in Sport and Exercise: Water, Sports Drinks and Other Drinks. Nutrition Bulletin. By Laura Williams Laura Williams is a fitness expert and advocate with certifications from the American Council on Exercise and the American College of Sports Medicine. Use limited data to select advertising. Create profiles for personalised advertising. Use profiles to select personalised advertising. Create profiles to personalise content. Use profiles to select personalised content. Measure advertising performance. Measure content performance. Understand audiences through statistics or combinations of data from different sources. Develop and improve services. Use limited data to select content. List of Partners vendors. Sports Nutrition. Hydration Guide Hydration Guide. Hydration Hydration for Athletes Dehydration Health Benefits of Hydration Water vs. Sports Drink How to Boost Flavor. By Laura Williams. Laura Williams. Laura Williams is a fitness expert and advocate with certifications from the American Council on Exercise and the American College of Sports Medicine. Learn about our editorial process. Learn more. Medical Reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Medically reviewed by Jonathan Valdez, RDN, CDCES, CPT. Learn about our Medical Review Board. Table of Contents View All. Table of Contents. Hydration Guidelines for Athletes. Calculating Recommended Water Intake. When to Hydrate. When Should You Drink Water vs. Frequently Asked Questions. Next in Hydration Guide. Ramin Modabber, MD There is no formula for what an ideal amount of fluid consumption is. Ramin Modabber, MD. How to Know if You Need a Hydration Supplement. Choose Hydrating Foods Remember that in addition to drinking water and other fluids, fruits and vegetables are considered hydrating foods. Rathna Nuti, MD Thirst is not a dehydration barometer. How to Properly Rehydrate After a Workout. Drinks for Restoring Electrolyte Balance To help you decide which drinks to use, Dr. Frequently Asked Questions How much water should an athlete drink each day in cups? Learn More: Water or Sports Drinks — Which Is the Best Choice For You? How much water is too much for an athlete? Learn More: Keeping Hydrated During Your Runs. What are some easy ways for athletes to boost hydration? Learn More: Evidence-Based Health Benefits of Drinking Enough Water. |
| Post navigation | Equipment accuracy varies, with floor scales having varying reliability and accuracy dependant on the model of scale and method of measurement used [ 76 , 77 ]. The process of estimating whole body sweat loss via body mass is far more complicated than one may expect. The longer the period of time between measures, the greater the difficulty in maintaining appropriate controls to ensure body mass changes relate predominantly to changes in hydration. In an effort to account for the potential confounders, Cheuvront and Kenefick [ 77 ] have presented an equation for accurately determining change in body mass:. When adequate controls i. Over long periods of time, changes to body composition reduce the accuracy of body mass hydration assessments [ 79 ]. Under the correct conditions and in conjunction with other assessments of hydration, body mass provides useful information on hydration status, especially within shorter periods of time i. Hypohydration affects the cardiovascular system which can be used to assess hydration status. Plasma volume reduction influences total blood volume and theoretically blood pressure [ 81 ]. However, blood pressure is a poor diagnostic tool for hydration assessment due to how robustly it is regulated [ 5 , 15 , 70 , 82 ]. The reduction of blood volume resulting from hypohydration also reduces stroke volume and results in increased resting and submaximal heart rates [ 81 , 83 ]. As a result, change in heart rate from sitting to standing can be used to evaluate the degree of hypohydration [ 5 , 82 ]. Unfortunately, change in heart rate from sitting to standing has shown poor sensitivity and weak overall accuracy [ 84 ], though there is evidence to suggest it may be able to detect extracellular dehydration [ 70 ]. Heart rate is influenced by a wide range of factors outside of hydration status, thus making it problematic to assess changes in hydration status [ 5 , 84 ]. Physical signs such as sunken eyes, capillary refill time and skin turgor have also been shown to be highly inaccurate in diagnostic settings [ 4 , 5 ]. Thirst sensation may also be used to assess hydration status using various assessment scales [ 85 ]. Subjective sensation of thirst is typically assessed using a Likert scale ranging from 1 not at all thirsty to 9 very, very thirsty [ 86 ], while a rating of between 3 and 5 is typically used to identify mild hypohydration [ 85 ]. Recent research has reported that sensation of thirst can accurately detect mild dehydration [ 70 ]. However, perception of thirst is influenced by palatability, time allowed for fluid consumption, gastric distention, age, gender and heat acclimation status [ 87 , 88 , 89 ]. It is also possible that in athletic settings where athletes may wish to hide potential hypohydration e. during rapid weight loss in combat sports they could intentionally provide inaccurate results. Thirst sensation lacks the precision for detailed evaluation of hydration status but could provide a useful approximation [ 2 , 70 ]. While vital signs and sensation of thirst may be important in understanding the physiological or perceptual responses associated with hydration, they themselves provide limited information on hydration status but may be of use in conjunction with other more robust assessments. Dual-energy X-Ray absorptiometry DXA is commonly used as a measure of body composition with a focus on bone mineral density [ 90 ]. Though not the primary use of a DXA, it can be used to gather information on TBW. Indeed, body water is located primarily within the lean body mass component of the DXA output [ 90 , 91 ]. At rest and within short time-periods, changes in lean body mass measured by a DXA will be the result of changes in TBW [ 90 ]. However, exercise and food ingestion alter factors within the lean body mass measurement, namely the concentration of muscle glycogen [ 91 ] which may confound measures in athletic populations. Additionally, the use of multiple measures to detect change would require the exposure of athletes to multiple bouts of radiation, albeit a small amount [ 92 ]. Bioelectrical impedance analysis can quickly and non-invasively assess TBW. It involves a low alternating current being directed through the body and the resistance of the current measured to estimate TBW [ 93 ]. Measurement precision can be affected by subject posture, skin temperature, electrolyte balance, ingestion of food, intense physical activity, alcohol ingestion and protein malnutrition [ 3 , 94 ]. Typical error for TBW assessment ranges from 1. However, predictions of extracellular and intracellular water are highly theoretical and further research is needed determine the accuracy of such calculations [ 2 , 22 ]. The accuracy of bioimpedance techniques is unclear with research indicating changes in body fluid volume and tonicity can influence accuracy [ 18 , 22 ]. As a result of the potential confounders and lack of scientific verification of using bioimpedance techniques to assess hydration status, previous research has discouraged its use when monitoring acute changes in hydration status [ 3 , 4 ]. However, bioimpedance techniques have potential but further research is required to determine the precision and reliability of bioimpedance before advocacy for inclusion in a hydration testing battery. Neutron activation analysis uses radiation detectors to measure total body chloride, potassium and sodium following exposure to a neutron field and using the results to determine extracellular and intracellular volume [ 2 , 71 ]. The scan typically takes one hour to complete and has been reported to be a highly accurate measure of TBW [ 2 , 71 , 95 ]. Neutron activation analysis only estimates TBW based on electrolytes throughout the body, as opposed to directly measuring it [ 2 ]. Neutron activation analysis requires costly equipment [ 71 ], significant periods of time and technical expertise to complete, with the additional issue of radiation exposure as part of the assessment [ 2 , 71 ]. However, like stable isotope dilution, neutron activation analysis is highly accurate and could be important in assessing the validity and accuracy of other methods. The purpose of this review was to review the methods of assessing human hydration and provide recommendations in athletic settings. The assessment of human hydration is a complicated topic and there is no single flawless method of assessing hydration status Table 1. The accuracy and validity of differing measures of hydration will vary depending on the situation. The first thing to consider is the objective of the assessment protocol. Assessments of hydration status can investigate specific locations or the body as a whole. There may be scenarios where the assessment of a singular location is the objective, but in most cases, investigators will be aiming to get an indication of whole body hydration status, which the following section will focus on. Investigators also need to consider whether repeated measures will be utilised Fig. When repeated measures will not be utilised, it is important to apply appropriate gross assessments i. neutron activation analysis, stable isotope dilution, bioimpedance and sensation of thirst and those derived from bodily fluids i. Though the use of P OSM is clearly the most appropriate when only a single measure is being utilised [ 28 ]. When repeated measures are utilised, well-controlled assessments of body mass should be employed wherever possible. When subjects are engaging in exercise the potential influence of substrate utilisation and metabolic water production on body mass must be considered. In cases where the investigators have access to laboratory equipment, they should try to implement as many assessments as possible from the following list: plasma osmolality, haematocrit, tear osmolality, USG, DXA, U OSM Fig. Without access to laboratory equipment, investigators should try to use bioimpedance, urine colour and sensation of thirst while considering that the validity of the battery will be lower than a laboratory-based protocol Fig. Where possible, assessments of different bodily fluids will be valuable. While these guidelines are based on the current body of literature, it is important to update best practices as research progresses. Following standardised protocols alongside carefully selecting tests in context of the specific scenario is essential. Regardless of the method utilised results should be compared to changes within an individual to control for biological variation between humans due to known differences in fluid retention volumes and sites [ 5 , 64 ]. The most accurate measures of assessing hydration status i. stable isotope dilution and neutron activation analysis require equipment that the majority of investigators will not have access to, and even when they do, due to the time required to complete the analysis it is not realistic to use them to assess change in hydration. However, if the time and resources are available, they are likely to provide highly accurate measures. Blood variables especially P OSM are typically more accurate than other assessments of body fluids and while they do require specialised equipment and skills, most laboratories will have access to the appropriate resources. Blood variables such as P OSM , serum sodium and haematocrit can be conducted relatively quickly, allowing them to conveniently assess changes in hydration which may inform point of care decisions. Without access to advanced laboratory equipment, urine specific gravity is next best available option but must be used with careful consideration of its limitations. Other variables such as bioimpedance and tear osmolality should be used with caution until further comprehensive research is conducted to better understand their reliability and validity as assessments of hydration status Table 1. However, in athletic settings the primary limitations will be logistical in nature such as limited access to equipment, expertise or time Table 2. In cases when logistical issues arise, it is important to try to work within such limitations to select the best testing battery possible and then interpret the results through a critical lens Fig. We strongly recommend the use of multiple measures of hydration status simultaneously for three reasons: i no single measure of hydration is without limitations, nor is a comprehensive measure of intra- and extra-cellular hydration, so multiple assessment methods increases accuracy and validity, ii multiple assessments reduce the likelihood of incorrect categorisation of hydration i. hypo, hyper or euhydrated due to measurement error, and, iii different methods of hydration assessment evaluate fluid in different parts of the body which all interact with each other intracellular, extracellular and both in the same variable so it is important to use multiple methods both gross and body fluids to give the investigator a more comprehensive picture of where fluid is retained within the body. However, even in cases where multiple assessments are used with careful consideration of their limitations it is important to acknowledge there is currently no direct assessment of intra- and extra-cellular hydration and the current assessments are estimates only of the location of fluid within the body. Finally, physiological changes associated with variations in hydration are not completely understood and the effects of hydration on both performance and health are more complicated than simply the location and total volume of body water. Future research should aim to better understand the movement of fluid between different compartments in the body and how to best assess the hydration of such compartments. Development of an assessment of hydration that can directly assesses intra- and extra-cellular hydration would provide valuable results when trying to understand how hypohydration influences bodily function instead of simply looking at total body water. Previous research has explored the concept of assessing hydration via a biopsy of muscle tissue which could provide a more direct measure of skeletal muscle hydration, however more research is needed to better understand the accuracy and reliability of any such method [ 96 , 97 , 98 ]. A muscle biopsy would be highly invasive and uncomfortable for subjects so its best usage may be as a reference assessment to test the accuracy of less invasive measures. Development of more accurate but less invasive measures of hydration status is important for cases where blood assessments are impractical. More research investigating the accuracy, reliability, and validity of tear osmolality and bioimpedance is warranted. Ultrasound technology may also have the potential to provide information about hydration status but the technique is in its infancy and more research is required [ 5 , 99 ]. Finally, many assessments have not had their accuracy and reliability assessed in the case of rapid dehydration or rehydration which may significantly influence potential results, especially in cases where liquids lacking electrolytes are ingested for recovery [ 15 ]. While previous research has examined the assessment of hydration status in athletes, this review provides a novel set of guidelines for developing an assessment battery of hydration status for different situations. There are a wide range of methods to assess hydration status. Some methods are supported by a large body of scientific research while others have little supporting evidence. Researchers should aim to systematically fill the gaps in research while pursuing new avenues of hydration assessment. Practitioners and researchers who are aiming to assess hydration status need careful consideration when selecting a hydration status testing protocol to get valid and meaningful data. Additionally, no assessment of hydration status is without limitations so investigators should be cautious in the collection and interpretation of data. Better understanding hydration assessment will have important applications in both clinical and athletic settings. Horswill CA, Janas LM. Hydration and health. Am J Lifestyle Med. Article Google Scholar. Armstrong LE. Assessing hydration status: the elusive gold standard. J Am Coll Nutr. Kavouras SA. Assessing hydration status. Curr Opin Clin Nutr Metab Care. Cheuvront SN, Sawka MN. Hydration assessment of athletes. Sports Sci Exchange. Google Scholar. Cheuvront SN, Kenefick RW. Dehydration: physiology, assessment, and performance effects. Compr Physiol. Savoie F-A, Kenefick RW, Ely BR, Cheuvront SN, Goulet ED. Effect of Hypohydration on muscle endurance, strength, anaerobic power and capacity and vertical jumping ability: a meta-analysis. Sports Med. Barley OR, Chapman DW, Abbiss CR. The current state of weight-cutting in combat sports. Wall BA, Watson G, Peiffer JJ, Abbiss CR, Siegel R, Laursen PB. Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat. Br J Sports Med. James LJ, Funnell MP, James RM, Mears SA. Does hypohydration really impair endurance performance? Methodological considerations for interpreting hydration research. Cheuvront SN, Kenefick RW, Montain SJ, Sawka MN. Mechanisms of aerobic performance impairment with heat stress and dehydration. J Appl Physiol. Barley OR, Chapman DW, Blazevich AJ, Abbiss CR. Acute dehydration impairs endurance without modulating neuromuscular function. Front Physiol. Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC, et al. Exercise and fluid replacement. Med Sci Sports Exerc. Zubac D, Marusic U, Karnincic H. Hydration status assessment techniques and their applicability among Olympic combat sports athletes: literature review. Strength Cond J. Armstrong LE, Maughan RJ, Senay LC, Shirreffs SM. Limitations to the use of plasma osmolality as a hydration biomarker. Am J Clin Nutr. Article CAS Google Scholar. Barley OR, Iredale F, Chapman DW, Hopper A, Abbiss CR. Repeat effort performance is reduced 24 hours after acute dehydration in mixed martial arts athletes. J Strength Cond Res. Greenhalgh T, Thorne S, Malterud K. Time to challenge the spurious hierarchy of systematic over narrative reviews? Eur J Clin Invest. Sawka MN, Coyle EF. Influence of body water and blood volume on thermoregulation and exercise performance in the heat. Exerc Sport Sci Rev. CAS Google Scholar. Oppliger RA, Bartok C. Hydration testing of athletes. Fernández-Elías VE, Martínez-Abellán A, López-Gullón JM, Morán-Navarro R, Pallarés JG, De la Cruz-Sánchez E, et al. Validity of hydration non-invasive indices during the weightcutting and official weigh-in for Olympic combat sports. PLoS One. Fortes MB, Diment BC, Di Felice U, Gunn AE, Kendall JL, Esmaeelpour M, et al. Tear fluid osmolarity as a potential marker of hydration status. Ely BR, Cheuvront SN, Kenefick RW, Sawka MN. Limitations of salivary osmolality as a marker of hydration status. Shirreffs S. Markers of hydration status. J Sports Med Phys Fitness. Sawka MN, Young AJ, Pandolf KB, Dennis RC, Valeri RC. Erythrocyte, plasma, and blood volume of healthy young men. Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. Robertson J, Maughan R, Davidson R. Changes in red cell density and related indices in response to distance running. Eur J Appl Physiol Occup Physiol. Popowski LA, Oppliger RA, Patrick LG, Johnson RF, Kim JA, Gisolf C. Blood and urinary measures of hydration status during progressive acute dehydration. Sollanek KJ, Kenefick RW, Cheuvront SN, Axtell RS. Potential impact of a mL water bolus and body mass on plasma osmolality dilution. Eur J Appl Physiol. Cheuvront SN, Kenefick RW, Charkoudian N, Sawka MN. Physiologic basis for understanding quantitative dehydration assessment. Hamouti N, Del Coso J, Mora-Rodriguez R. Comparison between blood and urinary fluid balance indices during dehydrating exercise and the subsequent hypohydration when fluid is not restored. Francesconi R, Hubbard R, Szlyk P, Schnakenberg D, Carlson D, Leva N, et al. Urinary and hematologic indexes of hypohydration. Armstrong LE, Maresh CM, Castellani JW, Bergeron MF, Kenefick RW, LaGasse KE, et al. Urinary indices of hydration status. Int J Sport Nutr. Nose H, Mack GW, Shi X, Nadel ER. Shift in body fluid compartments after dehydration in humans. Gill G, Baylis P, Flear C, Lawson J. Changes in plasma solutes after food. J R Soc Med. Montain SJ, Cheuvront SN, Carter R. Sawka MN. DTIC Document: Human water and electrolyte balance; Chacko B, Peter JV, Patole S, Fleming JJ, Selvakumar R. Electrolytes assessed by point-of-care testing—are the values comparable with results obtained from the central laboratory? Indian J Crit Care Med. Edelman I, Leibman J, O'meara M, Birkenfeld L. Interrelations between serum sodium concentration, serum osmolarity and total exchangeable sodium, total exchangeable potassium and total body water. J Clin Invest. Cheuvront SN, Kenefick RW, Sollanek KJ, Ely BR, Sawka MN. Water-deficit equation: systematic analysis and improvement. Stachenfeld NS, Gleim GW, Zabetakis PM, Nicholas JA. Fluid balance and renal response following dehydrating exercise in well-trained men and women. Schrier R, Berl T, Anderson R. Osmotic and nonosmotic control of vasopressin release. Am J Physiol Renal Physiol. Francesconi R, Sawka MN, Pandolf KB. Hypohydration and heat acclimation: plasma renin and aldosterone during exercise. Montain SJ, Laird JE, Latzka WA, Sawka MN. Aldosterone and vasopressin responses in the heat: hydration level and exercise intensity effects. Hammerum MS, Bie P, Pump B, Johansen LB, Christensen NJ, Norsk P. Vasopressin, angiotensin II and renal responses during water immersion in hydrated humans. J Physiol. Brandenberger G, Candas V, Follenius M, Kahn J. The influence of the initial state of hydration on endocrine responses to exercise in the heat. Zerbe R, Miller J, Robertson G. The reproducibility and heritability of individual differences in osmoregulatory function in normal human subjects. J Lab Clin Med. Ahokoski O, Virtanen A, Kairisto V, Scheinin H, Huupponen R, Irjala K. Biological day-to-day variation and reference change limits of serum cortisol and aldosterone in healthy young men on unrestricted diets. Clin Chem. Ricos C, Arbos M. Hydration for athletes is essential to maintain normal blood circulation because this aids the delivery of nutrients and oxygen to every working muscle in the body. To stay hydrated, it is good to practise carrying a bottle of water around, especially during training. To satisfy the demand for water for bodily functions, fluids typically drinking water should be consumed regularly throughout the day. In this instance, the body cannot perform at its best, and severe dehydration can cause serious health problems, even death. Many factors can influence hydration status and must be considered to apply suitable hydration strategies to prevent dehydration. As previously mentioned, your body utilises body water to function and metabolise energy food. Staying hydrated comes with various benefits for bodily functions. Critical reasons are that it helps regulate our body temperature, keeps joints in minimal friction, delivers nutrients to cells, proper organ functions, stable sleeping cycles, maintains brain function, better performance prevents constipation, and many more direct and indirect benefits. Staying adequately hydrated is the key to prevent injuries caused by muscle fatigue which in turn leads to increased chances for injury. Also, Learn about foods to speed up muscle recovery. The average person should drink L water a day at a minimum, plus approx ml-1L fluids for every hour of exercise. Drinking excessive amounts of water without additional electrolytes, i. sodium can cause electrolyte imbalances and reduced concentrations in blood, called hyponatremia. While there are no official guidelines for drinking water, it is recommended you drink from 2 to 3 litres of water drank little and often throughout the day, plus ml-1L per hour of exercise. It is recommended that you drink to ml of water two hours before any form of exercise. During exercise, you lose plenty of fluid through sweat to regulate body heat. To replace fluid through sweat, we need to drink sufficient water. During exercise, athletes will typically lose anywhere between 0. This can depend on training duration, but water is still the first point of call. Sweat contains electrolytes such as sodium and water, so simply drinking only water when sweat rates are high during prolonged training could be susceptible to hyponatremia, an imbalance between body water and sodium levels causing a diluted effect. Electrolytes aid absorption across the intestine, retain body water in cells and are also involved in muscle and nerve function. Carbohydrates may also be required during high-volume training, but without adequate hydration, they will not be adequately absorbed. It also contains a small number of carbohydrates that are sufficient to fuel your training and boost brain and muscle function without unwanted GI problems. During exercise or any physical activity, which can include daily chores like gardening or hoovering, our core body temperature will rise. When this occurs, our body will automatically respond by trying to maintain a level of homeostasis by cooling itself down thermoregulation. So, there is a great importance of water for athletes. By doing this, the body will start to sweat, allowing water to be evaporated from the skin and release heat. During prolonged periods of exercise, sweat rates can increase and lead to dehydration if fluids are not consumed to alleviate this deficit. This will ultimately impair exercise performance and, in severe conditions, can be hazardous to health. Calculating your sweat rate is a practical and important technique for getting the most from your nutrition to maximise performance. Weighing yourself before and after training and measuring how much you drink during that session is all you need to get a good estimate. Drinking 1. Otherwise, it will be passed out in the urine. But, when considering other nutritional requirements after training, your body may also need protein and carbohydrates. Milk is a natural source of protein, carbohydrates, and sodium and is more effective for hydration, protein synthesis, and glycogen replenishment than commercialised sports drinks. So if you have milk to hand, then this could be your best choice. Another factor to consider is the weather. Therefore, it would be prudent to include more fluids with added sodium during and after training. Dehydration increases your chances of underperforming through various cardio strains and thermal strains of heat illness. Water and Athletic Performance We all know that water is essential for overall health. For a pound athlete, this means a 4 pound sweat loss can result in decreased mental sharpness, decreased recovery, decreased metabolic rate and increased risk of injury. Assessing Hydration Status It is important to evaluate hydration status before, during, and after exercise. There are several ways to measure hydration status and a hydration plan should be determined for each athlete. The simplest method for measuring adequate hydration and fluid needs during exercise is to measure body weight difference. A change in body weight from pre-exercise to post-exercise typically indicates the amount of fluid lost during exercise correcting for weight of fluid, food intake, urine and fecal losses, and sweating Armstrong, Another hydration indice is the hour urine volume. To calculate hour urine volume one must collect all urine that is produced throughout a day in a clean plastic jug. A healthy woman produces about 1. Measuring specific gravity is another method to measure hydration status. This requires a refractometer to measure the density of urine relative to the density of water. In dehydrated states, the specific gravity of urine exceeds 1. Normal urine specific gravity ranges from 1. Urine color can be another method to determine hydration status. |
| How Much Water Should An Athlete Drink Each Day: Expert Recommended Hydration Guidelines | To learn more about how to perform at your best, talk to a specialist at Sanford Sports. Posted In Healthy Living , Nutrition , Sanford Sports , Sports Medicine. Written by Ellen Koester. April 11, Photo by Getty Images. Everyday hydration Proper hydration starts before you hit the court, field or gym. Ellen Koester Ellen Koester is a web copywriter for Sanford Health. Stay up to date with news from Sanford Health. Sign Up. Stay Connected. About Sanford Medical Professionals Mobile Apps Video Library Sanford Health News Classes and Events Careers Contact Media Relations Donate Volunteer Resources Patient Education Sanford Health Plan Sanford Health Foundation Sanford Imagenetics Sanford Research Sanford Innovations Edith Sanford Breast Center Sanford World Clinic Sanford Wellness Centers Lorraine Cross Award. Benefits of staying hydrated include: Improved muscle function. Hydrated muscles function better than dehydrated muscles. Regulated blood pressure. Improved circulation. Staying hydrated also improves blood flow and circulation and thus the delivery of oxygen and nutrients to working muscles. Good hydration also helps remove metabolic by-products and waste from muscles, while replacing the water that is lost through sweat. How can proper hydration help young athletes reduce injury risk? Recommended daily water intake for athletes Fluid needs vary based on activity, intensity, environmental conditions, body size of the athlete and training status. Calculating sweat rate Knowing an athlete's sweat rate is important when monitoring hydration. Water or sports drink: What is best for athletes? Sports drinks may be recommended in certain situations including when: Exercise lasts longer than 1 hour Engaging in intense workouts Practicing or playing in extreme environmental conditions, such as high heat and humidity Excessive sweating occurs, i. Learn more The specially trained experts at Children's Health Andrews Institute Sports Performance powered by EXOS help young athletes perform their best while remaining healthy and safe. Thank you! You are now subscribed to the Performance Playbook newsletter. Sign up for Performance Playbook Receive the latest advice from our orthopedic and sports performance specialist -- right in your inbox. Please enter a valid email address. Google Scholar. Cheuvront SN, Kenefick RW. Dehydration: physiology, assessment, and performance effects. Compr Physiol. Savoie F-A, Kenefick RW, Ely BR, Cheuvront SN, Goulet ED. Effect of Hypohydration on muscle endurance, strength, anaerobic power and capacity and vertical jumping ability: a meta-analysis. Sports Med. Barley OR, Chapman DW, Abbiss CR. The current state of weight-cutting in combat sports. Wall BA, Watson G, Peiffer JJ, Abbiss CR, Siegel R, Laursen PB. Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat. Br J Sports Med. James LJ, Funnell MP, James RM, Mears SA. Does hypohydration really impair endurance performance? Methodological considerations for interpreting hydration research. Cheuvront SN, Kenefick RW, Montain SJ, Sawka MN. Mechanisms of aerobic performance impairment with heat stress and dehydration. J Appl Physiol. Barley OR, Chapman DW, Blazevich AJ, Abbiss CR. Acute dehydration impairs endurance without modulating neuromuscular function. Front Physiol. Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC, et al. Exercise and fluid replacement. Med Sci Sports Exerc. Zubac D, Marusic U, Karnincic H. Hydration status assessment techniques and their applicability among Olympic combat sports athletes: literature review. Strength Cond J. Armstrong LE, Maughan RJ, Senay LC, Shirreffs SM. Limitations to the use of plasma osmolality as a hydration biomarker. Am J Clin Nutr. Article CAS Google Scholar. Barley OR, Iredale F, Chapman DW, Hopper A, Abbiss CR. Repeat effort performance is reduced 24 hours after acute dehydration in mixed martial arts athletes. J Strength Cond Res. Greenhalgh T, Thorne S, Malterud K. Time to challenge the spurious hierarchy of systematic over narrative reviews? Eur J Clin Invest. Sawka MN, Coyle EF. Influence of body water and blood volume on thermoregulation and exercise performance in the heat. Exerc Sport Sci Rev. CAS Google Scholar. Oppliger RA, Bartok C. Hydration testing of athletes. Fernández-Elías VE, Martínez-Abellán A, López-Gullón JM, Morán-Navarro R, Pallarés JG, De la Cruz-Sánchez E, et al. Validity of hydration non-invasive indices during the weightcutting and official weigh-in for Olympic combat sports. PLoS One. Fortes MB, Diment BC, Di Felice U, Gunn AE, Kendall JL, Esmaeelpour M, et al. Tear fluid osmolarity as a potential marker of hydration status. Ely BR, Cheuvront SN, Kenefick RW, Sawka MN. Limitations of salivary osmolality as a marker of hydration status. Shirreffs S. Markers of hydration status. J Sports Med Phys Fitness. Sawka MN, Young AJ, Pandolf KB, Dennis RC, Valeri RC. Erythrocyte, plasma, and blood volume of healthy young men. Dill DB, Costill DL. Calculation of percentage changes in volumes of blood, plasma, and red cells in dehydration. Robertson J, Maughan R, Davidson R. Changes in red cell density and related indices in response to distance running. Eur J Appl Physiol Occup Physiol. Popowski LA, Oppliger RA, Patrick LG, Johnson RF, Kim JA, Gisolf C. Blood and urinary measures of hydration status during progressive acute dehydration. Sollanek KJ, Kenefick RW, Cheuvront SN, Axtell RS. Potential impact of a mL water bolus and body mass on plasma osmolality dilution. Eur J Appl Physiol. Cheuvront SN, Kenefick RW, Charkoudian N, Sawka MN. Physiologic basis for understanding quantitative dehydration assessment. Hamouti N, Del Coso J, Mora-Rodriguez R. Comparison between blood and urinary fluid balance indices during dehydrating exercise and the subsequent hypohydration when fluid is not restored. Francesconi R, Hubbard R, Szlyk P, Schnakenberg D, Carlson D, Leva N, et al. Urinary and hematologic indexes of hypohydration. Armstrong LE, Maresh CM, Castellani JW, Bergeron MF, Kenefick RW, LaGasse KE, et al. Urinary indices of hydration status. Int J Sport Nutr. Nose H, Mack GW, Shi X, Nadel ER. Shift in body fluid compartments after dehydration in humans. Gill G, Baylis P, Flear C, Lawson J. Changes in plasma solutes after food. J R Soc Med. Montain SJ, Cheuvront SN, Carter R. Sawka MN. DTIC Document: Human water and electrolyte balance; Chacko B, Peter JV, Patole S, Fleming JJ, Selvakumar R. Electrolytes assessed by point-of-care testing—are the values comparable with results obtained from the central laboratory? Indian J Crit Care Med. Edelman I, Leibman J, O'meara M, Birkenfeld L. Interrelations between serum sodium concentration, serum osmolarity and total exchangeable sodium, total exchangeable potassium and total body water. J Clin Invest. Cheuvront SN, Kenefick RW, Sollanek KJ, Ely BR, Sawka MN. Water-deficit equation: systematic analysis and improvement. Stachenfeld NS, Gleim GW, Zabetakis PM, Nicholas JA. Fluid balance and renal response following dehydrating exercise in well-trained men and women. Schrier R, Berl T, Anderson R. Osmotic and nonosmotic control of vasopressin release. Am J Physiol Renal Physiol. Francesconi R, Sawka MN, Pandolf KB. Hypohydration and heat acclimation: plasma renin and aldosterone during exercise. Montain SJ, Laird JE, Latzka WA, Sawka MN. Aldosterone and vasopressin responses in the heat: hydration level and exercise intensity effects. Hammerum MS, Bie P, Pump B, Johansen LB, Christensen NJ, Norsk P. Vasopressin, angiotensin II and renal responses during water immersion in hydrated humans. J Physiol. Brandenberger G, Candas V, Follenius M, Kahn J. The influence of the initial state of hydration on endocrine responses to exercise in the heat. Zerbe R, Miller J, Robertson G. The reproducibility and heritability of individual differences in osmoregulatory function in normal human subjects. J Lab Clin Med. Ahokoski O, Virtanen A, Kairisto V, Scheinin H, Huupponen R, Irjala K. Biological day-to-day variation and reference change limits of serum cortisol and aldosterone in healthy young men on unrestricted diets. Clin Chem. Ricos C, Arbos M. Quality goals for hormone testing. Ann Clin Biochem. Jansen LT, Suh H, Adams J, Sprong CA, Seal AD, Scott DM, et al. Osmotic stimulation of vasopressin acutely impairs glucose regulation: a counterbalanced, crossover trial. Enhörning S, Brunkwall L, Tasevska I, Ericson U, Persson Tholin J, Persson M, et al. Water supplementation reduces copeptin and plasma glucose in adults with high copeptin: the H2O metabolism pilot study. J Clin Endocrinol Metab. Zubac D, Reale R, Karnincic H, Sivric A, Jelaska I. Urine specific gravity as an indicator of dehydration in Olympic combat sport athletes; considerations for research and practice. Eur J Sport Sci. Shirreffs SM, Maughan RJ. Urine osmolality and conductivity as indices of hydration status in athletes in the heat. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Armstrong LE, Herrera Soto JA, Hacker FT Jr, Casa DJ, Kavouras SA, Maresh CM. Urinary indices during dehydration, exercise, and rehydration. Oppliger RA, Magnes SA, Popowski LA, Gisolfi CV. Accuracy of urine specific gravity and osmolality as indicators of hydration status. Int J Sport Nutr Exerc Metab. Zubac D, Paravlic A, Reale R, Jelaska I, Morrison SA, Ivancev V. Fluid balance and hydration status in combat sport Olympic athletes: a systematic review with meta-analysis of controlled and uncontrolled studies. Eur J Nutr. Rowat A, Smith L, Graham C, Lyle D, Horsburgh D, Dennis M. A pilot study to assess if urine specific gravity and urine colour charts are useful indicators of dehydration in acute stroke patients. J Adv Nurs. Freedman SB, Vandermeer B, Milne A, Hartling L, Johnson D, Black K, et al. Diagnosing clinically significant dehydration in children with acute gastroenteritis using noninvasive methods: a meta-analysis. J Pediatr. Armstrong LE, Maresh CM, Gabaree CV, Hoffman JR, Kavouras SA, Kenefick RW, et al. Thermal and circulatory responses during exercise: effects of hypohydration, dehydration, and water intake. Zubac D, Cular D, Marusic U. Reliability of urinary dehydration markers among elite youth boxers. Int J Sports Physiol Perform. Cheuvront SN, Kenefick RW, Zambraski EJ. Spot urine concentrations should not be used for hydration assessment: a methodology review. Hew-Butler T, Weisz K. The hydration sweet spot: importance of Aquaporins. Clin Lab Sci. Oliver SJ, Laing SJ, Wilson S, Bilzon JL, Walsh NP. Saliva indices track hypohydration during 48 h of fluid restriction or combined fluid and energy restriction. Arch Oral Biol. Walsh NP, Laing SJ, Oliver SJ, Montague JC, Walters R, Bilzon JL. Saliva parameters as potential indices of hydration status during acute dehydration. Walsh NP, Montague JC, Callow N, Rowlands AV. Saliva flow rate, total protein concentration and osmolality as potential markers of whole body hydration status during progressive acute dehydration in humans. Cheuvront SN, Ely BR, Kenefick RW, Sawka MN. Biological variation and diagnostic accuracy of dehydration assessment markers. Ben-Aryeh H, Roll N, Lahav M, Dlin R, Hanne-Paparo N, Szargel R, et al. Effect of exercise on salivary composition and cortisol in serum and saliva in man. J Dent Res. Ljungberg G, Ericson T, Ekblom B, Birkhed D. Saliva and marathon running. Scand J Med Sci Sports. Sollanek KJ, Kenefick RW, Walsh NP, Fortes MB, Esmaeelpour M, Cheuvront SN. Assessment of thermal dehydration using the human eye: what is the potential? J Therm Biol. Ungaro CT, Reimel AJ, Nuccio RP, Barnes KA, Pahnke MD, Baker LB. Non-invasive estimation of hydration status changes through tear fluid osmolarity during exercise and post-exercise rehydration. Holland JJ, Ray M, Irwin C, Skinner TL, Leveritt M, Desbrow B. Tear osmolarity is sensitive to exercise-induced fluid loss but is not associated with common hydration measures in a field setting. J Sports Sci. Owen JA, Fortes MB, Rahman SU, Jibani M, Walsh NP, Oliver SJ. Hydration marker diagnostic accuracy to identify mild intracellular and extracellular dehydration. Duren DL, Sherwood RJ, Czerwinski SA, Lee M, Choh AC, Siervogel RM, et al. Body composition methods: comparisons and interpretation. J Diabetes Sci Technol. Schoeller D, Van Santen E, Peterson D, Dietz W, Jaspan J, Klein P. Total body water measurement in humans with 18O and 2H labeled water. Lukaski HC, Johnson PE. A simple, inexpensive method of determining total body water using a tracer dose of D2O and infrared absorption of biological fluids. Al-Ati T, Preston T, Al-Hooti S, Al-Hamad N, Al-Ghanim J, Al-Khulifi F, et al. Total body water measurement using the 2 H dilution technique for the assessment of body composition of Kuwaiti children. Public Health Nutr. Fields D, Goran MI, McCrory MA. Body-composition assessment via air-displacement plethysmography in adults and children: a review. Gerner B, McCallum Z, Sheehan J, Harris C, Wake M. Survey and audit. J Paediatr Child Health. CORP: improving the status quo for measuring whole body sweat losses. Maughan RJ, Shirreffs SM, Leiper JB. Errors in the estimation of hydration status from changes in body mass. Leiper JB, Pitsiladis Y, Maughan RJ. Comparison of water turnover rates in men undertaking prolonged cycling exercise and sedentary men. Int J Sports Med. Cheuvront SN, Carter R III, Montain SJ, Sawka MN. Daily body mass variability and stability in active men undergoing exercise-heat stress. Montain SJ, Coyle EF. Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. McGee S, Abernethy WB III, Simel DL. Is this patient hypovolemic? González-Alonso J, Mora-Rodriguez R, Below PR, Coyle EF. Dehydration markedly impairs cardiovascular function in hyperthermic endurance athletes during exercise. Cheuvront SN, Ely BR, Kenefick RW, Buller MJ, Charkoudian N, Sawka MN. Hydration assessment using the cardiovascular response to standing. Armstrong LE, Ganio MS, Klau JF, Johnson EC, Casa DJ, Maresh CM. Novel hydration assessment techniques employing thirst and a water intake challenge in healthy men. Appl Physiol Nutr Metab. Young AJ, Sawka MN, Epstein Y, DeCristofano B, Pandolf KB. Cooling different body surfaces during upper and lower body exercise. Greenleaf JE, Morimoto T. Mechanisms controlling fluid ingestion: thirst and drinking. |
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et al. Westerblad, Håkan, David G. Allen, and Jan Lännergren. Jeukendrup, Asker, and Michael Gleeson. The Effects of Hydration on Athletic Performance Despite the commonly known importance of water in our bodies, many athletes do not seriously consider the effects of hydration during and after athletic performance.
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This requires a refractometer to measure the density of urine relative to the density of water. In dehydrated states, the specific gravity of urine exceeds 1.
Normal urine specific gravity ranges from 1. Urine color can be another method to determine hydration status. However, taking B-complex vitamins or a multivitamin can cause urine to have a bright yellow or even orange color and may not indicate dehydration.
Thirst can also be an indice of hydration status. Too much water Can you drink too much water? It is possible to drink too much water too fast and develop a condition called hyponatremia.
It should be noted that this happens very rarely in athletes and dehydration is more common. Finally, hydration is highly variable from athlete to athlete necessitating the need for individualized hydration plans. References: Armstrong LE. Assessing hydration status. The elusive gold standard.
J Am Coll Nutr. Follow these guidelines from trainers at the Sanford Sports Performance Lab. Proper hydration starts before you hit the court, field or gym. Start off your training sessions or competitions with all the fluids you need to perform safely and at your best.
The goal is to have regular urinations that are light yellow in color. Adults should drink about 6 to 12 oz. of water or sports drink every 15 to 20 minutes. One mouthful of water is about one ounce. Sports drinks provide water, as well as electrolytes and carbohydrates. Electrolytes help regulate the balance of fluids in your body, making them essential for hydration.
Drinking a sports drink helps replenish the electrolytes you lost while sweating. Carbs serve as a fuel source to help you maintain activity without hitting a wall.
Journal of the International Pedformance of Sports Nutrition sporrts 17 perforkance, Article number: 52 Cite this article. Metrics details. Despite a Oral diabetes treatment body of soorts, no Hydrahion best Anti-aging skincare routine guidelines Oral diabetes treatment for the assessment of hydration in athletes. Body water is stored in and shifted between different sites throughout the body complicating hydration assessment. This review seeks to highlight the unique strengths and limitations of various hydration assessment methods described in the literature as well as providing best practice guidelines. There is a plethora of methods that range in validity and reliability, including complicated and invasive methods i. REGISTER FOR KABUKI EDUCATION WEEK. Kabuki Mack Lite Clamps. Adn very metircs people Holistic allergy remedies direct attention to their individual hydration requirements. Here are a few facts that should make you reconsider the significant role of hydration in athletic performance. But I want to be clear about something, proper hydration is not about water consumption alone.
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