Their research into hydration concluded that, in the early s, it was considered best practice to advise athletes to drink nothing, or as little as possible, during all athletic pursuits. Four small bottles for a long stage of the Tour, it is frowned upon to drink more.

Avoid drinking when racing, especially in hot weather. Drink as little as possible, and with the liquid not too cold. It is only a question of will power. The hypothesis was that this fatigue was often being caused by a combination of carbohydrate depletion, dehydration and electrolyte loss.

So a drink formulated with sugar, salts and water was developed and found to be remarkably effective. Image credit: Ethan McArthur via Unsplash Copyright free. Many of these studies appeared to demonstrate that dehydration was a serious performance limiter, especially during endurance sports in the heat.

It included the statement:. During exercise, athletes should start drinking early and at regular intervals in an attempt to consume fluids at a rate sufficient to replace all the water lost through sweating or consume the maximal amount that can be tolerated.

Other examples include the High Carb vs Low Carb diet debate and Cushioned, Supportive running shoes vs Barefoot Running. We struggle with grey areas, even though that tends to be where the answers to complicated questions often reside!

He uncovered a growing number of cases of hyponatremia - a sometimes fatal condition characterised by low blood sodium levels - in an increasing number of endurance athletes who had seemingly followed advice to drink as much as they could.

In this he suggests that hyponatremia has become a significant problem largely because of the marketing efforts of the sports drink industry. He makes the tragic point that there have been a number of preventable deaths from over-drinking and that these could have been avoided with more balanced messaging.

Image credit: Press and Journal ©. Because there is considerable variability in sweating rates and sweat electrolyte content between individuals, customized fluid replacement programs are recommended.

He argues, quite compellingly, that the human body is designed to optimize its own hydration levels so, if you drink to thirst, that is basically all you need to know about hydration.

End of story. This approach has merit in many circumstances. This is most likely to be the case during ultra-distance events, where total sweat losses can be significant over a long period of time, especially in the heat.

Maybe because of the human tendency towards tribalism, there are currently two opposing camps in hydration science. At the sharp end, it seems that opinion is moving towards a view that, whilst drinking to thirst is a sensible approach for shorter or lighter activities, during very long events in the heat, when total sweat and electrolyte losses are high, replenishment might need to be approached more proactively than would be the case in shorter bouts of activity.

Examples of the efficacy of this approach include this study by researchers in Spain, which showed faster racing times for athletes given salt supplements during a middle distance triathlon compared to a control group given placebos.

Drinking to thirst is likely to be a good approach in day to day life, or endurance training completed at a very low intensity. far more than I replace after my thirst response has kicked in, and so inevitably have to slow my speed as my blood volume continues to decline.

When drinking to thirst, I can lose Perhaps there are athletes whose thirst response provides a more reliable guide, but in my experience with both coaching and racing, drinking to a schedule, particularly in the first half of events, leads to vastly better performance outcomes.

Patel, MD, FAAFP, FACSM. Good hydration means getting the right amount of water before, during, and after exercise. Water regulates your body temperature and lubricates your joints.

It helps transport nutrients to give you energy and keep you healthy. You may feel tired, have muscle cramps, dizziness, or other serious symptoms.

If your urine is usually colorless or light yellow, you are most likely well hydrated. Dark yellow or amber-colored urine can be a sign of dehydration. There are no exact rules for how much water to drink while exercising, because everyone is different. You need to consider factors including your sweat rate, the heat and humidity in your environment, your clothing, and how long and hard you are exercising.

You may need to stay better hydrated if you have certain medical conditions, such as diabetes, heart disease, and cystic fibrosis. Some medications can act as diuretics, causing the body to lose more fluid. The American Council on Exercise has suggested the following basic guidelines for drinking water before, during, and after exercise:.

Athletes may want to measure how much fluid they lose during exercise to get a more specific measurement of how much water to drink 16 to 24 ounces of water for every pound of body weight lost. For most people, water is all that is needed to stay hydrated.

However, if you will be exercising at a high intensity for longer than an hour, a sports drink may be helpful. The calories, potassium, and other nutrients in sports drinks can provide energy and electrolytes to help you perform for a longer period of time.

Choose a sports drink wisely. They are often high in calories from added sugar and may contain high levels of sodium. Also, check the serving size. One bottle may contain several servings. If you drink the entire bottle, you may need to double or triple the amounts given on the nutrition facts label.

Some sports drinks contain caffeine. If you consume a sports drink that contains caffeine, be careful not to add too much caffeine to your diet. Caffeine may cause a diuretic effect on your body. This means that you may have to urinate more often.

Sugary drinks, such as juice and soda, are not healthy options for staying hydrated. Dehydration happens when you lose more fluid than you drink.

Dehydration can range from mild to severe. Symptoms of dehydration can include the following:. Symptoms of severe dehydration can include mental confusion, weakness, and loss of consciousness. You should get emergency medical attention immediately if you have any of these symptoms.

There are 3 stages of heat illness:. Symptoms of heat cramps include painful muscle spasms in the legs, stomach, arms, or back. Symptoms of heat exhaustion are more serious. They can include faint or weak feelings, nausea, headache, fast heartbeat, and low blood pressure.

The most serious heat-related illness is heatstroke. Symptoms can include high body temperature higher than °F , fast heartbeat, flushed skin, fast breathing, and possibly even confusion or delirium, loss of consciousness, or seizures.

You should get emergency medical attention immediately if you experience any of the symptoms of heatstroke. Untreated heatstroke can lead to death.

This depends on your body and the kind of activity you are doing. Talk to your family doctor if you have questions about the right amount of water to drink while exercising. You should see a doctor immediately if you have symptoms of dehydration, heat exhaustion, or heatstroke.

You should also see a doctor if you have symptoms of a rare condition called hyponatremia. These include confusion, headache, vomiting, and swelling of the hands and feet. American Council on Exercise: Healthy Hydration.

American Heart Association: Staying Hydrated — Staying Healthy. National Institutes of Health, MedlinePlus: Dehydration. Last Updated: June 2, This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.