What to Drink for Proper Hydration During Exercise
Updated on June 24, 2019
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Staying hydrated is essential for everyone, but athletes have an even greater need to drink and replace fluids during exercise. Water is the most important nutrient for life and has many important functions including regulating temperature, lubricating joints and transporting nutrients and waste throughout the body.
Hydration During Exercise
Staying hydrated is particularly important during exercise. Adequate fluid intake is essential to comfort, performance, and safety. The longer and more intensely you exercise, the more important it is to drink the right kind of fluids.
Dehydration Decreases Performance
Studies have found that athletes who lose as little as two percent of their body weight through sweating have a drop in blood volume which causes the heart to work harder to circulate blood. A drop in blood volume may also lead to muscle cramps, dizziness, fatigue, and heat illness including:
Heat Stroke
Common causes of dehydration:
Inadequate fluid intake
Excessive sweating
Failure to replace fluid losses during and after exercise
Exercising in dry, hot weather
Drinking only when thirsty
What Should Athletes Drink?
Because there is wide variability in sweat rates, losses and hydration levels of individuals, it is nearly impossible to provide specific recommendations or guidelines about the type or amount of fluids athletes should consume.
Finding the right amount of fluid to drink depends upon a variety of individual factors including the length and intensity of exercise and other individual differences. There are, however, two simple methods of estimating adequate hydration:
Monitoring urine volume output and color. A large amount of light-colored, diluted urine probably means you are hydrated; dark colored, concentrated urine probably means you are dehydrated.
Weighing yourself before and after exercise. Any weight lost is likely from fluid, so try to drink enough to replenish those losses. Any weight gain could mean you are drinking more than you need.
How Athletes Lose Water
High altitude. Exercising at altitude increases your fluid losses and therefore increases your fluid needs.
Temperature. Exercising in the heat increases your fluid losses through sweating and exercise in the cold can impair your ability to recognize fluid losses and increase fluid lost through respiration. In both cases, it is important to hydrate.
Sweating. Some athletes sweat more than others. If you sweat a lot you are at greater risk for dehydration. Again, weigh yourself before and after exercise to judge sweat loss.
Exercise Duration and Intensity. Exercising for hours (endurance sports) means you need to drink more and more frequently to avoid dehydration.
To find the correct balance of fluids for exercise, the American College Of Sports Medicine suggests that "individuals should develop customized fluid replacement programs that prevent excessive (greater than 2 percent body weight reductions from baseline body weight) dehydration. The routine measurement of pre- and post-exercise body weights is useful for determining sweat rates and customized fluid replacement programs. Consumption of beverages containing electrolytes and carbohydrates can help sustain fluid-electrolyte balance and exercise performance."
According to the Institute of Medicine, the need for carbohydrate and electrolytes replacement during exercise depends on exercise intensity, duration, weather, and individual differences in sweat rates.
They write, "fluid replacement beverages might contain ~20–30 meqILj1 sodium (chloride as the anion), ~2–5 meqILj1 potassium and ~5–10% carbohydrate." Sodium and potassium are to help replace sweat electrolyte losses, and sodium also helps to stimulate thirst. Carbohydrate provides energy for exercise over 60-90 minutes. This can also be provided through energy gels, bars, and other foods.
What About Sports Drinks?
Sports drinks can be helpful to athletes who are exercising at a high intensity for 60 minutes or more. If you find yourself exercising in extreme conditions over 3 or 5 hours (a marathon, Ironman or ultramarathon, for example) you may likely want to add a complex sports drink with electrolytes.
Fluids supplying 60 to 100 calories per 8 ounces help to supply the needed calories required for continuous performance. It's really not necessary to replace losses of sodium, potassium and other electrolytes during exercise since you're unlikely to deplete your body's stores of these minerals during normal training.
General Guidelines for Fluid Needs
While specific fluid recommendations aren't possible due to individual variability, most athletes can use the following guidelines as a starting point and modify their fluid needs accordingly.
Hydration Before Exercise
Drink about 15-20 fl oz, 2-3 hours before exercise
Drink 8-10 fl oz 10-15 min before exercise
Hydration During Exercise
Drink 8-10 fl oz every 10-15 min during exercise
If exercising longer than 90 minutes, drink 8-10 fl oz of a sports drink (with no more than 8 percent carbohydrate) every 15 - 30 minutes.
Hydration After Exercise
Weigh yourself before and after exercise and replace fluid losses.
Drink 20-24 fl oz water for every 1 lb lost.
Consume a 4:1 ratio of carbohydrate to protein within the 2 hours after exercise to replenish glycogen stores.
Drinking too Much Water
Although rare, athletes can drink too much water and suffer from hyponatremia (water intoxication). Drinking excessive amounts of water can cause a low concentration of sodium in the blood—a serious medical emergency.
https://www.verywellfit.com/what-to-drink-for-proper-hydration-during-exercise-3120424