Andrew Jagim, Ph.D, CSCS
To unlock better performance, consider the humble beverage water. It is often one of the most overlooked and underappreciated ergogenic aids in today’s world of sports. The body is made up of ~70% water, which makes hydration a vital component for success-- not only during but before and after exercise as well. Dehydration can limit performance without the proper precautions, especially in hot and humid environments. Sweat is the primary means by which body water is lost during exercise; sweat rates for exercising individuals can average anywhere from 0.8 to 1.4 liters / hour. It’s been shown that a body weight loss of only 2% can result in a 22% decrease in endurance capacity. Failure to rehydrate during or after exercise leaves an individual more susceptible to heat illnesses such as cramps, heat stroke, and heat exhaustion.
Several strategies can help prevent dehydration and minimize decreases in performance. Before exercise, athletes should drink 0.5 liters of fluids 1 to 1.5 hours before competition. The thirst mechanism should not be used as a true indicator of a need for fluids because by the time the athlete feels thirsty, he or she has already lost 1.5 to 2.0 liters of water. Athletes should also avoid products that promote diuresis (water loss), such as caffeine-containing beverages. If possible, fluids should be cool (59 ºF to 72 ºF) and flavored to increase palatability. While exercising, athletes should aim to consume 6-8 oz. of fluids every 10-15 min (~1 L / hour to ensure full hydration). During bouts lasting more than an hour, drinking a beverage containing carbohydrates and electrolytes can help. Research has shown that consuming carbohydrate- and electrolyte-rich beverages can increase time-to-exhaustion and improve performances. Athletes who have high sweat rates or who are exercising in hot humid environments may also benefit from consuming 0.5-0.7 grams / liter of water to help improve fluid retention and replace lost electrolytes. For every 1 pound of body weight lost as sweat, athletes should consume 3 cups of water after exercise to replace the lost fluids, or 2 12-oz glasses.
Endurance athletes aren’t the only ones who can benefit from being adequately hydrated. Research shows that cellular hydration is important for resistance training individuals seeking gains in muscular strength and lean mass. The theory is that, by increasing the volume within a muscle cell, protein breakdown may decrease while synthesis may increase. Therefore everyone participating in athletics should take extra precautions to ensure that they are properly hydrated not only during competition but throughout the day as well. Lock in optimal performance by planning ahead and having water available to prevent dehydration.
For those interested in further reading:
Kreider, RB., Almada, AL., Antonio, J., Broeder, C., Earnest, C., Greenwood, M., Incledon, T., Kalman, DS., Kleiner, SM., Leutholtz, B., Lowery, LM., Mendel, R., Stout, JR., Willoughby, DS., Ziegenfuss, TN. 2004. ISSN Exerise & sport nutrition review: Research & recommendations. Sports Nutrition Review Journal. 1 (1), pp. 1-44.
Benardot, D. 2006. Advanced sports nutrition. Human Kinetics. Champaign, IL.