Athletes have many factors to consider when it comes to improving performance, and a critical aspect is hydration. The human body is about 60 percent water, and water takes part in several chemical reactions within the body (Gropper et al. 2008). Water also allows for transport of nutrients, is essential for maintaining the body’s temperature, and is necessary for most other physiological processes (Dunford and Doyle 2012). Physical activity leads to additional physiological stress, further increasing the need for adequate hydration. With numerous hydration options available to athletes, it is necessary to examine the existing research and recommendations to promote proper hydration for athletic participation.
The goal for hydration status is euhydration, which is a sufficient volume of water to meet the body’s requirements (Dunford and Doyle 2012). Deviations from this condition include hypohydration and hyperhydration, and both can lead to detrimental symptoms (Sawka et al. 2001). Hypohydration occurs by the process of decreasing total body water, or dehydration. Exercise in the dehydrated state leads to several unfavorable symptoms due to the increase it causes in heart rate, core temperature, and perceived exertion responses (Sawka and Coyle 1999). Dehydration, particularly when greater than two percent, can decrease cognitive and exercise performance. The greater the dehydration level, the greater the impairment in functioning (Cheuvront et al. 2003). Hyperhydration involves overdrinking in combination with an agent that binds water. Though sometimes promoted as a means for improving exercise performance, this practice has many risks and is generally not recommended.5 Another concern in this realm is hyponatremia, a condition in which plasma sodium levels are decreased. Symptoms include headache, fatigue, confusion, seizures, coma, and even death (Zambraski 2005).
As has been demonstrated, excessive deviations from fluid balance can have detrimental effects on health and athletic performance. Fluid balance is comprised of fluid loss and fluid gains of the body. The primary routes of fluid losses include respiratory, renal, gastrointestinal, and sweat. In regard to fluid gains or replacement for athletes, recommendations have been developed by the American College of Sports Medicine.
Numerous beverages are promoted as being beneficial for athletes for fluid replacement purposes. Beverages and products often touted include water, sports beverages (Gatorade, PowerAde, etc.), protein drinks, milk, chocolate milk, and caffeinated beverages. Water is likely the best option for before and during exercise when activities are less than sixty minutes. For exercise of longer duration or in extreme environmental conditions, electrolytes and carbohydrates may need to be replaced during exercise in addition to fluid losses. Caffeinated beverages may have potential stimulatory benefits, and do not appear to excessively negatively affect hydration status when used in appropriate amounts. In the post exercise period, recovery beverages such as chocolate milk, protein drinks, and sports beverages may be viable options (Dunford and Doyle 2012). Regardless of the products selected for the means of hydration, athletes should make maintaining appropriate hydration levels a priority in order to maximize their health and athletic performance.
Gropper, S. S., J. L. Smith, and J. L. Groff. 2008. Advanced Nutrition and Human Metabolism, 5th Edition. Thompson Wadsworth, Belmont, California, USA.
Dunford, M. and J. A. Doyle. 2012. Nutrition for Sport and Exercise, 2nd edition. Wadsworth, Belmont, California, USA.
Sawka, M. N., S. J. Montain, and W. A. Latzka. 2001. Hydration effects on thermoregulation and performance in the heat. Comparative Biochemistry and Physiology Part A 128: 679-690.
Sawka, M. N. and E. F. Coyle. 1999. Influence of body water and blood volume on thermoregulation and exercise performance in the heat. Exercise and Sports Science 27: 167-218.
Cheuvront, S. N., E. M. Haymes, and M. N. Sawka. 2003. Fluid balance and endurance exercise performance. Curr Sports Med Rep 2: 202-208.
Zambraski, E. J. 2005. The renal system. Pages 521-532 in C. M. Tipton, M. N. Sawka, C. A. Tate, and R. L. Terjung. American college of sports medicine: Advanced exercise physiology. Lippincott, Williams and Wilkins, Baltimore, Maryland, USA.
American College of Sports Medicine, Sawka M. N., L. M. Burke, E. R. Eichner, R. J. Maughan, S. J. Montain, and N. S. Stachenfeld. 2007. American college of sports medicine position stand: Exercise and fluid replacement. Medicine
Articles by Jamie Saunders.