Recognizing And Preventing Dehydration In Athletes
- Volume 17 - Issue 12 - December 2004
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Sports drinks appear to outperform water in preventing dehydration, especially in young athletes. A study that offered water, flavored water and a sports drink to active children ages 9 to 12 showed they drank 90 percent more of the sports drink and stayed better hydrated than when drinking plain water. Sports drinks served cold (50º to 59ºF is recommended) have flavor (sweetness) and sodium that encourage athletes to drink more.
When fluids have the correct mixture of carbohydrates and electrolytes, athletes absorb them quicker into the bloodstream and the fluids help refuel muscles and speed rehydration. Carbohydrates also aid in performance by facilitating an increased feel of energy for power and endurance enhancement. Though carbohydrate concentrations greater than 8 percent increase the rate of carbohydrate delivered to the body, they compromise the rate of fluid emptying from the stomach and absorbed from the intestine.
What Drinks Should Athletes Avoid?
Fruit juices, carbohydrate gels, soda and sports drinks that have carbohydrate concentrations greater than 8 percent are therefore not recommended during an exercise session as the sole beverage. Most carbohydrate forms such as glucose, sucrose and glucose polymers are suitable and the absorption rate is maximized when multiple forms are consumed simultaneously. Fructose ingestion should be limited since it may cause gastrointestinal distress.
Substances to be avoided include caffeine and alcohol, which increase urine output and reduce fluid retention, and carbonated beverages, which reduce voluntary fluid intake due to stomach fullness.
Consider adding sodium chloride to fluid replacement beverages for physical activity exceeding four hours or during the initial days of hot weather. This can offset the salt loss in sweat and minimize the medical problems associated with electrolyte imbalances such as muscle cramps and hyponatremia. Hyponatremia has been associated in sporting events with overhydration, both orally and IV, with hypotonic (relative to sweat) solutions. There have been reported cases in which individuals had been overhydrated with as much as 6 to 7 liters of free water. Given this, providing hydration beverages that contain a small amount of salt would be desirable and should cause no harm.
Dr. Caselli (pictured) is a staff podiatrist at the VA Hudson Valley Health Care System in Montrose, N.Y. He is also an Adjunct Professor at the New York College of Podiatric Medicine and a Fellow of the American College of Sports Medicine.
Dr. Brummer is in private practice with the Metropolitan Foot Group, New York City. He is an Associate of the American College of Foot and Ankle Surgeons.
1. Bar-Or O. Temperature regulation during exercise in children and adolescents. In Gisolfi C, Lamb DR (eds). Perspectives in Exercise and Sports Medicine, II, Youth, Exercise and Sport. Indianapolis, IN, Benchmark Press; 1989. pp 335-367.
2. Casa DJ, Armstrong LE, et. al. National Athletic Trainers’ Association Position Statement: Fluid Replacement for Athletes. J Athletic Training 35(2) 212-224, 2000
3. Noakes TD. Dehydration during exercise: what are the real dangers? Clinical Journal of Sports Medicine 5(2) 123-128, 1995
4. Stoddard DW. (2001) Hyponatremia or Hype? [Letter to the Editor] Phys Sportsmed 29(7) 2001
5. Wilk B, Bar-Or O. Effect of drink flavor and NaCl on voluntary drinking and hydration in boys exercising in the heat. J Appl Physiol 80: 1112-1117, 1996