Fluid Replacement and Prevention of Heat Illness

Environmental Conditions
NASPE/NCAT Sport Injury Resource

The National Athletic Trainers’ Association (NATA) recommends the following practices regarding fluid replacement for athletic participation. For more information, log onto http://www.nata.org, then click on Publications > Position Statements.

1) Establish a routine for water or hydration consumption. Remember, by the time your athletes become thirsty, they are already dehydrated. Increase water breaks during practice. Instruct and require athletes to drink 7 to 10 fluid ounces every 10-20 minutes. Water is the more practical fluid to consume, however, if other types of sport drinks are used, make sure to read the label. The carbohydrate concentration should read below eight percent. Carbohydrate concentrations above 8% compromise the rate of fluid emptying from the stomach and absorbed from the intestine. Fruit juices, carbohydrate gels, sodas, and some sport drinks have carbohydrate concentrations higher than 8% and are NOT recommended during activity as the sole beverage. It is helpful to dilute prepared sports drinks if uncertain as to the carbohydrate levels. Discourage young athletes from drinking beverages containing caffeine or carbonation during activity. They can dehydrate the body by stimulating excess urine production, or decrease voluntary fluid intake.

2) Instruct athletes to drink plenty of water prior to and after practices and games. Two to three hours before activity, have athletes drink 17-20 ounces of water or sports drink such as Gatorade®. Approximately 10-20 minutes before the event, have them drink another 7-10 ounces of water or sports drink. Within two hours after activity or the game, youth should replace any weight loss from exercise. A guideline to follow includes drinking approximately 20-24 ounces of water or sports drink per pound of weight loss.

Other Heat Illness Prevention Guidelines:

  1. All athletes and coaches should be familiar with heat illness prevention, recognition, and treatment.

  2. Adapt athletes to exercising in heat gradually over 10-14 days (acclimatization).

  3. Educate athletes to maintain adequate hydration. Replace fluids between practices on the same day and on successive days to maintain less than a 2% change in body weight. Athletes exercising in hot conditions, especially during two-a-day practices, require extra sodium in fluid replacement drinks and/or diet.

  4. Check the environmental conditions before and during the activity, and adjust the practice schedule accordingly. Avoid practicing during the hottest part of the day (10 am to 5 pm) during extreme periods of heat and humidity. Modify activity/practice under high-risk conditions: (1) high temperature and humidity; (2) athletes susceptible to heat illnesses: over-weight and/or obese individuals, those in poor condition or who are sick, athletes wearing excessive or dark-colored clothing/equipment, athletes who take certain medications with a dehydrating effect.

  5. Plan adequate rest breaks. Fluid and rest breaks should be scheduled for all practices and scheduled more frequently as the heat and humidity rise (i.e., when temperature/humidity is extreme), allow for 5-10 minute rest and fluid breaks every 15 to 20 minutes and practice in shorts/loose-fitting mesh shirt with no equipment such as pads/helmet. As an example, a full football uniform prevents sweat evaporation from more than 60% of the body. A supply of cool water and/or sport drink should be readily available for all practices.

  6. Weigh at-risk athletes before and after practice to estimate the amount of body water lost during practice and to ensure a return to pre-practice weight before the next practice. In high heat/humidity conditions or during multiple practice schedules, all athletes’ weight should be monitored (pre and post-workout weights recorded).

  7. Ice should be available for active cooling in case of heat illness and to keep beverages cool.

  8. A tub (cold whirlpool) or “kiddie pool” full of cool water should be available when environmental conditions are immoderate.

  9. Make sure athletes receive 6-8 hours of sleep each night in a cool environment. eat a well-balanced diet, and maintain proper hydration. Implement rest periods at mealtime by allowing 2-3 hours for food, fluids, nutrients, and electrolytes (sodium and potassium) to move into the small intestine and bloodstream before the next practice.

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