According to the National Athletic Trainers' Association (NATA), Research shows that relying on thirst may cause athletes to underestimate fluid needs and replace on average only about 50% of the fluid lost in sweat. Therefore, the NATA recommends athletes drink on a schedule based on their individual sweat rate, regardless of thirst, to ensure that they are replacing sweat losses.

NATA recently convened an Inter-Association Task Force comprised of 18 sports medicine groups and injury prevention and health professional organizations to release an Exertional Heat Illnesses Consensus Statement.  The Consensus Statement, which applies to activity at all levels of intensity, states:

THIRST IS NOT ENOUGH: There is scientific research to support the idea that thirst is not an optimal way to determine when and how much an athlete should drink. By the time an athlete is thirsty, they are already somewhat dehydrated and in most cases will not drink enough to fully replace the fluids lost in sweat.

TO BE SAFE, KNOW YOUR SWEAT RATE: Rather than relying on thirst or simply drinking as much as you can tolerate (which can also be dangerous), knowing how much you sweat is the best way to determine hydration needs. To figure out how much you sweat, weigh yourself before and after exercise. The weight you lost in ounces represents fluid and that amount is how much should be consumed (in total) before, during and after exercise to adequately replace sweat and keep the body balanced.

REPLACE FLUIDS & ELECTROLYTES LOST: Optimal hydration is the replacement of fluids and electrolytes based on individual needs.  Drinking a sports drink helps replace the key electrolytes lost in sweat.

For more information, please visit the National Athletic Trainers' Association website.

10 Ways to Help Athletes Stay Safe in Intense Heat

1. ALLOW FOR ACCLIMATION – While it can take 10-14 days for an athlete’s body to adapt to the heat, acclimation should start two weeks before team practices begin. An athlete should start with 15-20 minutes of continuous exercise outside in the heat, and add 5-10 minutes each day.1
   
   
2. ADOPT REHYDRATION STRATEGY - Hydration helps reduce an athlete’s risk of heat illness and can help the athlete maintain a high level of performance. Proactive steps athletes can take to avoid dehydration include:
   
   • Weigh in and out before and after activity
   • Drink enough fluid to minimize weight loss - for each pound (16 oz.) that is lost, he or she may need to consume 20 ounces after athletic activity to fully rehydrate.
   • Check urine. If it’s like pale lemonade, that’s a sign of good hydration.


3. DRINK UP – Athletes should drink enough fluid to prevent dehydration without over-drinking. Flavored, cold, lightly salted sports drinks like Gatorade are important because sodium helps maintain the physiological desire to drink and helps retain the fluid consumed.
   
   
4. BUDDY UP AND KNOW THE SIGNS – Encourage athletes to buddy up with a teammate and watch out for each other when it’s hot and humid. They should know the signs and symptoms of heat illness which can include:
   • Nausea
   • Headache
   • Weakness
   • Fainting
   • Poor concentration
   • Personality change
   • Flushed skin
   • Light headedness
   • Loss of muscle coordination
   • Fatigue
   • Vomiting


5. COOL THE BODY – If experiencing heat illness, an athlete should take steps to cool the body, including lying in a cool place with legs elevated, applying cool, wet towels to the body and drinking cool fluids.
   
   
6. BE FLEXIBLE - An important step in avoiding heat illness is adjusting practice or game length and intensity to the environmental conditions. If possible, athletes should avoid strenuous and high intensity activities during the warmest time of day (10 am – 4 pm).
   
   
7. DRESS FOR THE WEATHER – Keeping cool in hot weather means being mindful of appropriate clothing and equipment that can help evaporate heat from the body:
   • Wear light-colored clothing
   • Wear t-shirts and shorts, not pads
   • Remove helmets when not active
   • Avoid wearing excess clothing
   • Change sweat–soaked clothing frequently


8. FIND TIME FOR RECOVERY – Rest and recovery are an essential part of avoiding heat illness. Athletes should work in times for breaks when active throughout the day, attempt to get six to eight hours of sleep a night and sleep in a cool environment, if possible.
   
   
9. MAINTAIN A HEALTHY DIET – Athletes need to think about fueling before, during and after physical activity. He or she should be fully hydrated with fluids and fueled with foods that contain electrolytes to maintain fluid levels. Fluids lost through sweat and breathing should be replaced by fluid consumption including during workouts, practices and games (physical activity).
   
   
10. HAVE AN EMERGENCY PLAN - Have a plan to contact medical professionals in an emergency. Also keep a “cool pool” or ice bath nearby so medical personnel can choose to immerse athletes suffering from heat stroke if necessary.

1 Maughan RJ and Murray R. Sports Drinks: Basic Science and Practical Aspects, Boca Raton, FL: CRC Press, 2001; 7-8: 183-224.