Prevent Heat Illness When Exercising in Hot Weather

Tips for preventing heat stroke, heat exhaustion, heat rash and dehydration

avoid heat illness during exercise
avoid heat illness during exercise. Blend Images - Priscilla Gragg/Brand X Images/Getty Images

Athletes are especially susceptible to heat-related illness such as dehydration, heat exhaustion, and heat stroke while exercising in hot weather. Most serious heat illness in athletes can be prevented by following some basic guidelines and heeding the warning signs and symptoms. However, if these warning signs are ignored, they may progress into a life-threatening heat emergency.

Common Heat-Related Illness

Prevent Heat-related Illness

Most forms of heat illness can be avoided by following basic prevention guidelines. Even so, it's essential for athletes and coaches to know the warning signs of a developing heat-related emergency and understand the level of severity of each condition. See: Heat Illness - Symptoms and Severity

Normally, our body temperature is regulated by sweating. A number of factors can limit the sweat response, including intense exercise in high temperatures or high humidity, age, obesity, fever, dehydration, illness, medications and alcohol. When an athlete develops a heat illness, it usually occurs after several hours of exertion and excessive sweating that leads, first to dehydration, and then to electrolyte imbalances.

To prevent heat-related illness, follow these precautions:

  • Drink the Right Amount of the Right Fluids
    Finding the right amount of fluid to drink depends on upon a variety of individual factors including the length and intensity of exercise and other individual differences. There are, however, two simple methods of estimating adequate hydration.
  • Replace Lost Electrolytes
    Sweat leeches salt and minerals from the body. It's important to maintain sodium and electrolyte levels if you are sweating profusely and exercising more than 90 minutes. The easiest way to replace these are with salty foods or sports drinks.
  • Wear Appropriate Clothing
    Choose lightweight, light-colored, loose-fitting clothing. In the hot sun, a hat and sunscreen are helpful. Wear light, loose-wicking clothing so sweat can evaporate. Better yet, invest in some clothes made with CoolMax®, Drymax®, Smartwool or polypropylene. These fibers have tiny channels that wick the moisture from your skin to the outer layer of the clothing where it can evaporate more easily.
  • Use Sunscreen and Avoid Sunburn
    Sunburn decreases your ability to cool yourself and causes fluid loss. Use sunblock with SPF 15 or higher. Wear a hat that provides shade and allows ventilation.
  • Acclimate to the Heat
    You will have a greater tolerance for exercise in the heat if you become accustomed to it slowly over one to two weeks. If traveling to a hotter climate, allow several days to acclimate before doing intense exercise. Avoid exercise during the hottest time of day; train closer to sunrise or sunset.
  • Use Common Sense
    Avoid hot foods, alcohol and heavy foods that increase your core temperature. If you feel any headaches, fatigue or irritability or notice your exercise performance decreasing, stop exercising and cool off.

Remember, it is easier to prevent heat illness than to treat it once symptoms develop. Always be prepared for changing weather conditions and stop your activity and rest at the first sign of trouble.


The Centers for Disease Control and Prevention (CDC), Extreme Heat: A Prevention Guide to Promote Your Personal Health and Safety, 2006.

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