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Heat Exhaustion Symptoms and Prevention

How to prevent and treat heat exhaustion during exercise


Updated May 19, 2014

Prevent Heat Exhaustion

Prevent Heat Exhaustion

Photo (c) Ryan Pierse / Getty Images
Athletes are especially prone to heat exhaustion and other heat illness, such as heat stroke and dehydration, when exercising in hot and humid conditions. Taking precautions and recognizing the symptoms or early warning signs of heat exhaustion is essential if you exercise in hot weather.

What Is Heat Exhaustion?

Heat exhaustion is the body's response to dehydration and an excessive loss of water and salt through sweat. Heat exhaustion typically occurs after long periods of heat exposure. Heat exhaustion occurs when the body becomes overwhelmed by heat and the sweat response stops working properly.

Signs and Symptoms of Heat Exhaustion

The following are the most common signs and symptoms of heat exhaustion:
  • nausea
  • dizziness
  • weakness
  • headache
  • pale, cool and moist skin
  • fast and weak pulse
  • disorientation.
  • paleness
  • muscle cramps
  • tiredness
  • fainting

Heat Exhaustion vs. Heat Stroke

If heat exhaustion is left untreated, it may lead to heat stroke. The key difference between heat stroke and heat exhaustion is the presence of confusion and other mental status changes during heat stroke. During heat stroke, the neurological system is affected and can cause odd behavior, delusions, hallucinations, and eventually seizures or a coma.

At the first signs of heat exhaustion, you should stop activity and cool the body by seeking shade, shelter or a cool room, and drinking cold fluids.

Seek medical attention immediately if symptoms are severe.

Heat Exhaustion Treatment

If you recognize the symptoms of heat exhaustion, take the following actions:
  • Stop activities and rest
  • Drink cool, non-alcoholic beverages
  • Take a cool shower, or bath
  • Move to an air-conditioned room
  • Remove extra clothing

Learn More About: Exercise in the Heat

Preventing Heat Exhaustion

Follow these tips to minimize your risk of developing heat exhaustion:
  • If you are going to exercise in hot weather, it's important to acclimatize to the heat for about a week before beginning any intense exercise. This allows your body to gradually adapt to the heat.
  • Hydrate well before and during exercise and replace lost electrolytes such as sodium, potassium and magnesium with food or a sports drink (drink 16 to 20 oz/hour).
  • Avoid exercising during the hottest time of day; train closer to sunrise or sunset.
  • Wear light, loose 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 to prevent sunburn, which can limit the skin's ability to cool itself.
  • Wear a hat with a brim.
  • If you feel your abilities start to diminish, stop activity and seek out a cool shaded place.
  • Do not drink alcohol or beverages with caffeine before exercise because they increase the rate of dehydration.
  • Remember, it is easier to prevent heat illness than to treat it once symptoms develop.


The Centers for Disease Control and Prevention (CDC), Extreme Heat: A Prevention Guide to Promote Your Personal Health and Safety. http://www.bt.cdc.gov/disasters/extremeheat/heat_guide.asp, 2006.

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