How to Avoid Heat Exhaustion During Exercise

Woman bending over due to heat exhaustion while exercising outdoors

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Athletes are especially prone to heat exhaustion and other heat illness, such as heat stroke, heat cramps, 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, especially when you have not been replenishing fluids and salts.

Heat exhaustion occurs when the body becomes overwhelmed by heat and the sweat response stops working properly. If you are in a humid environment, sweat may not be enough to cool your body.

Signs and Symptoms

The following are the most common signs and symptoms of heat exhaustion:

  • Heavy sweating
  • Pale, cool and moist skin
  • Fast and weak pulse
  • Nausea
  • Muscle cramps
  • Dizziness
  • Weakness
  • Headache
  • Tiredness
  • Fainting


If you recognize the symptoms of heat exhaustion, take the following actions:

  • Stop activities and rest.
  • Seek shade, shelter, or a cool room (air-conditioned if possible)
  • Drink cool, non-alcoholic beverages.
  • Take a cool shower or bath or splash yourself with cool water. Soak a bandana or your hat in cool water and place it on your head. Place a cold, wet towel around your neck.
  • Move to an air-conditioned room.
  • Remove extra clothing.

Seek medical attention if your symptoms are severe, are getting worse, or last longer than one hour.

Heat Exhaustion vs. Heat Stroke

If heat exhaustion is left untreated, it may lead to heat stroke, which is a medical emergency that requires immediate treatment. In heat stroke, the body is no longer able to maintain temperature control and your internal temperature rises rapidly to a dangerous level. Your temperature rises to above 103 and you have stopped sweating. Your skin is red, hot, and dry. During heat stroke, the neurological system is affected and can cause odd behavior, delusions, hallucinations, and eventually can lead to seizures, coma, and death.


It is easier to prevent heat illness than to treat it once symptoms develop. Follow these tips to minimize your risk of developing heat exhaustion:

  • Check the heat index before outdoor exercise in hot weather. The American College of Sports Medicine recommends canceling competitions and continuous outdoor activity at a heat index of 82, and all outdoor athletic activities at a heat index over 90.
  • 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 (16 to 20 ounces/hour).
  • Avoid exercising during the hottest time of day—train closer to sunrise or sunset.
  • Wear light, loose clothing so sweat can evaporate.
  • Invest in some clothes made with CoolMax, Drymax, Smartwool, polypropylene, or other technical athletic fibers. 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 the 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.

A Word From Verywell

It can be distressing or embarrassing to have to stop your workout or race because you are experiencing the symptoms of heat illness. But heat illness can go from mild symptoms to life-threatening quickly if you don't seek relief. It's not worth the risk (and expense) of an ambulance ride to the hospital. Be aware of the signs in yourself and your workout partners and encourage each other to stay safe.

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Article Sources
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  • Frequently Asked Questions (FAQ) About Extreme Heat. Centers for Disease Control and Prevention.

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