Heat Exhaustion Symptoms and Treatment

Heat exhaustion is caused by an increase in core body temperature often coupled with fluid loss (dehydration). It's important to recognize heat exhaustion early and seek treatment as quickly as possible. It does not need to be hot outside for heat exhaustion to occur. Heat exhaustion can lead to heatstroke if not treated in time.

Young woman holding water bottle
Frank P Wartenberg / Getty Images


When your body's internal temperature rises, its normal response is to sweat and be cooled by evaporation. But if the humidity is high so sweat won't evaporate, or you are already dehydrated, you may not be able to cool your internal temperature fast enough and your core temperature rises. Heat exhaustion is one of the less severe conditions of heat illness. Heat illness includes heat cramps, heat exhaustion, heat syncope, and heat stroke. 


Everyone is at risk of heat exhaustion if they are in a hot environment, especially if they are not replacing the fluid and salt lost in sweat. These groups have a greater risk:

  • Infants and children from ages 0 to 4
  • Elderly adults
  • Obese people
  • People consuming alcohol/using drugs
  • People who take certain medications, including beta-blockers, antihistamines, anti-psychotics, and medication used for Parkinson's disease
  • People working or exercising in the heat, especially when the heat index is 90 F or more

Signs and Symptoms

The warning signs of heat exhaustion may include:

  • Weakness
  • Dizziness or fainting
  • Warm, moist, pale skin
  • Nausea and vomiting
  • Heavy sweating
  • Headache


If you recognize that you are having the early symptoms of heat exhaustion, use these self-care tips immediately:

  • Get into a cooler environment, preferably air-conditioned.
  • Drink cool beverages, which will help cool you down internally. However, do not drink alcoholic beverages. An electrolyte-replacement sports drink is often a good choice if you have been sweating, as you are losing salt as well as fluids.
  • Sponge yourself with cool water. People exercising or playing sports will often pour cold water on their head or soak a towel in cold water to apply to their necks. If available, take a cool shower.
  • Change into lightweight clothing that will allow perspiration to evaporate.

If You Are Assisting Someone

Use these strategies to help someone in trouble:

  • Stay safe. If the environment is hot enough for the victim to get overheated, then it's hot enough for the rescuers.
  • Follow universal precautions and wear personal protective equipment if you have it.
  • Make sure the person with heat exhaustion symptoms has an airway and is breathing. Follow the ABCs of first aid.
  • Move the person to a cooler environment immediately. The shade is better than the sun, air conditioning is better than outside, etc. The cooler the better.
  • Loosen or remove the person's clothing to encourage heat loss.
  • If the person is conscious and able to follow commands, give him cool, nonalcoholic fluids to drink to rehydrate.

When to See the Doctor

  • If your symptoms or that of the person you are assisting get worse or last longer than an hour, get medical help at an urgent care clinic or emergency room.

Signs of a Medical Emergency

  • If the person is unable to follow commands (unconscious) or is vomiting, call 911 immediately.
  • If the person has stopped sweating or is unconscious, he should be treated for heatstroke. Heat exhaustion can progress to heatstroke. This can lead to death or permanent disability and you should get emergency medical help.
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. State of California Department of Industrial Relations. What is heat illness?

  2. Centers for Disease Control and Prevention. Frequently asked questions (FAQ) about extreme heat.

  3. Cleveland Clinic. Heat illness.

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.