Heat Exhaustion: What It Is and How It Can Be Prevented

Heat exhaustion is a syndrome that occurs when the body overheats in response to external factors, such as hot weather.1,2 Everyone is susceptible, but some people are at a higher risk. People at exceptional risk are those who have physical jobs requiring strenuous activities or use of heavy protective clothing in hot environments, athletes who participate in strenuous sports, people above the age of 65, and people inclined to sunburn.2 Instances of heat exhaustion are expected to increase over time with climate change.3

Heat Exhaustion vs. Heat Stroke

If heat exhaustion is left untreated, it can quickly progress into heat stroke, which is a potentially lethal condition. Signs that heat exhaustion has turned into heat stroke are high body temperature (103oF or more); hot, red, dry, or damp skin; a fast, strong pulse; confusion; and losing consciousness.5

Symptoms of Heat Exhaustion

  • A sudden drop in blood pressure when moving from a sitting to a standing position2
  • Dizziness or lightheadedness, feeling faint
  • Heavy sweating
  • Fast, weak pulse4
  • Muscle cramps5
  • Headache
  • Nausea or vomiting
  • Cold, pale, clammy skin5


You can take deliberate steps to prevent heat exhaustion. A key act of prevention is being aware of weather conditions, especially at the end of spring and the beginning of summer. The risk of heat-related illness is highest when people have not yet acclimatized to the heat.6 If the heat index is high, try to stay indoors in an air-conditioned area. If you cannot avoid being outside during extremely hot weather, try to restrict strenuous physical activity to the cooler periods of the day, such as early morning and early evening, and seek out air-conditioned buildings if possible. If you are prone to sunburn, wear sunscreen, UV protective clothing, and a hat. Keeping the sun off your face can help control body temperature.2 Stay hydrated and wear light, breathable clothing.7 Finally, awareness of the signs and symptoms of heat-related illnesses is crucial. This way, you can be proactive and seek treatment sooner rather than later.


Strategies that have a cooling effect on the body followed by close monitoring are best for treating heat exhaustion.4 This can be done by moving the person to a shady space or into an air-conditioned building. Placing ice packs or cool, wet towels on the forehead, wrists, the back of the neck, or under the arms can be particularly effective.2 If the person is wearing tight or heavy clothing, quickly remove it. Finally, have the person drink a cool beverage to rehydrate.

If You Suspect Heat Exhaustion or Heat Stroke

Heat exhaustion is a life-threatening condition that requires immediate neurological care.3 With the proper treatment, the person should make a full recovery within a few hours.6 If symptoms do not improve or if they worsen within an hour, seek medical attention immediately or call 911.


  1. Heat exhaustion: First aid. Mayo Clinic website. https://www.mayoclinic.org/first-aid/first-aid-heat-exhaustion/ basics/art-20056651. Updated March 31, 2020. Accessed June 3, 2020.
  2. Whelan C. Understanding Heat Exhaustion: Symptoms, Tips for Self-Care, and More. https://www.healthline.com/ health/heat-exhaustion. Updated April 21, 2017. Accessed June 2, 2020.
  3. Peiris AN, Jaroudi S, Heat Stroke NR. JAMA. 2017;318:2503.
  4. Hifumi T, Kondo Y, Shimizu K, et al. Heat stroke. J Intensive Care. 2018;6.
  5. Warning Signs and Symptoms of Heat-Related Illness. Center for Disease Control and Prevention website. https://www.cdc.gov/disasters/extremeheat/warning.html. Updated September 1, 2017. Accessed June 2, 2020.
  6. Groot E, Abelsohn A, Moore K. Practical strategies for prevention and treatment of heat-induced illness. Can Fam Physician. 2014;60(8):729–e394.
  7. Hajat S, O’Connor M, Kosatsky T. Health effects of hot weather: from awareness of risk factors to effective health protection. Lancet. 2010;375(9717):856–63. 

Latest Recipes

Sign up for NHR’s FREE E-Newsletter!

          • Receive notifications when a new issue of NHR is available
          • Get free recipes, tips on healthy living, and the latest health news

Subscribe to NHR Print for only $18 a year!

Get unlimited access to content plus receive 6 eye-appealing, information-packed print issues of NHR delivered to your mailbox.