Heat exhaustion is one of the heat-related syndromes. These syndromes range in severity and seriousness from mild to potentially life-threatening. Other types of heat-related illnesses include heat rash, heat cramps, heat syncope and heatstroke.
Heat exhaustion can occur when your body loses too much water or salt — usually as a result of excessive sweating or dehydration. It can begin suddenly or happen over time, usually after working, exercising or playing in the heat.
Heat exhaustion signs and symptoms include:
- Cool, moist skin with goose bumps when in the heat
- Heavy sweating
- Weak, rapid pulse
- Low blood pressure upon standing
- Muscle cramps
- Nausea or vomiting
- Extreme thirst
- Mild confusion
- Decreased urine output
If you suspect heat exhaustion
Untreated, heat exhaustion can lead to heatstroke, which is a life-threatening condition. If you suspect heat exhaustion, take these steps immediately:
- Move the person out of the heat and into a shady or air-conditioned place.
- Lay the person down and elevate the legs and feet slightly.
- Remove tight or heavy clothing.
- Have the person sip chilled water, a decaffeinated sports drink containing electrolytes or other nonalcoholic beverage without caffeine.
- Cool the person by spraying or sponging with cool water and fanning.
- Monitor the person carefully.
Contact a health care provider if signs or symptoms worsen or if the person doesn't improve after taking first-aid measures.
Call 911 or your local emergency number if the person's condition gets worse, especially if he or she experiences:
- Inability to drink
- Core body temperature — measured by rectal thermometer — of 104 F (40 C) (heatstroke)
April 15, 2022
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- Ishimine P. Heat illness (other than heat stroke) in children. https://www.uptodate.com/contents/search. Accessed Feb. 24, 2022.
- Heat stress. Centers for Disease Control and Prevention. https://www.cdc.gov/niosh/topics/heatstress/. Accessed Feb. 24, 2022.
- Heat-related illnesses. American College of Emergency Physicians. https://www.emergencyphysicians.org/article/know-when-to-go/heat-related-illnesses. Accessed Feb. 24, 2022.
- Heat injury and heat exhaustion. American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/diseases--conditions/heat-injury-and-heat-exhaustion. Accessed Feb. 24, 2022.
- O'Connor FG, et al. Exertional heat illness in adolescents and adults: Management and prevention. https://www.uptodate.com/contents/search. Accessed Feb. 24, 2022.
- Hoecker JL (expert opinion). Mayo Clinic. March 2, 2022.