Heat exhaustion: First aid

Updated: 2022-04-15

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
• Faintness
• Dizziness
• Fatigue
• Weak, rapid pulse
• Low blood pressure upon standing
• Muscle cramps
• Nausea or vomiting
• Headache
• 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:

• Fainting
• Agitation
• Confusion
• Seizures
• Inability to drink
• Core body temperature — measured by rectal thermometer — of 104 F (40 C) (heatstroke)