Symptoms and Signs of Heat Exhaustion

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 3/11/2019

Doctor's Notes on Heat Exhaustion

Heat exhaustion is a condition that occurs when the body's cooling mechanism fails to maintain a normal core temperature and the body overheats. Causes of heat exhaustion can include strenuous work or exercise in a warm or hot environment, dehydration, alcohol intake, and wearing clothing that does not allow for evaporative cooling of the body.

Symptoms of heat exhaustion may include weakness, muscle cramps heavy sweating, headache, nausea, vomiting, weak and rapid pulse, thirst, clammy skin, dizziness, and elevated body core temperature (internal temperature, not skin temperature). Heat exhaustion can occur before the onset of heat stroke, which is a medical emergency. If there are signs or symptoms of heat stroke call 911 or get the person to a hospital’s emergency department immediately. Symptoms of heat stroke include that the body stops sweating, and the skin is hot and dry and sometimes reddish colored. Stroke-like symptoms including confusion, hallucinations, seizures, loss of consciousness, organ damage, coma, and death can occur in heat stroke if not treated promptly.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.