Heat Stroke

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Heat stroke facts

  • Heat stroke is a form of hyperthermia in which the body temperature is elevated dramatically.
  • Heat stroke is a medical emergency and can be fatal if not promptly and properly treated.
  • Cooling the victim is a critical step in the treatment of heat stroke. Always notify emergency services immediately if heat stroke is suspected.
  • The most important measures to prevent heat strokes are to avoid becoming dehydrated and to avoid vigorous physical activities in hot and humid weather.
  • Infants, the elderly, athletes, and outdoor workers are the groups at greatest risk for heat stroke.

What is, and who is at risk for heat stroke?

Heat stroke is a form of hyperthermia or heat-related illness, an abnormally elevated body temperature with accompanying physical symptoms including changes in the nervous system function. Unlike heat cramps and heat exhaustion, two other forms of hyperthermia that are less severe, heat stroke is a true medical emergency that is often fatal if not properly and promptly treated. Heat stroke is also sometimes referred to as heatstroke or sun stroke. Severe hyperthermia is defined as a body temperature of 104 F (40 C) or higher.

The body normally generates heat as a result of metabolism, and is usually able to dissipate the heat by radiation of heat through the skin or by evaporation of sweat. However, in extreme heat, high humidity, or vigorous physical exertion under the sun, the body may not be able to sufficiently dissipate the heat and the body temperature rises, sometimes up to 106 F (41.1 C) or higher. Another cause of heat stroke is dehydration. A dehydrated person may not be able to sweat fast enough to dissipate heat, which causes the body temperature to rise.

Heat stroke is not the same as a stroke. "Stroke" is the general term used to describe decreased oxygen flow to an area of the brain.

Those most susceptible (at risk) individuals to heat stroke include:

  • Infants
  • The elderly (often with associated heart diseases, lung diseases, kidney diseases, or who are taking medications that make them vulnerable to dehydration and heat strokes)
  • Athletes
  • Individuals who work outside and physically exert themselves under the sun

Heat stroke is sometimes classified as exertional heat stroke (EHS, which is due to overexertion in hot weather) or non-exertional heat stroke (NEHS, which occurs in climactic extremes and affects the elderly, infants, and chronically ill.

Medically Reviewed by a Doctor on 5/23/2014

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Heat Stroke - Experience and Preventive Question: Describe your experience with heat stroke, and could it have been prevented?
Heat Stroke - Risk Question: If you or a relative had a heat stroke, were either of you at risk? If you are at risk, in what ways will you try to prevent an occurrence?
Heat Stroke - Treatment Question: Describe the medical treatment you received when you suffered a heat stroke.
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Avoid Heat Emergencies, Keep Hydrated

How to Recognize a Heat Related Illness

The following checklist can help you recognize the symptoms of heat-related illnesses:

  1. Heat Rash: Heat rash is a skin irritation caused by excessive sweating during hot, humid weather. It can occur at any age. Heat rash looks like a red cluster of pimples or small blisters.
  1. Heat cramps: A person who has been exercising or participating in other types of strenuous activity in the heat may develop painful muscle spasms in the arms, legs, or abdomen referred to as heat rash. The body temperature is usually normal, and the skin will feel moist and cool, but sweaty.