Medical Term Definition

Heatstroke

Heatstroke is a life-threatening medical emergency in which the body becomes dangerously overheated and its ability to regulate temperature fails, often accompanied by changes in brain function.

Heatstroke can occur after strenuous physical activity in hot conditions, known as exertional heatstroke, or after prolonged exposure to high environmental temperatures, known as classic or non-exertional heatstroke. High humidity, dehydration, certain medications, underlying health conditions, and limited access to cooling can increase the risk.

Warning signs may include confusion, unusual behavior, difficulty walking, seizures, collapse, or loss of consciousness. The skin may be hot and dry, but a person with heatstroke can still be sweating, particularly when the condition follows strenuous exercise. Therefore, sweating does not rule out heatstroke.

Suspected heatstroke requires immediate emergency medical assistance. Begin rapid cooling while help is on the way. Move the person away from heat, remove unnecessary outer clothing, and cool the body using cold water, wet towels, fans, or other available methods. Cold-water immersion can be particularly effective for exertional heatstroke when it can be performed safely. Follow emergency-dispatch instructions and do not delay cooling while waiting for transport.

Do not give anything by mouth to a person who is confused, having a seizure, unconscious, or unable to swallow safely.

QUICK FACT

A dangerously overheated person does not need to have completely dry skin to have heatstroke. Altered mental status after heat exposure or exertion is a major warning sign.

COMMONLY CONFUSED WITH

  • Heat exhaustion: A less severe heat-related illness that may cause heavy sweating, weakness, dizziness, and nausea without the severe brain dysfunction associated with heatstroke.
  • Fever: An increase in the body’s temperature set point, usually in response to infection or inflammation. Heatstroke results from the body’s inability to manage excessive heat, rather than the same temperature-regulating process that causes fever.
  • Seizure: An episode of abnormal electrical activity in the brain. A seizure can occur during heatstroke, but the two terms describe different conditions.

SEE ALSO