Hyperthermia, also known as overheating, is a condition in which an individual's body temperature is elevated beyond normal due to failed thermoregulation. The person's body produces or absorbs more heat than it dissipates.

Heat stroke and heat exhaustion involve an abnormally high body temperature (hyperthermia) and need immediate treatment. You can lower your risk of heat illness by staying hydrated and limiting physical activity in hot weather.

Hyperthermia, or heat-related illness, occurs when the body’s heat-regulation system becomes overwhelmed by outside factors, causing a person’s internal temperature to rise.

Preventive care Heat stroke (hyperthermia) March 13, 2026 Reviewed by Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing Share Print This Page

Hyperthermia occurs when your temperature climbs too high and threatens your health. Here's why this happens and what you can do to prevent illness.

Hyperthermia therapy (or hyperthermia, or thermotherapy) is a type of medical treatment in which body tissue is exposed to temperatures above body temperature, in the region of 40–45 °C (104–113 °F).

Hyperthermia is defined as a condition in which thermoregulatory mechanisms are overwhelmed by excessive heat production, heat storage, or dysfunctional heat dissipation, without a resetting of the temperature set point.

Find out about heat exhaustion and heatstroke, which can happen if you get too hot during hot weather.

Learn what hyperthermia is, how it differs from fever, symptoms, diagnosis, treatment, cancer therapy applications, and prevention tips for all age groups.

VA/VV-ECMO: consider in refractory circulatory failure/hypoxia with hyperthermia (severe heat stroke with ongoing collapse) for perfusion support and controlled heat exchange; requires experienced ECMO resources.