What is the medical term for a significant increase in body temperature?

The term describing a significant increase in body temperature is "hyperthermia." This condition occurs when the body's temperature regulation fails and the body temperature rises to dangerous levels, often as a result of prolonged exposure to high temperatures or excessive physical activity in hot conditions.

Hyperthermia differs from "fever," which is a specific type of increased body temperature often associated with illness or infection; it usually indicates the body's immune response. "Hypothermia" refers to dangerously low body temperature, and "chill" is a sensation of cold or shivering, which does not directly relate to an increase in body temperature. Understanding these distinctions is essential in the medical field to properly identify and respond to different thermal states in patients.