Hyperthermia is an increase in body temperature above normal (above 37.5–38°C) that occurs as a response to infection, inflammation, tumors, or other pathologies. It can be a short-term physiological condition or a symptom of a serious illness.
Within moderate limits, hyperthermia performs a protective function by activating the immune response. However, at excessively high values (above 39–40 °C), it can be dangerous and requires medical intervention to lower the temperature and eliminate the cause.