A dangerously overheated body, usually in response to prolonged, hot, humid weather.
Hyperthermia occurs when the body's heat-regulating mechanisms don't work effectively. Older age, certain illnesses and medications increase the risk of developing hyperthermia.
A temperature of 104 F (40 C) or higher is life-threatening. Confusion, nausea or vomiting, and rapid breathing are some symptoms.
It's critical to move a person with hyperthermia to a cooler place and seek emergency care.