Heat stroke: A core body temperature that rises above 104 F (40 C) accompanied by hot, dry skin and central nervous system abnormalities such as delirium, convulsions, or coma. Heat stroke that results from exposure to a high environmental temperature is called nonexertional heat stroke. Heat stroke that results from strenuous exercise is called exertional heat stroke. Irrespective of type, heat stroke can be life-threatening. Immediate medical attention is essential when problems first begin. Symptoms may include confusion, combativeness, bizarre behavior, faintness, staggering, strong rapid pulse, dry flushed skin, lack of sweating, possible delirium or coma.