Heat stroke is a medical emergency, and the most severe form of heat related illness. Anyone exhibiting the signs and symptoms of heat stroke should be rushed to the nearest hospital or clinic. Unlike other forms of heat illness, heat stroke does not have to be caused by exercise or exertion. High temperatures, lack of body fluids and overexposure to the elements can all bring about heat stroke. The very young and old are especially susceptible to the hazards of this heat related illness.