Heat illnesses exist along a continuum starting with the mild condition of heat exhaustion and progressing to heat injury and heat stroke. Heat stroke is a life-threatening condition clinically characterized by a severe elevation in body temperature with central nervous system dysfunction that often includes combativeness, delirium, seizures, and coma. Classic heat stroke is experienced primarily by the very young or elderly during annual heat waves. Exertional heat stroke is a condition experienced by young, fit individuals during strenuous physical activity in hot or temperate environments....