Table Some Differences Between Classic and Exertional Heatstroke Characteristic Classic Heatstroke Exertional Heatstroke Onset 2 - 3 days Hours Patients usually affected Older, sedentary people Healthy active people (eg, athletes, military recruits, factory workers) Risk factors No air-conditioning during summer heat waves Intense exertion, particularly without acclimatization Skin Usually hot and dry but sometimes moist with sweat Often moist with sweat Heatstroke may occur after using stimulant drugs (eg, cocaine, phencyclidine [PCP], amphetamines), monoamine oxidase inhibitors, or anticholinergic medications (eg, antihistamines, antimuscarinics) that cause a hypermetabolic state or impair the ability to sweat.