Abstract Introduction:

Despite sparse systematic evidence, current exercise heat safety recommendations suggest that antihistamines blunt sweating and increase the risk for heat-related injury during exertional heat stress. The primary purpose of the present study was to examine whether diphenhydramine hydrochloride (DPH), a first-generation antihistamine, effects the sweating, core temperature, and heart rate response during exertional heat stress using a double-blind randomized crossover design.

Abstract Conclusions:

50 mg of DPH does not modify the sweating, core temperature, and heart rate response during exertional heat stress in young healthy adults.