Hyperthermia effects on brain function and exercise capacity

Abstract

Hyperthermia has been demonstrated as an important factor limiting endurance performance in a hot environment in both human and animal studies. While temperature can affect individual peripheral physiological systems such as muscle contraction characteristics directly, a dominant role for central mechanisms for exercise impairment has been proposed over the past two decades. Exercise-induced hyperthermia may have a direct effect on the central nervous system such as brain temperature, cerebral blood flow, brain activity, cognitive function, brain neurotransmission and neuromuscular activity. In turn, these changes may affect not only the physiological capacity for exercise, but also the athlete's perception of heat stress, motivation for exercise or pacing strategy. The purpose of this review is to focus on the central mechanisms underlying human limits to exercise in heat. Specifically, the effects of hyperthermia on brain physiology and function will be summarized, along with the potential impact of these changes on regulating exercise capacity.