The Potential Role of Exercise-Induced Muscle Damage in Exertional Heat Stroke

Exertional heat stroke (EHS) is a life-threatening condition that affects mainly athletes, military personnel, firefighters, and occupational workers. EHS is frequently observed in non-compensable conditions (where the body is unable to maintain a steady thermal balance) as a result of heavy heat stress and muscle contraction associated with prolonged and strenuous physical and occupational activities, resulting in central nervous system dysfunction followed by multi-organ damage and failure. Since the pathophysiology of EHS is complex and involves multiple organs and systems, any condition that changes the interrelated systems may increase the risk for EHS. It has been suggested that exercise-induced muscle damage (EIMD) can lead to thermoregulatory impairment and systemic inflammation, which could be a potential predisposing factor for EHS. In this review article, we aim to (1) address the evidence of EIMD as a predisposing factor for EHS and (2) propose a possible mechanism of how performing muscle-damaging exercise in the heat may aggravate muscle damage and subsequent risk of EHS and acute kidney injury (AKI). Such an understanding could be meaningful to minimize the risks of EHS and AKI for individuals with muscle damage due to engaging in physical work in hot environments.