Heat Stress Responses to Exercise: related mechanisms and biomarkers
حوزههای تخصصی:
The pathophysiology of heat stress occurs when the body's environmental and physiological responses exceed its ability to maintain homeostasis. When internal heat signals or external factors raise body temperature beyond a certain limit that the cooling mechanisms can effectively manage, the resulting increase in core temperature triggers response pathways that themselves induce physiological stress. The primary response mechanisms to heat stress include sweating, peripheral vasodilation, and shivering as thermogenic responses—all of which are activated by elevated temperatures and may seem counterproductive to the body's requirements, yet they operate through a neuromuscular and hormonal feedback system. Genetic factors influence individual heat tolerance; for instance, certain populations have variations in heat shock proteins (HSP70) and ion channels (TRPV1, RYR1) that enhance their heat response and tolerance. Additionally, individuals with higher relative VO2 max levels demonstrate greater heat tolerance, as those who are physically trained exhibit more sudomotor activity and effective evaporative cooling compared to untrained individuals. Furthermore, individuals who acclimatize to heat over time develop improved thresholds for heat stress, enabling them to better regulate internal and cardiovascular temperature stresses during exposure. This knowledge is crucial for populations at risk and in situations where physical exertion is required in hot conditions.