Do regulated differences in resting body temperature or thermal behaviour affect heat tolerance, cerebrovascular or respiratory control during exercise heat stress

作者：Tiarna Stothers · 发表于：Otago University Research Archive (University of Otago) · 年份：2022 · 研究领域：Thermoregulation and physiological responses、Thermal Regulation in Medicine、Infrared Thermography in Medicine

Background: Maintaining appropriate brain blood flow is vital to supplying oxygen and energy substrates, and removing metabolic by-products (carbon dioxide and heat). However, high body temperature results in hyperventilation, which lowers blood carbon dioxide levels thereby constricting cerebral blood vessels and reducing flow. This exacerbates brain temperature as metabolism (thus heat production) continues at the same rate. High core (especially brain) temperature is considered the main cause of heat tolerance. Accordingly, initial core temperature is known to influence heat tolerance. Core temperature increases by ~0.5 °C across the day and the menstrual cycle but whether these regulated variations affect heat tolerance, cerebrovascular or respiratory control in uncompensable exercise heat stress remains unknown. Furthermore, research into exercise heat tolerance typically excludes the opportunity for behavioural thermoregulation, which is the most effective means of controlling core temperature. Behavioural thermoregulation is driven by thermal discomfort, which may be a key confounding factor (e.g., affect hyperventilation or motivation). Therefore, the mechanisms that drive heat tolerance remain unknown; leading us to question the effect behavioural thermoregulation has on heat tolerance. Aim: To assess (i) how diurnal changes in core temperature affect heat tolerance, cerebrovascular and respiratory control; (ii) what mechanisms (physiological, psychological or both) ...