Understanding the physiological factors affecting human heat dissipation

温度调节是人类生存的一个重要方面，因为体内(即核心)温度相对较小的偏差可能会导致全身动态平衡的严重破坏。长时间暴露在炎热的环境中和/或进行剧烈运动会使身体变热，导致体内体温显著上升。这种热量通过接触冷空气和汗液产生而失去，汗液蒸发时会使你的身体降温。然而，当身体不能通过出汗来降温时，可能会发生几种由热引起的疾病，如热应激或热衰竭，以及更严重的中暑，并可能导致死亡。我们的工作表明，存在许多非温度因素(感觉器官：代谢性感受器、压力感受器等)和内在因素：性别、衰老、水合状态、健康等。这会对身体散热的生理能力产生深远的影响。我们的工作旨在了解这些因素在与环境(环境温度升高)和/或代谢(运动)热负荷逐渐升高相关的挑战期间对人体热平衡的单独和相对贡献。为了更深入地了解非热因素可能会导致身体生理能力的变化，我们正在使用世界上唯一的全身热量计(一种测量身体发出的热量的设备)来测量身体正在释放的热量。通过了解环境热负荷和代谢热负荷的精确组合，我们可以开始更好地理解热应激是如何发展的。作为这笔赠款的一部分，获得的资金将用于购买研究仪器，这些仪器将有助于维持世界上唯一的热量计(露点镜：用于调节环境湿度和测量全身出汗反应)的运行，并增加研究能力(激光多普勒血流仪：用于测量皮肤血液流动，从而测量局部热量损失)。

Temperature regulation is a vital aspect of human survival as relatively small deviations in internal body (i.e. core) temperature can lead to profound disruptions in whole-body homeostasis. Prolonged exposure to hot environments and/or performing strenuous exercise can heat the body causing significant increases in internal body temperature. This heat is lost by contact with cool air and by sweat production, which cools your body as the sweat evaporates. However, when the body is unable to cool itself by sweating, several heat-induced illnesses such as heat stress or heat exhaustion and the more severe heat stroke can occur, and can result in death. Our work has demonstrated that there are a number of nonthermal factors (sensory end organs: metaboreceptors, baroreceptors, etc. and intrinsic factors: sex, aging, hydration status, fitness, etc.) that can have profound effects on the body's physiological capacity to dissipate heat. Our work is directed at understanding the separate and relative contribution of these factors during challenges to human heat balance associated with progressive elevations in environmental (elevated ambient temperature) and/or metabolic (exercise) heat load. To achieve an advanced understanding of the changes that nonthermal factors may elicit in the body's physiological capacity to dissipate, we are using the world's only whole-body calorimeter (a device for measuring heat emitted by the body) to measure how much heat the body is loosing. By understanding the precise combination of environmental and metabolic heat loads where physiological differences in the body's capacity to dissipate heat occur, we can begin to develop a better understanding of how heat stress develops. Funds obtained as part of this grant will be used to purchase research instruments that will help to maintain the operation of the world's only calorimeter (dew point mirror: used to regulate ambient humidity and measure whole-body sweating response) and increase capacity for research (laser-Doppler flowmetry: used to measure skin blood flow and therefore local heat loss).