The Air Calorimeter: an innovative tool for the scientific discovery of the human heat stress response in a warming planet

温度调节是人类生存的一个重要方面，因为体内温度的相对较小的偏差可能导致全身热平衡的严重破坏。这种平衡在暴露于炎热环境和/或由于运动而增加的代谢产热时很容易被破坏。为了抵消这种增加，高度发达的自主热调节反应被激活，以增加全身热损失。位于渥太华大学的Snellen空气量热计是世界上唯一能够测量这种高度动态和强大的生理反应的主动量热计。这种独特的科学工具提供了人体散热和储存热量的精确测量，从而使人类热应激反应的前沿研究成为可能。如果没有全身量热仪的好处，我们测量全身热交换的能力只能通过测量皮肤血流和出汗的局部热损失反应（全身热损失的替代测量）和/或体温（身体热储存的替代测量）来估计。正如我们的研究所表明的那样，这可能会导致关于特定热应激下个人热应变水平的错误结论。在此申请中，我们要求更换一些即将永久失效的老化仪器。我们将用更新的、最先进的组件替换它们，这些组件具有更高的操作响应性和/或测量灵敏度，这将改善我们对全身热交换和身体热量储存的热量测量。这些包括i)用于测量干热交换和质量流量的高精度温度传感器的记录系统，ii)用于测量热量产生并用于量化身体热量储存的气体分析仪，以及iii)用于调节运动期间热量产生的涡流测功仪。为了提高我们的热量计的操作能力，我们试图在热量计地板上安装一个称重传感器平台，这将允许连续测量汗水损失，同时测量全身蒸发热损失，这将使我们具有无与伦比的测量全身出汗效率的能力。提高我们的量热计运行能力的关键是重新配置控制量热计所有机械部件（加热器、锅炉等）和仪器（测力计、气体分析仪、生理装置等）的软件平台。本应用程序中要求的组件将确保量热计保持功能，以实现人体体温调节的基础研究，从而在我们对人体热应激反应的理解方面有新的发现。重要的是，它将吸引一批新的培训骨干，推动新一代的科学发展和文化，以应对工业和其他受地球变暖引发的极端高温影响的人群所面临的现实挑战。

Temperature regulation is a vital aspect of human survival as relatively small deviations in internal body temperature can lead to profound disruptions in whole-body heat balance. This balance is easily disturbed during exposure to a hot environment and/or increases in metabolic heat production due to exercise. To offset this increase, highly developed autonomic thermoregulatory responses are activated to enhance whole-body heat loss. The Snellen air calorimeter housed at the University of Ottawa is the world's only active calorimeter capable of measuring this highly dynamic and powerful physiologic response. This unique scientific tool provides an accurate measure of the heat dissipated and stored by the body, thereby enabling leading-edge research on the human heat stress response. Without the benefit of whole-body calorimetry our ability to measure whole-body heat exchange can only be estimated by the measurement of local heat loss responses of skin blood flow and sweating (surrogate measures of whole-body heat loss) and/or body temperatures (proxy measure of body heat storage). As our research demonstrates, this can lead to misguided conclusions about an individual's level of thermal strain to a given heat stress. In this application, we are requesting the replacement of some aging instruments in imminent danger of failing permanently. We will replace these with newer, state-of-art components with greater operational responsiveness and/or measurement sensitivity that will improve our calorimetric measurement of whole-body heat exchange and body heat storage. These include i) recording system for the high-precision temperature sensors critical to the measurement of dry heat exchange and mass flow, ii) gas analysers to measure heat production and used to quantify body heat storage, and iii) Eddy current ergometer to regulate heat production during exercise. To enhance the operational capacity of our calorimeter we seek to install a load cell platform on the calorimeter floor that will permit the continuous measurement of sweat loss that with the concomitant measurement of whole-body evaporative heat loss will give us an unparalleled ability to measure whole-body sweating efficiency. Key to the improvement of the operational capability of our calorimeter will be the reconfiguration of the software platform that controls all mechanical components (heater, boiler, other) and instruments (ergometer, gas analyzers, physiological devices, other) of the calorimeter. The components requested in this application will ensure that the calorimeter remains functional to enable fundamental research in human thermoregulation leading to new discoveries in our understanding of the human heat stress response. Importantly, it will attract a new cadre of trainees and drive a new generation and culture of scientific growth to address real-world challenges faced by industry and other sectors of our population affected by extreme heat spurred by a warming planet.