Thermal influences governing oxygen delivery and extraction on skeletal muscle metabolism during exercise

人体暴露在冷热环境中会影响骨骼肌氧输送和线粒体氧化磷酸化(OXPHOS)能力。冷或热暴露对骨骼肌的氧气输送和线粒体中氧气提取的波动控制着能量代谢的调节机制。能量代谢是多因素的，并受运动和环境的调节。虽然人们知道在寒冷和炎热环境中运动会分别增加脂肪和碳水化合物的氧化，但仍然存在两个问题：1)运动和环境代谢已被初步独立研究，但对两者的联合影响的认识有限；2)在运动研究中，寒冷和高温对氧气利用和提取的影响尚未得到全面评估，并随后与能量代谢有关。运动过程中骨骼肌氧输送和线粒体氧摄取的变化及其对骨骼肌能量代谢代谢变化的影响尚不清楚。我的研究项目旨在研究在寒冷和炎热的运动中，控制氧气输送和提取的热影响，并随后确定它们在调节骨骼肌代谢中的作用。在接下来的几年里，将开展一系列研究，通过空间分辨光谱技术研究骨骼肌组织的氧合和氧摄取，通过高分辨率呼吸测量研究体外线粒体的氧合能力，以及在寒冷和高温下运动时肌肉活检的全身和肌肉内能量底物的利用。我的计划的第一阶段将包括专门针对寒冷和炎热环境下运动期间氧气输送和提取的波动的研究。第二阶段将根据第一阶段的研究结果，重点研究能量代谢的调节机制。这项研究计划旨在提高我们对人体生物系统的了解，更准确地说，是我们对肌肉热和氧化生理以及热应激下的能量代谢的理解。除了这一范围之外，我们还旨在为普通民众实施信息丰富的基于环境的运动指南，并为必须在寒冷或温暖条件下执行体力任务、有时是关键任务的职业工人/军事人员/户外运动运动员制定安全工作指南和协议。这项工作的成果将进一步作为工业和技术发展的基准，以限制寒冷和炎热对地下矿工、消防员、食品加工工人、建筑工人和其他职业群体的不利影响。

Human exposure to cold and hot environments influences oxygen (O2) delivery to skeletal muscles and mitochondrial oxidative phosphorylation (OXPHOS) capacity. Fluctuations in O2 delivery to skeletal muscles and O2 extraction in the mitochondria from cold or heat exposure govern mechanisms regulating energy metabolism. Energy metabolism is multi-factorial and modulated by exercise and the environment. While it is known that exercise in a cold and hot environment increases lipids carbohydrates oxidation, respectively, two problems remain: 1) exercise and environmental metabolism have been primarily studied independently with limited insights on combined influences, and 2) the effects of cold and heat on O2 availability and extraction has yet to be comprehensively evaluated during exercise studies, and subsequently linked to energy metabolism. The combined influence of altered O2 delivery to skeletal muscles and O2 extraction in mitochondria and their influence on the metabolic shift in skeletal muscle energy metabolism in extreme environments during exercise is unclear. My research program aims at examining the thermal influences governing O2 delivery and extraction during exercise in the cold and heat, and subsequently determine their roles in regulating skeletal muscle metabolism. Over the next years, a series of studies will be conducted to investigate skeletal muscle tissue oxygenation and oxygen uptake via spatially-resolved spectroscopy technology, in vitro mitochondrial OXPHOS capacity via high resolution respirometry, as well as systemic and intra-muscular energy substrate utilization from muscle biopsies during exercise in the cold and heat. Phase I of my program will included studies specifically targeting fluctuations in O2 delivery and extraction studies during exercise in cold and hot environment. Phase II will focus on studies examining energy metabolism regulating mechanisms based on results of Phase I. This research program is designed to improve our knowledge of human biological systems, more precisely, our understanding of muscle thermal and oxidative physiology and energy metabolism under thermal stress. Beyond this scope, we also aim to implement informative environmentally-based exercise guidelines for the general population in addition to develop safety working guidelines and protocols for occupational workers/military personnel/outdoor sports athletes having to perform physical, sometimes critical tasks under cold or warm conditions. The results stemming from this work will further be used as a benchmark in industrial and technological development to limit the detrimental influences of cold and heat for underground miners, firefighters, food processing workers, construction workers, and other occupational groups.