Neural and muscular aspects of fatigue and long-term acclimatization to high altitude.

我的研究项目包括使用创新技术来推进我们对人类神经肌肉生理学的理解，重点是疲劳的发展。体力活动产生的疲劳对健康个体来说是一种常见的体验，而且在许多人群中（例如，健康的老年人、癌症患者、心脏病患者、慢性肺病患者、中风幸存者等）会被放大，因此，即使是日常工作的表现也可能受到限制。重要的是，疲劳的发展不仅取决于任务的条件，还取决于参与者的性别和年龄等因素。我的研究计划的长期目标是确定疲劳的生理机制，并利用这些知识开发干预措施，以帮助减少疲劳对加拿大人生活的影响。本研究计划包括三个主题的实验，旨在增加我们对疲劳机制的理解。在第一个主题中，多种刺激技术（大脑的磁刺激以及脊髓和周围神经的电刺激）将在自愿收缩期间使用，以检查中枢神经系统内的疲劳机制（中枢疲劳）。有证据表明，超过50%的疲劳力损失可能是由大脑和脊髓的变化引起的，因此必须确定这些机制，并确定女性和男性之间是否存在差异。在主题二中，疲劳将通过在没有神经系统输入的情况下对肌肉施加刺激来引起收缩而引起，从而使女性和男性能够深入了解肌肉内疲劳的机制（外周疲劳）。对于运动能力有限的个体（例如中风幸存者）来说，这些电诱发的收缩是维持肌肉质量或恢复运动功能的重要手段，但会导致快速的力量损失，因此找到最佳的刺激参数以减少疲劳是很重要的。实验的最后一个主题是致力于理解氧气供应减少对疲劳的作用。为了做到这一点，居住在海平面附近的人们将前往高海拔地区，并完成自愿和电诱发协议，以评估急性缺氧暴露和适应过程中的中枢和外周疲劳。建立氧张力和疲劳之间的关系对于我们理解与血液中低氧水平相关的病理是必不可少的。

My program of research involves the use of innovative techniques to advance our understanding of human neuromuscular physiology, with emphasis on the development of fatigue. Fatigue produced by physical activity is a common experience for healthy individuals and it is magnified for many populations (e.g., healthy older adults, patients with cancer, heart disease, chronic lung disease, stroke survivors, etc.) such that the performance of even day-to-day tasks can be limited. Importantly, the development of fatigue is dependent not only on the conditions of the task but also factors such as the sex and age of the participant. It is a long-term objective of my research program to identify the physiological mechanisms of fatigue and to use this knowledge to develop interventions that will help to reduce the impact of fatigue on the lives of Canadians. This research proposal includes three themes of experiments designed to increase our understanding of the mechanisms of fatigue. In the first theme, multiple stimulation techniques (magnetic stimulation of the brain as well as electric stimulation of the spinal cord and peripheral nerve) will be used during voluntary contractions to examine mechanisms of fatigue within the central nervous system (central fatigue). There is evidence that more than 50% of force loss with fatigue can be caused by changes in the brain and spinal cord so it is imperative to identify these mechanisms and also determine if there are differences between females and males. In theme two, fatigue will be induced by applying stimulation over a muscle to cause contraction without input from the nervous system and thereby allow insight into mechanisms of fatigue within the muscle (peripheral fatigue) for females and males. These electrically-evoked contractions are an important means to maintain muscle mass or restore motor function for individuals with limited exercise capacity (e.g., a stroke survivor) but lead to rapid force loss so it is important to find the optimal stimulation parameters to minimize fatigue. The last theme of experiments is dedicated to understanding the role that reduced oxygen availability has on fatigue. To do this, people who reside close to sea level will travel to high altitude and complete voluntary and electrically-evoked protocols to assess central and peripheral fatigability with acute exposure to hypoxia and during acclimatization. Establishing the relationship between oxygen tension and fatigability is essential to our comprehension of pathologies associated with low levels of oxygen in the blood.