Mechanisms of Cross-tolerance between Heat and Hypoxia Acclimation

我们提出的研究的目标是了解人类如何同时对高温和模拟海拔的组合做出反应。到目前为止，很少有研究关注这个问题。大多数研究一次只关注一种环境条件。然而，最近的一些研究表明，暴露在高温和高原环境中可能会产生协同作用。具体地说，如果一个人习惯了高温，他们似乎在模拟海拔中表现得更好。在海拔高的地方，周围空气中的氧气水平低(这叫缺氧)，对身体造成很大的压力，导致表现不佳，思考和学习能力差，有时甚至生病。*如果热适应和低氧适应之间存在相互作用，就有可能使人们做好准备，更好地适应这些恶劣的条件。*本研究的目的是深入研究这种相互作用。确认其存在和程度的第一步。其次，我们的目标是试图理解导致这种相互作用的机制。人类对高温和低氧有共同的反应机制吗？热适应能用来改善低氧适应吗？似乎如果存在交互作用，它可能与运动成绩有关，因为如果人们习惯了高热，他们在高温下的运动表现会更好。我们怀疑他们在高原(或模拟海拔)的运动表现也可能会变得更好。在这些条件下提高运动成绩对所有在户外工作和娱乐的人都很重要，从临时锻炼者到运动员，再到军人，再到在炎热高温环境中工作的工人。*有趣的是，最近有一些证据表明，这种热适应也可能改善认知能力。我们还打算调查高温和低氧对认知的影响，以确定这里是否真的存在交互作用。我们将通过观察认知健康的血液标记物，以及通过执行一系列认知任务来测试认知能力。*参与者将多次访问实验室，参与高温、缺氧和假(安慰剂)暴露，以适应高温，并测试他们对缺氧的反应。

The goal of our proposed research is to understand how human beings respond to a combination of heat and simulated altitude at the same time. To date, very little research has looked at this question. Most research has focussed on one environmental condition at a time. However, there is some recent research that indicates that exposure to heat and exposure to altitude might act synergistically. Specifically, if one becomes acclimated to heat, it appears they do better in simulated altitude. At altitude, the oxygen level in the surrounding air is low (this is called hypoxia), and it is very stressful on the body, leading to poor performance, poor ability to think and learn, and sometimes even illness. ***If there is an interaction between heat acclimation and hypoxia acclimation, it could have the potential to prepare people to better adapt to these harsh conditions. ******The goal of this research is to thoroughly investigate this interaction. The first step to confirm its existence and its extent. Secondly, we aim to try to understand the mechanisms responsible for this interaction. Are there common mechanisms by which humans react to heat and to hypoxia? Can heat acclimation can be used to improve hypoxia acclimation? ******It seems that if there is an interaction it might relate to exercise performance, in that if people become acclimated to high heat, their exercise performance in the heat gets better. We suspect that their exercise performance at altitude (or simulated altitude) might also get better. Improving exercise performance under these conditions is important for all people that work and play in the outdoors, from casual exercisers, to athletes, to military personnel, to workers that work in hot, high environments. ******Interestingly, there is some recent evidence that this heat acclimation might also improve cognition. We also aim to investigate the effects of heat and hypoxia on cognition, to determine if there truly is an interaction here. We will test cognition by looking both at blood markers of cognitive health, but also by performing a battery of cognitive tasks.******Participants will visit the lab on multiple occasions partaking in heat, hypoxia and sham (placebo) exposures to acclimate them to heat, and to test their response to the hypoxia.