Departments of Nutritional Sciences, Pediatrics and Immunobiology, University of Arizona, Tucson, AZ, USA.
Department for Health, University of Bath, Claverton Down, Bath, BA2 7AY. UK.
Exerc Immunol Rev. 2020;26:8-22.
Multiple studies in humans and animals have demonstrated the profound impact that exercise can have on the immune system. There is a general consensus that regular bouts of short-lasting (i.e. up to 45 minutes) moderate intensity exercise is beneficial for host immune defense, particularly in older adults and people with chronic diseases. In contrast, infection burden is reported to be high among high performance athletes and second only to injury for the number of training days lost during preparation for major sporting events. This has shaped the common view that arduous exercise (i.e. those activities practiced by high performance athletes/ military personnel that greatly exceed recommended physical activity guidelines) can suppress immunity and increase infection risk. However, the idea that exercise per se can suppress immunity and increase infection risk independently of the many other factors (e.g. anxiety, sleep disruption, travel, exposure, nutritional deficits, environmental extremes, etc.) experienced by these populations has recently been challenged. The purpose of this debate article was to solicit opposing arguments centered around this fundamental question in the exercise immunology field: can exercise affect immune function to increase susceptibility to infection. Issues that were contested between the debating groups include: (i) whether or not athletes are more susceptible to infection (mainly of the upper respiratory tract) than the general population; (ii) whether exercise per se is capable of altering immunity to increase infection risk independently of the multiple factors that activate shared immune pathways and are unique to the study populations involved; (iii) the usefulness of certain biomarkers and the interpretation of in vitro and in vivo data to monitor immune health in those who perform arduous exercise; and (iv) the quality of scientific evidence that has been used to substantiate claims for and against the potential negative effects of arduous exercise on immunity and infection risk. A key point of agreement between the groups is that infection susceptibility has a multifactorial underpinning. An issue that remains to be resolved is whether exercise per se is a causative factor of increased infection risk in athletes. This article should provide impetus for more empirical research to unravel the complex questions that surround this contentious issue in the field of exercise immunology.
多项人类和动物研究表明，运动对免疫系统有深远影响。人们普遍认为，定期进行短暂（即不超过 45 分钟）的中等强度运动对宿主的免疫防御有益，尤其是在老年人和患有慢性病的人群中。相比之下，高强度运动员的感染负担较高，仅次于伤病，在为重大体育赛事做准备期间，因伤病而错过的训练天数仅次于感染。这就形成了一种普遍观点，即剧烈运动（即高强度运动员/军人所进行的大大超出推荐体力活动指南的活动）会抑制免疫力并增加感染风险。然而，运动本身会独立于这些人群所经历的许多其他因素（例如焦虑、睡眠中断、旅行、暴露、营养不足、极端环境等）抑制免疫力并增加感染风险的观点最近受到了挑战。本文的目的是围绕运动免疫学领域的这个基本问题，即运动是否会影响免疫功能从而增加感染易感性，征求对立的观点。辩论双方争议的问题包括：（i）运动员是否比一般人群更容易感染（主要是上呼吸道）；（ii）运动本身是否能够改变免疫力从而增加感染风险，而不考虑激活共享免疫途径的多种因素，这些因素是研究人群所特有的；（iii）在那些进行剧烈运动的人群中，监测免疫健康的某些生物标志物的有用性以及体外和体内数据的解释；（iv）用于支持和反对剧烈运动对免疫和感染风险的潜在负面影响的科学证据的质量。双方的一个主要共识是，感染易感性具有多因素的基础。仍有待解决的问题是，运动本身是否是运动员感染风险增加的一个原因。本文应为解开运动免疫学领域这一有争议问题背后的复杂问题提供更多的实证研究动力。
