Exercise and Immune Function
Exercise and Immune Function
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运动与免疫功能
作者：
D. Nieman;B. Pedersen
比较运动员和非运动员的免疫功能表明，适应性免疫系统在很大程度上不受运动努力的影响。先天免疫系统似乎对高强度运动的慢性应激反应不同，自然杀伤细胞活性趋于增强，而中性粒细胞功能受到抑制。然而，即使在运动员中观察到免疫参数水平和功能活性的显著变化，研究人员也很少成功地将这些与感染和疾病的高发病率联系起来。在这种免疫力改变的“开放窗口”期间（可能持续3至72小时，取决于测量的参数），病毒和细菌可能会站稳脚跟，增加亚临床和临床感染的风险。然而，研究人员并没有认真尝试证明，运动后表现出最极端免疫抑制的运动员是那些在随后的1至2周内感染的运动员。这种联系必须在“开放窗口”理论被完全接受之前建立起来。营养补充剂，主要是锌、维生素C、谷氨酰胺和碳水化合物，对耐力运动员对长时间运动的急性免疫反应的影响已经在耐力运动员中进行了测量。维生素C和谷氨酰胺受到了很多关注，但迄今为止的数据还不确定。最令人印象深刻的结果是在碳水化合物补充研究中报道的。碳水化合物饮料摄入与较高的血糖水平、减弱的皮质醇和生长激素反应、较少的血液免疫细胞计数扰动、较低的粒细胞和单核细胞吞噬作用和氧化爆发活性以及减少的促炎和抗炎细胞因子反应相关。补充碳水化合物是否能减少剧烈运动后恢复期的感染频率还有待证实。关于适度运动训练对宿主保护和免疫功能影响的研究表明，在12至15周的时间内，与不运动相比，几乎每天快走可将患病天数减少一半，而静息免疫功能无变化。适度运动训练对免疫监视和宿主保护的积极影响可能与每次运动期间发生的急性积极变化的总和效应有关。目前还没有令人信服的数据表明，适度的运动训练与艾滋病患者辅助性T细胞计数的改善或老年参与者免疫力的增强有关。
Comparison of immune function in athletes and nonathletes reveals that the adaptive immune system is largely unaffected by athletic endeavour. The innate immune system appears to respond differentially to the chronic stress of intensive exercise, with natural killer cell activity tending to be enhanced while neutrophil function is suppressed. However, even when significant changes in the level and functional activity of immune parameters have been observed in athletes, investigators have had little success in linking these to a higher incidence of infection and illness.Many components of the immune system exhibit change after prolonged heavy exertion. During this ‘open window’ of altered immunity (which may last between 3 and 72 hours, depending on the parameter measured), viruses and bacteria may gain a foothold, increasing the risk of subclinical and clinical infection. However, no serious attempt has been made by investigators to demonstrate that athletes showing the most extreme post-exercise immunosuppression are those that contract an infection during the ensuing 1 to 2 weeks. This link must be established before the ‘open window’ theory can be wholly accepted.The influence of nutritional supplements, primarily zinc, vitamin C, glutamine and carbohydrate, on the acute immune response to prolonged exercise has been measured in endurance athletes. Vitamin C and glutamine have received much attention, but the data thus far are inconclusive. The most impressive results have been reported in the carbohydrate supplementation studies. Carbohydrate beverage ingestion has been associated with higher plasma glucose levels, an attenuated cortisol and growth hormone response, fewer perturbations in blood immune cell counts, lower granulocyte and monocyte phagocytosis and oxidative burst activity, and a diminished pro- and anti-inflammatory cytokine response. It remains to be shown whether carbohydrate supplementation diminishes the frequency of infections in the recovery period after strenuous exercise.Studies on the influence of moderate exercise training on host protection and immune function have shown that near-daily brisk walking compared with inactivity reduced the number of sickness days by half over a 12- to 15-week period without change in resting immune function. Positive effects on immunosurveillance and host protection that come with moderate exercise training are probably related to a summation effect from acute positive changes that occur during each exercise bout. No convincing data exist that moderate exercise training is linked with improved T helper cell counts in patients with HIV, or enhanced immunity in elderly participants.