BACKGROUND Prolonged activation of the hypothalamus-pituitary-adrenal system is thought to have deleterious effects on brain function. Neuroendocrine studies suggest that brain exposure to higher cortisol concentrations contribute to cognitive deficits as we age. Mind-body techniques such as yoga have shown to improve stress levels by restoring the body's sympathetic-parasympathetic balance. The objective of this study was to determine whether yoga practice moderated the stress response resulting in improved executive function. METHODS Sedentary community dwelling older adults (N=118, Mean age=62.02) were randomized to an 8-week yoga intervention or a stretching control group. At baseline and following 8 weeks, all participants completed measures of executive function, self-reported stress and anxiety and provided saliva samples before and after cognitive testing to assess cortisol. RESULTS Yoga participants showed improved accuracy on executive function measures and an attenuated cortisol response compared to their stretching counterparts who showed increased cortisol levels and poor cognitive performance at follow up. The change in cortisol levels as well as self-reported stress and anxiety levels predicted performance on the running span task, n-back working memory and task switching paradigm (β's=0.27-0.38, p's≤0.05 for yoga and β's=-0.37-0.47, p's≤0.01 for stretching control). CONCLUSION Eight weeks of regular yoga practice resulted in improved working memory performance that was mediated by an attenuated response to stress as measured by self-report stress and objective salivary cortisol measurements. This trial offers evidence for non-traditional physical activity interventions such as yoga that may be helpful in restoring HPA balance in older adults, thereby preventing cognitive decline.

中文翻译：

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瑜伽练习通过减轻压力水平来改善执行功能

背景下丘脑-垂体-肾上腺系统的长期激活被认为对脑功能具有有害影响。神经内分泌研究表明，随着年龄的增长，大脑暴露于更高浓度的皮质醇会导致认知缺陷。瑜伽等身心技术已被证明可以通过恢复身体的交感神经-副交感神经平衡来改善压力水平。本研究的目的是确定瑜伽练习是否能减轻压力反应，从而改善执行功能。方法 久坐社区居住的老年人（N = 118，平均年龄 = 62.02）被随机分配到 8 周瑜伽干预组或拉伸对照组。在基线和 8 周后，所有参与者完成了执行功能的测量，自我报告的压力和焦虑，并在认知测试之前和之后提供唾液样本以评估皮质醇。结果 与在随访时表现出皮质醇水平升高和认知能力差的伸展运动参与者相比，瑜伽参与者表现出执行功能测量的准确性提高和皮质醇反应减弱。皮质醇水平的变化以及自我报告的压力和焦虑水平预测了跑步跨度任务、n-back 工作记忆和任务转换范式的表现（β's=0.27-0.38，瑜伽 p's≤0.05，β's=-0.37- 0.47, p's≤0.01 用于拉伸控制）。结论 八周的常规瑜伽练习可改善工作记忆表现，这是通过自我报告压力和客观唾液皮质醇测量来衡量的对压力的减弱反应介导的。该试验为瑜伽等非传统体育活动干预措施提供了证据，这些干预措施可能有助于恢复老年人的 HPA 平衡，从而防止认知能力下降。