Cortisol features prominently in theories describing how chronic stress wears away at physical and cognitive health. The current study examines composite measures of physiological and cognitive functioning in relation to two aspects of daily cortisol: total daily output and change in levels throughout the day. Participants (N = 1001; aged 28-84 years-old) from the Midlife Development in the United States (MIDUS) study provided 4 daily saliva samples across four consecutive days and underwent a physical exam that provided information about six inter-related physiological systems that were combined into a measure of allostatic load. They also completed a phone-based battery of cognitive tasks, which provided a composite score combining memory, reasoning, and speed of processing performance. Total daily cortisol output was captured using area under the curve with respect to ground (AUCg). Change in cortisol levels was assessed using two methods: slope, calculated through piecewise spline models, and dynamic range, calculated by the difference between the day's highest and lowest log-cortisol levels. Findings indicate that, when examined together, overall cortisol output was not associated with either outcome, but a greater range in cortisol throughout the day was associated with both lower allostatic load and higher cognitive functioning. Results emphasize the importance of dynamic daily processes, assessed either using slopes or dynamic range, to both physiological and cognitive functioning.

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走得更远：皮质醇的昼夜变化及其与认知和生理功能的关联

皮质醇在描述慢性压力如何影响身体和认知健康的理论中占有突出地位。当前的研究检查了与每日皮质醇两个方面相关的生理和认知功能的综合测量：每日总输出量和全天水平的变化。美国中年发展 (MIDUS) 研究的参与者（N = 1001；年龄 28-84 岁）连续四天每天提供 4 份唾液样本，并接受体检，提供有关六个相互关联的生理系统的信息这些被组合成一个静态负荷的量度。他们还完成了一系列基于手机的认知任务，这些任务提供了综合记忆力、推理能力和处理速度的综合得分。使用相对于地面的曲线下面积 (AUCg) 捕获每日总皮质醇输出。使用两种方法评估皮质醇水平的变化：斜率，通过分段样条模型计算，以及动态范围，通过当天最高和最低对数皮质醇水平之间的差异计算。结果表明，当一起检查时，总体皮质醇输出与任一结果均无关，但全天皮质醇的较大范围与较低的稳态负荷和较高的认知功能相关。结果强调了使用斜率或动态范围评估的动态日常过程对生理和认知功能的重要性。通过分段样条模型和动态范围计算，通过当天最高和最低对数皮质醇水平之间的差异计算。结果表明，当一起检查时，总体皮质醇输出与任一结果均无关，但全天皮质醇的较大范围与较低的稳态负荷和较高的认知功能相关。结果强调了使用斜率或动态范围评估的动态日常过程对生理和认知功能的重要性。通过分段样条模型和动态范围计算，通过当天最高和最低对数皮质醇水平之间的差异计算。结果表明，当一起检查时，总体皮质醇输出与任一结果均无关，但全天皮质醇的较大范围与较低的稳态负荷和较高的认知功能相关。结果强调了使用斜率或动态范围评估的动态日常过程对生理和认知功能的重要性。但全天较大范围的皮质醇与较低的平衡负荷和较高的认知功能有关。结果强调了使用斜率或动态范围评估的动态日常过程对生理和认知功能的重要性。但全天较大范围的皮质醇与较低的平衡负荷和较高的认知功能有关。结果强调了使用斜率或动态范围评估的动态日常过程对生理和认知功能的重要性。