Wetherell Mark A, Lovell Brian, Smith Michael A
Stress Research Group, Department of Psychology, University of Northumbria , Newcastle upon Tyne , UK.
Stress. 2015 Jan;18(1):42-8. doi: 10.3109/10253890.2014.993967. Epub 2014 Dec 29.
In healthy, non-challenged individuals, the secretion of cortisol typically follows a diurnal profile characterized by a peak in the period following waking (cortisol awakening response) and a gradual decline throughout the day. In addition, cortisol secretion is increased in response to acutely stressful stimuli, particularly stressors involving social evaluation. The current study is the first to assess the impact of an anticipated acute laboratory stressor upon the typical diurnal pattern of HPA activation and relationship to acute cortisol secretion. A sample of 23 healthy young adults provided salivary cortisol samples at four time points (immediately upon awakening, 30-min post-awakening, 1200 h and before bed) on 2 consecutive days. On the second day, participants attended the laboratory and undertook an anticipated acute socially evaluative stressor immediately following provision of their 1200 h saliva sample. Heart rate, blood pressure and mood were recorded immediately before and after the stressor and at 10 and 20 min post-stressor along with additional salivary cortisol samples. Typical patterns of cortisol secretion were observed on both days and exposure to the laboratory stressor was associated with the expected increases in cortisol, heart rate, blood pressure and negative mood. However, significant differences in diurnal cortisol secretion were observed between the two days with greater secretion, in particular, during the period following awakening, evident on the day of the anticipated laboratory stressor. Furthermore, secretion of cortisol during the period following awakening was positively related to secretion during the acute reactivity periods. This is the first study to integrate a laboratory stressor into a typical day and assess its impact on indices of diurnal cortisol secretion in an ambulatory setting. The current findings support the notion that the cortisol awakening response is associated with anticipation of the upcoming day and the subsequent demands required of the individual.
在健康、未受挑战的个体中，皮质醇的分泌通常呈现出一种昼夜节律，其特征是醒来后的一段时间内达到峰值（皮质醇觉醒反应），并在一天中逐渐下降。此外，皮质醇分泌会因急性应激刺激而增加，尤其是涉及社会评价的应激源。本研究首次评估了预期的急性实验室应激源对下丘脑-垂体-肾上腺（HPA）轴激活的典型昼夜模式的影响以及与急性皮质醇分泌的关系。23名健康年轻成年人的样本在连续两天的四个时间点（醒来后立即、醒来后30分钟、12:00和睡前）提供唾液皮质醇样本。第二天，参与者在提供12:00的唾液样本后立即进入实验室，接受预期的急性社会评价应激源。在应激源前后以及应激源后10分钟和20分钟记录心率、血压和情绪，并采集额外的唾液皮质醇样本。两天均观察到典型的皮质醇分泌模式，接触实验室应激源与皮质醇、心率、血压和负面情绪的预期增加有关。然而，两天之间观察到昼夜皮质醇分泌存在显著差异，在预期实验室应激源当天，尤其是醒来后的时间段内，分泌量更大。此外，醒来后时间段内的皮质醇分泌与急性反应期的分泌呈正相关。这是第一项将实验室应激源纳入日常并评估其对动态环境中昼夜皮质醇分泌指标影响的研究。目前的研究结果支持这样一种观点，即皮质醇觉醒反应与对即将到来的一天的预期以及个体随后所需面对的要求有关。
