Furman University, United States.
Furman University, United States.
Psychoneuroendocrinology. 2020 Apr;114:104584. doi: 10.1016/j.psyneuen.2020.104584. Epub 2020 Jan 10.
To examine whether cumulative cortisol production changes during a period of increased demands when cortisol and stress are assessed concurrently. The study also compared stress perceptions vs. cumulative stressful events on their respective association with cortisol output. Finally, it explored whether certain types of stressful events, those involving school/job performance or social-evaluative threat, were linked to cortisol levels across multiple weeks.
The current study assessed cumulative cortisol production via hair sample in 56 undergraduates (88 % female) during both lower stress (summer break) and higher stress (academic term) periods. During the latter, both negative events (checklist) and stress perceptions were assessed weekly, and these reports were aggregated across the 10-weeks to minimize retrospective bias.
Cortisol levels in hair samples were significantly higher (d = 0.84) during the academic term (M = 14.24 pg/mg, SD = 11.36) compared to summer break (M = 8.00 pg/mg, SD = 4.14), suggesting greater cumulative exposure to cortisol. Although perceived stress was not associated with cortisol levels (r(53) = .10, p = 0.46), exposure to more stressful events (r(53) = .27, p = 0.047), particularly events involving academic demands (r(53) = .37, p = 0.006), or negative evaluation/social rejection (r(53) = .27, p = 0.045), was positively associated with cumulative cortisol exposure.
This study demonstrates that cortisol levels in hair may be linked to cumulative exposure to stressors when measured concurrently (3 months), and that stressful events, rather than perceptions, are reflected in HPA axis activity. Real-world stressors involving performance demands and social-evaluative threat accumulate to enhance cortisol production, consistent with their acute HPA effects in the lab. Hair samples may provide a window into the past by allowing researchers to feasibly assess cortisol production before, during, and after the onset of a chronic stressor.
考察在同时评估皮质醇和应激时，需求增加期间皮质醇累积产生是否发生变化。本研究还比较了应激感知与累积应激事件各自与皮质醇分泌的相关性。最后，探讨了某些类型的应激事件，如涉及学校/工作表现或社会评价威胁的事件，是否与跨多个星期的皮质醇水平有关。
本研究通过 56 名本科生（88%为女性）的头发样本评估了皮质醇的累积产生，这些本科生分别处于低应激（暑假）和高应激（学期中）时期。在后一时期，每周评估负面事件（清单）和应激感知，为尽量减少回溯偏差，这些报告在 10 周内进行汇总。
头发样本中的皮质醇水平在学期中（M=14.24pg/mg，SD=11.36）显著高于暑假（M=8.00pg/mg，SD=4.14），表明皮质醇的累积暴露量更大。尽管感知到的压力与皮质醇水平无关（r（53）=0.10，p=0.46），但经历更多的应激事件（r（53）=0.27，p=0.047），特别是涉及学业要求的事件（r（53）=0.37，p=0.006）或负面评价/社会排斥（r（53）=0.27，p=0.045），与累积皮质醇暴露量呈正相关。
本研究表明，当同时（3 个月）测量时，头发中的皮质醇水平可能与应激源的累积暴露有关，而应激事件，而不是感知，反映了 HPA 轴的活动。涉及表现要求和社会评价威胁的现实世界应激源会累积起来增强皮质醇的产生，这与它们在实验室中的急性 HPA 效应一致。头发样本可以通过让研究人员在慢性应激源出现之前、期间和之后，切实地评估皮质醇的产生，为过去提供一个窗口。
