Leibniz Centre for Working Environment and Human Factors at TU Dortmund (Leibniz-Institut für Arbeitsforschung and der TU Dortmund), Ardeystr. 67, 44139 Dortmund, Germany.
Psychoneuroendocrinology. 2010 Nov;35(10):1501-9. doi: 10.1016/j.psyneuen.2010.05.002. Epub 2010 Jun 8.
This study tested the hypothesis that the cortisol awakening response (CAR) and the cortisol shift profile normalize with successive night shifts due to the shift of the circadian system. 18 students (9 women, 9 men, 19-29 years), worked first four consecutive morning- and then four consecutive night shifts. Each work shift was preceded by an 8-h sleep opportunity meaning that the sleep-activity cycle was advanced by 8 h. The advance of the circadian system was promoted by a 2-h bright light pulse at the end of each night shift and quantified by 24-h phase assessment procedures (PA) before and after the four day shifts and again after the four night shifts. Saliva samples were taken 0, 15, 30, 45, and 60 min post-awakening, hourly during each work shift and each PA. During the night shift sequence, the CAR, indicated by the area under curve with respect to increase (AUC(I)), increased gradually across the 4-day sleep periods. Baseline levels were reached after 3 days in men and 4 days in women. The increase of the CAR was associated with a gradually increasing decline of cortisol levels during the night shifts. This adjustment was--at least not only--related to the advance of the circadian system which was 5 h. A contributor to the increase of the CAR might be the anticipation of the upcoming demands of the following work shifts.
这项研究检验了这样一个假设，即由于生物钟系统的移位，皮质醇觉醒反应（CAR）和皮质醇变化曲线会随着连续夜班而正常化。18 名学生（9 名女性，9 名男性，19-29 岁），首先连续上四个早班，然后连续上四个夜班。每个工作班次之前都有 8 小时的睡眠机会，这意味着睡眠-活动周期提前了 8 小时。生物钟系统的提前通过每个夜班结束时的 2 小时强光脉冲来促进，并通过四天轮班前后和四天轮班后的 24 小时相位评估程序（PA）进行量化。唾液样本在觉醒后 0、15、30、45 和 60 分钟以及每个工作班次和每个 PA 期间每小时采集一次。在夜班序列中，通过与增加相关的曲线下面积（AUC（I）），CAR 在 4 天的睡眠期逐渐增加。男性在第 3 天，女性在第 4 天达到基线水平。CAR 的增加与夜间皮质醇水平的逐渐下降有关。这种调整至少不仅与生物钟系统的提前 5 小时有关。CAR 增加的一个原因可能是对即将到来的下一个工作班次需求的预期。
