Boivin Diane B, James Francine O
Centre for Study and Treatment of Circadian Rhythms, Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montréal, Québec H4H 1R3, Canada.
J Biol Rhythms. 2002 Dec;17(6):556-67. doi: 10.1177/0748730402238238.
In this combined field and laboratory investigation, the authors tested the efficacy of an intervention designed to promote circadian adaptation to night-shift work. Fifteen nurses working permanent night schedules (> or = 8 shifts/ 15 days) were recruited from area hospitals. Following avacation period of > or = 10 days on a regular daytime schedule, workers were admitted to the laboratory for the assessment of circadian phase via a 36-h constant routine. They returned to work approximately 12 night shifts on their regular schedules under one of two conditions. Treatment group workers (n = 10, mean age +/- SD = 41.7 +/- 8.8 years) received an intervention including 6 h of intermittent bright-light exposure in the workplace (approximately 3,243 lux) and shielding from bright morning outdoor light with tinted goggles (15% visual light transmission). Control group workers (n = 9, mean age +/- SD = 42.0 +/- 7.2 years) were observed in their habitual work environments. On work days, participants maintained regular sleep/wake schedules including a single 8-h sleep/darkness episode beginning 2 h after the end of the night shift. A second 36-h constant routine was performed following the series of night shifts. In the presence of the intervention, circadian rhythms of core body temperature and salivary melatonin cycles were delayed by an average (+/- SEM) of -9.32 +/- 1.06 h and -11.31 +/- 1.13 h, respectively. These were significantly greater than the phase delays of -4.09 +/- 1.94 h and -5.08 +/- 2.32 h displayed by the control group (p = 0.03 and p = 0.02, respectively). The phase angle between circadian markers and the shifted schedule was reestablished to its baseline position only in the treatment group of workers. These results support the efficacy of a practical intervention for promoting circadian adaptation to night-shift work under field conditions. They also underline the importance of controlling the overall pattern of exposure to light and darkness in circadian adaptation to shifted sleep/wake schedules.
在这项结合了实地研究和实验室研究的调查中，作者测试了一种旨在促进昼夜节律适应夜班工作的干预措施的效果。从当地医院招募了15名长期值夜班（≥8个班次/15天）的护士。在按照常规白天作息时间表休假≥10天后，这些工作人员进入实验室，通过36小时的固定程序来评估昼夜节律相位。他们在两种条件之一的情况下，按照常规时间表返回工作岗位，值大约12个夜班。治疗组工作人员（n = 10，平均年龄±标准差 = 41.7 ± 8.8岁）接受了一项干预措施，包括在工作场所进行6小时的间歇性强光照射（约3243勒克斯），并用有色护目镜遮挡早晨明亮的户外光线（视觉光透射率为15%）。对照组工作人员（n = 9，平均年龄±标准差 = 42.0 ± 7.2岁）在其习惯的工作环境中接受观察。在工作日，参与者保持规律的睡眠/觉醒时间表，包括在夜班结束后2小时开始的一次8小时睡眠/黑暗时段。在一系列夜班之后进行了第二次36小时的固定程序。在有干预措施的情况下，核心体温和唾液褪黑素周期的昼夜节律分别平均（±标准误）延迟了-9.32 ± 1.06小时和-11.31 ± 1.13小时。这些延迟显著大于对照组显示的-4.09 ± 1.94小时和-5.08 ± 2.32小时的相位延迟（分别为p = 0.03和p = 0.02）。只有在治疗组工作人员中，昼夜节律标志物与改变后的时间表之间的相位角才重新建立到其基线位置。这些结果支持了一种实用干预措施在实地条件下促进昼夜节律适应夜班工作的效果。它们还强调了在昼夜节律适应改变后的睡眠/觉醒时间表中控制整体光照和黑暗暴露模式的重要性。
