Moderie Christophe, Van der Maren Solenne, Paquet Jean, Dumont Marie
Center for Advanced Research in Sleep Medicine, Sacre-Coeur Hospital, CIUSSS-NIM, Montreal, Quebec, Canada.
Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
Nat Sci Sleep. 2020 Jun 25;12:365-375. doi: 10.2147/NSS.S251743. eCollection 2020.
Individuals complaining of a delayed sleep schedule are expected to have shorter sleep duration and lower sleep quality when they must comply with morning obligations. The changes in the sleep schedule imposed by morning obligations may in turn decrease the stability and amplitude of their rest-activity cycle. These expectations were only partially supported in previous studies, possibly due to poor differentiation between days with mandatory or free wake times.
Fourteen college/university students (8 women) with a complaint of a late sleep schedule and a bedtime after midnight were compared to fourteen controls with an earlier sleep schedule and no complaint.
During a week of 24-h activity recording, participants specified in their sleep diary whether their wake time was free or determined by an obligation.
The number of nights with mandatory wake times was similar in the two groups. Groups were also similar for sleep duration and sleep quality over the 7 days of recording. Actigraphic sleep efficiency was the same in the two groups for both free and mandatory wake times, but subjective sleep quality decreased on the nights with mandatory wake time in both groups. On the nights with mandatory wake time, delayed participants had shorter sleep episodes and less total sleep time than controls. Rest-activity cycle amplitude was lower in the delayed group whether wake time was free or mandatory.
Sleep duration and total sleep time differed between the two groups only when wake time was mandatory. Prior to mandatory wake times, delayed participants kept the same bedtime and shortened their sleep; sleep latency and sleep efficiency were preserved but subjective sleep quality and alertness on awakening decreased compared to nights with free wake time. Lower amplitude of the rest-activity cycle in delayed subjects may reflect lifestyle differences compared to control participants.
那些抱怨睡眠时间表延迟的人，在必须遵守早晨的事务安排时，预计睡眠时间会更短，睡眠质量会更低。早晨事务安排所带来的睡眠时间表变化，反过来可能会降低他们休息 - 活动周期的稳定性和幅度。这些预期在之前的研究中仅得到部分支持，可能是由于在有强制唤醒时间或自由唤醒时间的日子之间区分不佳。
14名抱怨睡眠时间表延迟且午夜后才睡觉的大学生（8名女性）与14名睡眠时间表更早且无此类抱怨的对照组进行了比较。
在为期一周的24小时活动记录期间，参与者在他们的睡眠日记中指明其唤醒时间是自由的还是由事务安排决定的。
两组中具有强制唤醒时间的夜晚数量相似。在记录的7天里，两组在睡眠时间和睡眠质量方面也相似。对于自由和强制唤醒时间，两组的活动记录仪睡眠效率相同，但两组在有强制唤醒时间的夜晚主观睡眠质量均下降。在有强制唤醒时间的夜晚，睡眠时间表延迟的参与者比对照组的睡眠时段更短，总睡眠时间更少。无论唤醒时间是自由还是强制，延迟组的休息 - 活动周期幅度都更低。
只有当唤醒时间是强制的时候，两组之间的睡眠时间和总睡眠时间才存在差异。在强制唤醒时间之前，睡眠时间表延迟的参与者保持相同的就寝时间并缩短了睡眠时间；睡眠潜伏期和睡眠效率得以保留，但与自由唤醒时间的夜晚相比，主观睡眠质量和醒来时的警觉性下降。与对照组参与者相比，睡眠时间表延迟的受试者休息 - 活动周期幅度更低可能反映了生活方式的差异。
