Department of Sleep and Human Factors, Institute for Aerospace Medicine, German Aerospace Center, Cologne, Germany.
Institute of Medical Psychology, Ludwig Maximilian University of Munich, Munich, Germany.
J Biol Rhythms. 2021 Aug;36(4):395-409. doi: 10.1177/07487304211006073. Epub 2021 Apr 20.
The study aimed to explore chronotype-specific effects of two versus four consecutive morning or night shifts on sleep-wake behavior. Sleep debt and social jetlag (a behavioral proxy of circadian misalignment) were estimated from sleep diary data collected for 5 weeks in a within-subject field study of 30 rotating night shift workers (29.9 ± 7.3 years, 60% female). Mixed models were used to examine whether effects of shift sequence length on sleep are dependent on chronotype, testing the interaction between sequence length (two vs. four) and chronotype (determined from sleep diaries). Analyses of two versus four morning shifts showed no significant interaction effects with chronotype. In contrast, increasing the number of night shifts from two to four increased sleep debt in early chronotypes, but decreased sleep debt in late types, with no change in intermediate ones. In early types, the higher sleep debt was due to accumulated sleep loss over four night shifts. In late types, sleep duration did not increase over the course of four night shifts, so that adaptation is unlikely to explain the observed lower sleep debt. Late types instead had increased sleep debt after two night shifts, which was carried over from two preceding morning shifts in this schedule. Including naps did not change the findings. Social jetlag was unaffected by the number of consecutive night shifts. Our results suggest that consecutive night shifts should be limited in early types. For other chronotypes, working four night shifts might be a beneficial alternative to working two morning and two night shifts. Studies should record shift sequences in rotating schedules.
这项研究旨在探讨两种连续的早班或夜班与四种连续的早班或夜班对睡眠-觉醒行为的影响。通过对 30 名轮班夜班工人（29.9±7.3 岁，60%为女性）进行为期 5 周的现场研究，从睡眠日记中收集了睡眠债务和社会时差（昼夜节律失调的行为替代物）的数据。混合模型用于检验睡眠中轮班顺序长度的影响是否取决于昼夜类型，检验了序列长度（两种与四种）和昼夜类型（从睡眠日记中确定）之间的相互作用。与昼夜类型相比，两种与四种早班的分析显示，轮班顺序长度的影响没有显著的交互作用。相比之下，将夜班的数量从两个增加到四个，会导致早期类型的睡眠债务增加，但晚期类型的睡眠债务减少，而中间类型的睡眠债务没有变化。在早期类型中，较高的睡眠债务是由于四个夜班中累积的睡眠损失。在晚期类型中，在四个夜班期间，睡眠时间没有增加，因此适应不太可能解释观察到的较低的睡眠债务。在两种夜班之后，晚期类型的睡眠债务反而增加了，这是由于这种轮班制度中前两个早班的影响。包括小睡也没有改变这些发现。社会时差不受连续夜班数量的影响。我们的结果表明，连续的夜班应在早期类型中受到限制。对于其他昼夜类型，连续工作四个夜班可能是替代两个早班和两个夜班的有益选择。研究应记录轮班制度中的轮班顺序。
