Institute for Medical Psychology, Department of Human Chronobiology, Ludwig-Maximilians-University, Munich, Germany.
Programa de Pós-Graduação em Psiquiatria e Ciências do Comportamento. UFRGS, Porto Alegre, Brazil.
Sleep. 2018 May 1;41(5). doi: 10.1093/sleep/zsy029.
The Pittsburgh Sleep Quality Index (PSQI) is the most common measure of sleep quality. Its questions refer to "usual" sleep habits during the last month. Considering how different sleep-wake behavior can be between workdays and work-free days, we hypothesized that sleep quality should show similar differences. We investigated these potential differences in a cross-sectional online study using the original and two adapted versions of the PSQI that replaced "usual" by explicitly referring to sleep on workdays or work-free days. Additionally, we investigated how these scores relate to chronotype and social jetlag assessed by the Munich ChronoType Questionnaire. Participants were recruited online, they had to be older than 18 years, following regular weekly work schedules, and they should not be shift workers. Repeated-measures analysis of variance was used to compare the three different versions of the PSQI (usual, work, and work-free). To find out whether PSQI score differences could be predicted by chronotype and/or social jetlag a mediation analysis was carried out. Workday PSQI scores were similar to the original "usual" scores, two points higher than the PSQI score on work-free days and above the cutoff designating poor sleep quality. PSQI components and time variables also differed between workdays and work-free days. Chronotype correlated with the difference between PSQI scores on workdays and on work-free days, an association mediated by social jetlag. Our results suggest that the original PSQI predominantly reports sleep quality on workdays and that work schedules may affect sleep quality. The mediation of social jetlag on the association of chronotype and PSQI score differences could mean that not chronotype per se, but rather the collision of an individuals' chronotype with fixed work schedules explains the differences between sleep on workdays and work-free days. Understanding how sleep quality differs between workdays and work-free days, how this difference can adequately be assessed through directing participants to focus on their sleep specifically on workdays vs. work-free days, and how circadian factors modulate this difference, is crucial to improve sleep quality.
匹兹堡睡眠质量指数（PSQI）是最常用的睡眠质量衡量标准。它的问题是指“通常”在过去一个月的睡眠习惯。考虑到工作日和休息日之间的睡眠-觉醒行为可能有很大的不同，我们假设睡眠质量应该显示出类似的差异。我们使用 PSQI 的原始版本和两个经过改编的版本进行了横断面在线研究，这两个版本分别明确提到了工作日或休息日的睡眠，以调查这些潜在的差异。此外，我们还研究了这些分数与通过慕尼黑时间类型问卷评估的时间类型和社会时差的关系。参与者是通过在线招募的，他们必须年满 18 岁，遵循规律的每周工作时间表，并且不能是轮班工人。重复测量方差分析用于比较 PSQI 的三个不同版本（通常、工作和休息）。为了找出 PSQI 分数的差异是否可以由时间类型和/或社会时差来预测，我们进行了中介分析。工作日 PSQI 分数与原始的“通常”分数相似，比休息日的 PSQI 分数高两分，高于表示睡眠质量差的临界值。PSQI 成分和时间变量在工作日和休息日之间也有所不同。时间类型与工作日和休息日 PSQI 分数之间的差异相关，这种关联由社会时差介导。我们的结果表明，原始 PSQI 主要报告工作日的睡眠质量，并且工作时间表可能会影响睡眠质量。社会时差对时间类型和 PSQI 分数差异之间关联的中介作用可能意味着，不是时间类型本身，而是个体的时间类型与固定的工作时间表的冲突，解释了工作日和休息日之间的睡眠差异。了解工作日和休息日之间的睡眠质量差异、如何通过引导参与者专注于他们在工作日和休息日的具体睡眠来充分评估这种差异，以及如何调节昼夜节律因素来改变这种差异，对于改善睡眠质量至关重要。
