A recent article in Sleep suggests that sleep interruptions are more detrimental on mood than overall reductions in sleep duration. Researchers at John Hopkins University subjected 62 healthy men and women to a randomized trial including 3 arms: three consecutive nights of forced awakenings (8 times per night), delayed bedtimes or uninterrupted sleep. Outcomes included sleep architecture (polysomnography) and a standard mood questionnaire. Participants subjected to forced awakenings had a 31% reduction in positive mood, while the delayed bedtime group had a decline of 12% compared to the first day. Researchers did not find significant differences in negative mood between these two groups. These findings suggest a “putative biologic mechanism (slow wave sleep deficit) that could help explain the strong comorbidity between insomnia and depression.”
This research asks provocative questions regarding the approach to sleep during residency training. Extended call duration (i.e. 24-28 hour in house call) is associated with frequent episodes of sleep interruption and, therefore, may be more detrimental to psychological well being when compared to shift work (only associated with reduced sleep duration). We cannot draw conclusions regarding educational benefit or patient safety, but, with ongoing controversy regarding resident work hour restrictions, this study surely provides food for thought.