REVIEW OF: Cheng WJ et al, Sleep 2022;45(4):zsac034

STUDY TYPE: Randomized crossover design

Night shift work is an occupational hazard. One in five shift workers have problems with sleep, attention, and wakefulness that qualify for a diagnosis of shift-work disorder. Management of this disorder involves appropriate timing of light and darkness, but no one has looked at the question of when sleep should occur. This study examined that issue by comparing morning sleep (ie, after the night shift) to evening sleep (ie, before the night shift) in people with shift-work disorder.

Sixty adults were randomized to a morning (9 am–5 pm) or an evening (3–11 pm) sleep schedule for the first week of the intervention, crossing over to the other schedule for the second week (30 in each arm). The average age was 30 years, 80% were women, and 66% worked as night-shift nurses. The diagnosis of shift-work disorder was made with ICSD-3 criteria and confirmed by a 14-day sleep log. Adherence to the protocol was monitored with daily sleep and actigraphy data. No participants used prescribed sleep aids or stimulants during the study period.

The evening sleep protocol resulted in a 30-minute longer duration of sleep (5.3 vs 4.8 hours) as well as improvements in sleep quality and daytime somnolence throughout the week. Attention also improved, but only on the day after the first shift. The evening protocol was particularly effective for subjects with an evening chronotype (eg, “night owls”).

CARLAT TAKE

Ask your patients who work the night shift whether they sleep before or after their shift. If a later sleep schedule is compatible with their social and family life, start a conversation about the potential benefits of sleeping in the later part of the day so they wake about an hour before their shift.