0249 Individual differences of sleep pattern and duration between two consecutive night shifts among night workers

Abstract

Abstract Introduction Working at night leads to shortened and disturbed daytime sleep. Night workers usually adopt one of several sleep patterns between consecutive nights: sleeping right after night work (morning sleep), delaying sleep to the afternoon (afternoon sleep), or dividing sleep into two or more episodes (split sleep). However, few studies have examined sleep pattern and duration between consecutive nights in real-world workers. The objective of this study was to examine individual differences in sleep pattern and duration when working consecutive night shifts. Methods Night workers (n=241, 43.0±16.5y, 67.2% female) from various occupations who reported working consecutive nights completed an online survey. The survey included questions on socio-demographics and daytime sleep and nap schedules. Sleep pattern (morning vs. afternoon vs. split) and total sleep time (sleep+naps) were derived from survey responses. Cross-tabulations and ANOVA were conducted. Results On average, night workers reported a total daytime sleep of 5.37±2.69 hours (range 0-14.25 hours). 65.1% reported morning sleep, 10% afternoon sleep, and 24.9% split sleep. Split sleepers (6.78±2.13 hours) reported longer total sleep than morning (4.86±2.75 hours) or afternoon (5.11±2.37 hours) sleepers. Younger age (< 50y), single marital status, shorter night shift tenure (≤10 years), working ≤3 consecutive shifts, and having ill or disabled dependents were associated with greater prevalence of morning sleep; older age (≥50y), married or separated/widowed, >10 years night shift tenure, working ≥4 consecutive shifts, and having no dependents were associated with greater prevalence of afternoon or split sleep. Having childcare responsibility was associated with more split sleep than no children. Similarly, younger age (< 50y), singles, shorter night shift tenure, working three or fewer consecutive shifts, having ill or disabled dependents, and having a second job were associated with shorter total sleep. However, having childcare responsibility was associated with greater total sleep. Conclusion Sleep timing and duration between consecutive nights were influenced by age, marital status, dependents, night work tenure, and number of consecutive night shifts. Future studies are needed to explore what sleep pattern is most beneficial for sleep, performance, safety, and health outcomes of these workers. Support (if any) The study was supported by grant R01 AG044416 from the US National Institutes of Health.