Sano A, Phillips AJ, McHill AW, Taylor S, Barger LK, Czeisler CA, Picard RW. "Influence of Weekly Sleep Regularity on Self-Reported Wellbeing," Sleep2017, June 2017.

Abstract

Introduction

Irregular sleep-wake schedules are commonplace in modern society. Recent studies have indicated the importance of sleep regularity, in addition to sleep duration. We studied in college students how weekly sleep regularity is predictive of daily self-reported happiness, healthiness and calmness, during one week and on the first day following that week. 

Methods

204 college students (aged 18–25, 132 male) participated in a 30-day field study. Sleep timing and duration were monitored using both actigraphy and daily morning and evening Internet-based diaries. Self-reports of wellbeing (happiness, healthiness, and calmness) were collected via daily diaries, morning and evening, with non-numeric visual-analog scales. The sleep regularity index was computed weekly, as the likelihood of being awake or asleep across all time-points 24-hours apart. We used generalized estimating equations that controlled for weekly average sleep duration to examine how sleep regularity relates with self-reported wellbeing. We also examined how the three wellbeing measures change with sleep regularity transitions (e.g. regular to irregular, irregular to regular) both in participants who had <7 hours and >= 7 hours average sleep duration. Bonferroni corrections were made for all analyses.

Results

Higher sleep regularity was statistically significantly related to higher morning and evening happiness, healthiness and calmness (p < 0.01) during the week. On the first day following the week, these results hold (p<0.01) for all but morning healthiness. For the sleep regularity weekly transitions, in sleepers who averaged < 7 hours, the irregular-regular sleep transition showed a greater increase in morning happiness and calmness (p < 0.01), and evening calmness (p < 0.01) than the regular-regular sleep transition.

Conclusion

Regular sleep patterns were found to be associated with better wellbeing in college students. A transition from irregular to regular weekly sleep patterns was associated with improved happiness and calmness both during the week of regular sleep and on the day following it. This work underlines the necessity of considering sleep regularity, in addition to sleep duration, as an important factor for understanding self-reported wellbeing.