Lingering impacts on sleep following the Daylight Savings Time transition in the Project Baseline Health Study

Abstract

Background The “spring forward” change to Daylight Savings Time (DST) has been epidemiologically linked with numerous health and safety risks in the days following the transition, but direct measures of sleep are infrequently collected in free-living individuals. Methods The Project Baseline Health Study (PBHS), a prospective, multicenter, longitudinal representative U.S. cohort study that began in 2017 launched a Sleep Mission in March 2021 to characterize sleep using patient-reported and wearable device measures, in free-living circumstances during the DST switch. Estimated sleep period duration, subjective restedness, and sleep quality were compared before and after the DST transition during specified timeframes. Results Of the total PBHS population of 2502 participants, 912 participants received an invitation and 607 responded by March 6th. Among those, 420 participants opted into the Sleep Mission (69.2%). The transition to DST resulted in both acute and lingering impacts on sleep. Acute effects included a 29.6 min reduction in sleep period (p = 0.03), increases in the proportion of patients who reported ‘sleeping poorly’ (from 1.7 to 13.6% [p < 0.01]), and with scores falling into the ‘unrested’ category (from 1.7 to 8.5% [p = 0.046]). There was also a downward trend in the proportion of participants reporting being rested in the morning following the DST transition (from 62.7% on March 7 to 49.2% on March 14 [p = 0.10]). Lingering effects included a 18.7% relative decrease in the daily likelihood of participants reporting restedness (from 49.2% in the week prior to the DST transition to 40.0% in the week after [p < 0.01]). Conclusion The DST transition is associated with an acute reduction in sleep period, as well as an increased proportion of individuals reporting poor sleep and unrestedness. The DST transition also resulted in lingering impacts on self-reported restedness, lasting into the week following the transition. This work adds to a growing understanding of the persistence of impacts on sleep health metrics due to the DST transition.

The effects of daylight saving time clock changes on accelerometer-measured sleep duration in the UK Biobank

“…These results suggest that the Spring transition is associated with reduced sleep duration. It is difficult to directly compare our results which look at sleep duration each day (from midnight to midnight), to studies that examine sleep each night (from noon to noon) 10, 12 . However, we found a loss of sleep greater than that seen in previous studies which have reported a 5-30 minute reduction in sleep duration on the night of the Spring clock change 10, 12 and a study reporting a 30 minute reduction on the Sunday of the change 11 .…”

“…Many studies of the effects of DST transitions on sleep have relied on subjective self-report data 10, 11, 14, 15, 19, 20 , which may be affected by recall bias and have been shown to only moderately correspond to more objective measures of sleep, such as actigraphy 26 . Whilst some DST research has used actigraphy data, most of these studies have suffered from small sample sizes (n < 100) 13, 16–18 , reducing their estimates’ precision.…”

“…However, estimates of the exact effects of clock changes on sleep duration vary. Studies report that sleep duration on the night of the Spring clock change was 5 -30 minutes less than on the same night on surrounding weekends [10][11][12] , whilst estimates of sleep duration on the night of the Autumn clock change range from no difference to 40 minutes more than the surrounding weekends [11][12][13][14] . Some studies report that sleep duration on the weekdays after the Spring changes is up to 60 minutes less than surrounding weeks, whilst others report that it is up to 28 minutes more 11, 14-19 .…”

“…Estimates of sleep duration on the weekdays after the Autumn changes are also conflicting, with some studies estimating that it is up to 25 minutes less than surrounding weeks, whilst other studies report it being up to 11 minutes more 11,14,15,17,20 . Many studies of the effects of DST transitions on sleep have relied on subjective self-report data 10,11,14,15,19,20 , which may be affected by recall bias and have been shown to only moderately correspond to more objective measures of sleep, such as actigraphy…”

Improving adjustment to daylight saving time transitions with light

“…DST was originally designed and promoted for individuals with outdoor lifestyles by increasing their daylight exposure. In contemporary society, human spend most of their time indoors (on average 87% 1 ), where they may experience limited exposure to natural light and are particularly susceptible to the effects of DST transitions, which can disrupt circadian rhythms and impair sleep duration and quality 2 – 5 . These effects may persist for several days after the shift, or even longer 6 .…”