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

Introduction: Daylight saving time (DST) clock changes have been associated
with sleep loss for around a week after the transitions. However,
many studies have relied on subjective self-report data, which may be
affected by recall bias. Furthermore, estimates from more objective,
accelerometer-measured sleep studies have lacked precision due to
small sample sizes. We aimed to explore the effects of DST clock
changes on sleep duration in a large accelerometer dataset.

Method: UK Biobank participants (n = 11,780; aged 43–78) wore
accelerometers for one or more days during the two-week period surrounding
the Spring and Autumn DST transitions between October
2013 and November 2015. Between-individual t tests compared sleep
duration on the Sunday (midnight to midnight) of the clock changes to
the Sunday before and the Sunday after. Linear regression analyses
compared sleep duration between individuals on the Monday to
Saturday before and after the transitions (Mon before vs. Mon
after etc.).

Results: In Spring, mean sleep duration was 65 min lower on the
Sunday of the clock changes than the Sunday before (95% CI -72 to
-58 min) and 61 min lower than the Sunday after (95% CI -69 to
-53). It was 10 min higher on the Wednesday after the clock change
than the Wednesday before (95% CI 3 to 17 min), 19 min higher on
the Friday after than the Friday before (95% CI 11 to 27 min) and
10 min lower on the Saturday after than the Saturday before (95% CI
-20 to -1 min). In Autumn, mean sleep duration on the Sunday of
the clock changes was 33 min higher than the Sunday before (95% CI
27 to 39 min) and 38 min higher than the Sunday after (95% CI 32 to
43 min). There were no detectable differences, before and after the
transition, for other days in Autumn.

Conclusion: The Spring DST transition was associated with an acute
reduction in sleep duration on the Sunday of the clock change. However,
the effect was short lived, with sleep on the following weekdays
not adversely affected. Future research should use a large accelerometer
dataset to explore the timing of sleep over the clock changes.

Conflict of Interest: No.