LAUSR

Daylight saving time (DST) imposes a twice yearly 1h change in local clock time. Although it may seem a small adjustment, there is increasing awareness of the potential acute and long term effects at the individual and population level. Several studies have shown detrimental effects on sleep patterns, but mostly focusing on adults. Only one study has looked at the effect in infants’ sleep of change from standard time (ST) to DST, reporting negative effects. One study limitation was the reliance on parental reports of infant sleep. In addition, effects of the change from DST to ST are unknown. We hypothesize that the change from DST to ST would lead to earlier rise times, leading to sleep loss in the week following the change. Caregivers of 510 children ages 3-24 mos (M=9.8 mos) tracked their child’s sleep using Nanit baby-monitor. Sleep metrics analyzed were: Nighttime sleep duration (NSD) and midpoint, number of night-wakings and sleep efficiency. Wilcoxon rank sum tests compared the average of each sleep metric for the week preceding the time change (Oct 31st-Nov 4th 2022, Baseline) with sleep metrics for each night of the following week (Nov 7-11 2022, post-DST week). Analyses were repeated stratifying by age group (4-6,7-12 and 13-24 months). After the time change, there was no change in NSD or sleep efficiency. There was a significant decrease in the number of night-wakings for infants 3-6 months, with an average of 0.5 fewer wakings per night compared to Baseline (Baseline mean=5 wakings). Midpoint was significantly earlier for all ages by an average of 10min, every day of the post-DST week. The return to ST affected infants’ sleep midpoint. Observed effects were minor compared to those reported in previous literature for the ST to DST change, in line with other fields like cardiovascular health. This easier adjustment could be attributed to the fact that during DST there is an increased mismatch between body clock and social clock time, thus infants more readily adjust to a return to ST which minimizes this mismatch. This research was supported by Nanit