O001 Preschoolers’ bedtime activities and subsequent sleep: a wearable camera studys

Abstract Introduction Bedtime routines are recommended for young children’s sleep. Most supporting evidence is, however, subjective, and the effects of constituent activities are rarely examined. This study explored pre-bedtime activity and sleep associations using objective measures. Methods In this repeated-measures observational study, 70 healthy 3–4-year-old children wore AX3 actigraphs for seven nights with chest-worn GoPros videoing activities for 2h before bed for five of those nights. Nutrition, self-care, screen, story, and other connection activity data were extracted using a reliable coding scheme developed for this study (κ ≥ 0.8). Exploratory analyses using Bayesian mixed effects linear and Poisson regression investigated associations between activities in the hour before bedtime and that night’s actigraphy-derived sleep measurements. Results Total sleep time (TST) was greater when the pre-bedtime period included connection activities like cuddling (16 min Bayesian 95% credible interval (CrI) -11, 43; 88% chance of a positive association) or bath/shower (15 min 95%CrI -9, 38; 89% chance of a positive association). Screen exposure showed the least evidence of a relationship (TST 1 min shorter per 10 mins of exposure 95%CrI -6, 5). Credible intervals were wide for audiobook use, which was uncommon, although directionality suggested less TST (-42 min 95%CrI -97, 15; 93% chance of a negative association). Adjusting for sociodemographic factors did not substantially change results. Discussion Findings are consistent with connection activities involving caregivers supporting young children’s sleep, but that screen exposure is not a meaningful predictor when measured objectively. Further research on audiobook use is needed, including for reverse causation.