674 Changes in Objectively-Measured Adolescent Sleep and Light Exposure During the COVID-19 Pandemic

Abstract

Introduction: U.S. adolescents have high rates of insufficient sleep. School closures and stay-at-home orders were implemented to mitigate disease spread during the Coronavirus 2019 (COVID-19) pandemic. Without the restriction of imposed early school start times, we hypothesized that adolescents would have longer, later, and less variable sleep compared to pre-COVID-19. We further hypothesized these changes would be associated with increased and later light exposure. Method(s): High school students age 14-19 years with <7h sleep on school nights completed two weeks of at-home monitoring. The Pre-COVID-19 week took place between October 2018-February 2020 and the COVID-19 week occurred in May 2020 during statewide stay-at-home orders. Participants wore an accelerometer to assess sleep and light exposure while completing a concurrent sleep log. Paired-samples t-tests examined differences in sleep and light between Pre-COVID-19 and COVID-19. Pearson correlations assessed associations between change in sleep and change in light. Result(s): Participants (N=16) were 16.5 +/-1.2-years-old at Pre- COVID-19, 70.6% female, 68.8% White, and 25.1% Hispanic. Youth were participating in online learning due to in-person school closures and only 2 participants (14.3%) had a set start time, while the remainder reported learning per their own schedule. Youth obtained approximately one hour more weekday sleep per night during the COVID-19 week compared to Pre-COVID-19 (p<0.001). Bed and waketimes were significantly delayed on weekdays and weekends during COVID-19 compared to Pre-COVID-19 (p< 0.01). The greatest change was a delay in weekday waketime of 2.9+/-0.9h (p<0.001). Social jetlag during COVID-19 was reduced by 1/3 compared to Pre- COVID-19 (p=0.02). Average 24h lux levels were 2.5x higher during the COVID-19 week compared to Pre- COVID-19 (p=0.008). Change in average lux and timing of light were not significantly associated with change in sleep duration or timing. Conclusion(s): An unintended effect of the switch to online learning may have been affording adolescents the opportunity to obtain longer and more regular sleep. Understanding the impact of these changed sleep behaviors on daytime functioning, academic performance, and health outcomes is particularly urgent as schools plan for the remainder of the academic year and eventual return to in-person learning.