Adolescent sleep duration and timing during early COVID-19 school closures.

Objectives: To investigate adolescent sleep parameters and predictors during COVID-19-related school closures.

Methods: Original data were analyzed from a cross-sectional online survey of 590 teens in grades 6-12 attending school remotely in 35 US states, in May/June 2020.

Results: Students reported waking up 2.1-2.9 hours later during school closures and averaged 7.9-8.7 hours of sleep and 8.6-9.5 hours in bed on school nights. Compared to middle schoolers, high school students had later bed and wake times, accompanied by spending less time in bed and less time sleeping. The delay in wake time after school closures was also longer for high school students than for middle schoolers. Students with later class start times went to bed later, but also woke up later, slept longer, and spent more time in bed. When comparing intraindividual sleep before and after school closures, later class start times resulted in greater delays in wake time and greater odds of increased sleep duration. In addition, parent-set bedtimes were associated with earlier bedtimes and longer sleep duration during school closures.

Conclusions: As a result of COVID-19-related school closures and remote instruction, more middle and high school students achieved recommended amounts of sleep, primarily by waking up later in the morning. This study supports previous evidence that morning start schedule affects adolescent sleep behaviors. The implications of this study extend beyond COVID-19 school closures; adolescent sleep health improves with later school start times and fewer scheduled morning activities.