Adolescent Sleep and School Start Times During Early COVID-19 School Closures Open Access

Weingart, Rachel (Spring 2021)

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Background: Adolescent sleep health is a national priority, as less than 30% of teenagers report sufficient nightly sleep duration. Insufficient sleep is associated with poor physical health, mental health, and academic performance in this age group. Early school start times are a major environmental influence on adolescent sleep duration and timing. The arrival of COVID-19 in the United States caused a widespread transition to remote learning and afforded a unique opportunity to study adolescent sleep without the impact of external factors such as early school start times, bus pickups, and morning extracurricular activities.

Objective: This study investigates adolescent sleep and changes in sleep patterns during COVID-19-related school closures in the United States. This study also assesses the relationship between school start time during COVID-19 and adolescent sleep behaviors and examines other predictors of adolescent sleep behaviors during school closures.

Participants and Setting: An online cross-sectional survey instrument adapted from the School Sleep Habits Survey was distributed through local Start School Later chapters and administered to middle and high school students from May 7 to June 30, 2020. The final analytic sample was restricted to 590 participants in grades 6-12 who were attending remote classes in 35 U.S. states.

Methods: This study quantitatively examined descriptive statistics for seven sleep behaviors, including during school closures (weekday wake time, weeknight bedtime, weeknight sleep duration, weeknight time in bed, daytime sleepiness), and changes from pre- to post-school closures (in weekday wake time and sleep duration). Multivariate linear and logistic regression analyses assessed the relationship between selected predictors (gender, race/ethnicity, class start time, parent-set bedtime, trouble sleeping, and caffeine use) and sleep outcomes, stratified by grade category (6-8th, 9-10th, and 11-12th).

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 bedtimes and wake times, accompanied by spending less time in bed and less time sleeping. High school students also reported a greater delay in wake time (2.9 hours) than did middle schoolers (2.1 hrs). High school students with later class start times went to bed later (β11-12th=1.0 hrs), but also woke up later (β9-10th=1.4 hrs, β11-12th=1.9 hrs), slept longer (β9-10th=1.0 hrs, β11-12th=0.9 hrs), and spent more time in bed (β9-10th=1.1 hrs, β11-12th=0.9 hrs) compared to those starting class earlier. When comparing intra-individual sleep pre- and post-school closures, later class start times resulted in greater delays in wake time (β9-10th=1.2 hrs, β11-12th=1.5 hrs) and greater odds of increased sleep duration among high schoolers (OR9-10th=5.6). Later class start times were also significantly associated with decreased odds of daytime sleepiness (OR9-10th=0.3) and with a decreased proportion of participants reporting sleepiness during online class (p=0.0004). In addition, parent-set bedtimes were associated with earlier bedtimes in all grade categories (β6-8th=-1.5 hrs, β9-10th=-1.2 hrs, β11-12th=-1.2 hrs), as well as with other sleep outcomes among middle schoolers.

Conclusions: As a consequence of COVID-19-related school closures, more middle and high school students achieved recommended amounts of sleep, primarily by waking up later in the morning. Students with earlier synchronous class start times slept less and had smaller changes in their weekday wake times during COVID-19 school closures, confirming previous findings that school start time is a strong external influence on 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. Findings can inform policies on school start timing as well as sleep health education advocacy for parents and students, especially in those school districts that have not yet implemented later school start times.

Table of Contents


Problem Statement

Theoretical Framework

Purpose Statement

Research Questions

Significance Statement


Adolescent Sleep Health

Consequences of Poor Sleep in Adolescents

The Social-Ecological Model for Understanding Causes of Poor Sleep in Adolescents

School Start Times and Adolescent Sleep Health

Adolescent Sleep During COVID-19

Summary of Current Problem and Study Relevance














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