Impact of School Start Time Delays and Learning Modality on Sleep Timing and Duration During COVID-19.

OBJECTIVES: To assess the impact of a school start time (SST) delay on adolescent sleep health during the COVID-19 pandemic, and whether there were differences by learning modality. METHODS: Data were collected from a longitudinal study evaluating sleep, education, and health among high school students in Georgia in 2020. Paired t-tests and multivariable linear regression analyses were conducted to examine changes in sleep duration and timing among 9th grade students (n = 134) and their association with the learning modality (remote vs. in-person learner). RESULTS: Students' school day wake times were 1.5 hours later, school night sleep duration was 1.2 hours longer, and social jetlag was 0.9 hours shorter after the school start time delay (all P < .05). The learning modality was a significant predictor of changes in sleep timing but was not associated with changes in sleep duration. CONCLUSIONS: Delayed school start time was associated with positive changes in adolescent sleep health during the COVID-19 pandemic. Sleep timing was affected by the learning modality, however in-person and virtual students had similar gains in sleep duration. Learning modality may be more beneficial for adolescents with early school start times to promote healthier sleep habits.

The Association of Sleep Duration with Grade Point Averages and Absences Among 9th Graders in Georgia, USA.

This study aimed to examine the association between sleep measures (self-reported sleep duration and weekend catch-up sleep) and grade point average (GPA) and absences among 9th grade students from two racially and economically diverse high schools in a semi-rural county of north-central Georgia. Linear and Poisson regression models estimated the association between sleep measures and GPA and absences (separately), respectively. Analyses adjusted for gender, race/ethnicity, free/reduced-price school lunch status, and parental education. Sleep duration was significantly associated with both GPA and absences, such that for every one additional hour of sleep, GPA increased by 0.8 percentage points (b=0.8, 95% CI:0.1,1.5) while the number of absences was lower by 6% (b=-0.05; OR=0.94, 95% CI:0.91,0.98). Weekend catch-up sleep was also significantly and positively associated with absences (b=0.04; OR=1.04, 95% CI; 1.02, 1.07). Increasing sleep may be a strategy to improve GPA and reduce absences among teenagers. Future research should identify effective measures to lengthen sleep.

The longitudinal association between objectively-measured school-day physical activity and academic achievement in US elementary school students.

BACKGROUND: It is recommended that school-aged children accrue 30 minutes of daily moderate-to-vigorous physical activity (MVPA) in school. Current literature is inconclusive about the long-term associations between school-based physical activity and academic achievement. In this study, we use a large sample and longitudinal design to rigorously evaluate whether school-day MVPA is associated with academic achievement. METHODS: In a diverse suburban public school district, 4936 Grade 4 students were recruited in 40 elementary schools. Students wore accelerometers to measure school-day MVPA for 15 days across three semesters. Academic performance data was collected across Grade 3 fall to Grade 5 spring, including teacher-assigned grades and standardized test scores. Multilevel modeling was conducted controlling for student demographics and school characteristics. RESULTS: Cross-sectional analyses found small negative associations in Grade 4. Grade 4 full-year mean daily school-day MVPA had ß = --0.066, ß = --0.063, ß = --0.066, and ß = --0.058 associations (p <  0.001) with Grade 4 math, reading, spelling, and writing grades respectively, and Grade 4 full-year mean daily school-day MVPA had ß = --0.206 and ß = --0.283 (p <  0.001) associations with Grade 4 math and English Language Arts (ELA) standardized test scores respectively out of approximately 500 points. Longitudinal analyses found no significant associations between Grade 4 full-year mean daily school-day MVPA and Grade 5 Fall course grades. Results also indicated small negative associations for students attaining 30+ minutes of daily school-day MVPA compared to those attaining less than 15 minutes, but only in Grade 4 Fall cross-sectional analyses where teacher-assigned reading, spelling, and writing grades were - 1.666, - 1.638, and - 1.993 points lower respectively (p <  0.001). CONCLUSION: The cross-sectional findings, while statistically significant in a negative direction, have a negligible association when translated practically. For example, even if students attained twice the recommended amount of school-day MVPA - which would constitute an approximately 300% increase from current levels - results suggest that grades would only decrease by 2 points on a 100-point scale. Furthermore, longitudinal analyses suggest school-day MVPA does not have a predictive association with course grades or standardized test scores. Findings suggest school-based MVPA implemented in accordance with recommendations does not meaningfully detract from academic progress. TRIAL REGISTRATION: ClinicalTrials.gov , NCT03765047. Registered 05 December 2018 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03765047.

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.