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OBJECTIVE: To determine whether shorter school-night sleep duration, greater daytime sleepiness, and greater eveningness chronotype were associated with lower self-regulation among adolescents. METHODS: An online survey of 7th- to 12th-grade students in 19 schools in Fairfax County, Virginia Public Schools was conducted in 2015. Self-regulation was measured with the Behavior Rating Inventory of Executive Function, 2nd edition, Screening Self-Report Form. Sleep measures included school night-sleep duration (hours between usual bedtime and wake time), daytime sleepiness (Sleepiness Scale in the Sleep Habits Survey, tertiles), and chronotype (Morningness--Eveningness Scale for Children, continuous score and tertiles). Sociodemographic factors and mental health conditions were analyzed as potential confounders. RESULTS: Among 2017 students surveyed, the mean age was 15.0 years (range, 12.1-18.9 years), and 21.7% slept <7 hours on school nights. In regression models adjusted for confounders, there was a significant independent association between self-regulation and both chronotype (P < .001) and daytime sleepiness (P < .001) but not sleep duration (P = .80). Compared with those in the lowest tertile of daytime sleepiness, those in the highest tertile had lower (0.59 SD units; 95% confidence interval, 0.48-0.71) self-regulation, as did those in the eveningness tertile of chronotype compared with those in the morningness tertile (0.35 SD units lower; 95% confidence interval, 0.24-0.46). CONCLUSIONS: Among adolescents, greater daytime sleepiness and greater eveningness chronotype were independently associated with lower self-regulation, but shorter sleep duration was not. Aspects of sleep other than school-night sleep duration appear to be more strongly associated with self-regulation. [ABSTRACT FROM AUTHOR]

Objective: To determine whether school start time changes impact adolescents' mood, self-regulation, safety, and health., Methods: In September 2015, two school start time changes were implemented in Fairfax County (VA) Public Schools: a 50-minute delay (to 8:10 am) for high schools and secondary schools and a 30-minute advance (to 7:30 am) for middle schools. We conducted cross-sectional surveys of students' sleep, mood, self-regulation, health, and safety before (2017 students) and after (1180 students) these changes., Results: Adjusted for confounders, a 50-minute delay was associated with a decreased prevalence of low mood (-4.7%; 95% confidence interval [CI]: -8.2%, -1.2%), drowsy driving, (-8.4%; 95% CI: -15.9%, -0.9%), and skipping breakfast (-4.2%; 95% CI: -8.1%, -0.2%) but no other significant changes. There were no significant changes associated with a 30-minute advance., Conclusions: A 50-minute delay in school start time in high schools and secondary schools was associated with a decreased prevalence of low mood, drowsy driving, and skipping breakfast. A 30-minute advance in start time in middle schools was not associated with any appreciable changes., (Copyright © 2019 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.)