Later school start times improve sleep and daytime functioning in adolescents

The article, titled "Later School Start Time is Associated with Improved Sleep and Daytime Functioning in Adolescents," appears in the current issue of the Journal of Developmental & Behavioral Pediatrics.

"Sleep deprivation is epidemic among adolescents, with potentially serious impacts on mental and physical health, safety and learning. Early high school start times contribute to this problem," said Boergers. "Most teenagers undergo a biological shift to a later sleep-wake cycle, which can make early school start times particularly challenging. In this study, we looked at whether a relatively modest, temporary delay in school start time would change students' sleep patterns, sleepiness, mood and caffeine use."

Boergers' team administered the School Sleep Habits Survey to boarding students attending an independent high school both before and after their school start time was experimentally delayed from 8 to 8:25 a.m. during the winter term.

The delay in school start time was associated with a significant (29 minute) increase in sleep duration on school nights, with the percentage of students receiving eight or more hours of sleep on a school night jumping from 18 to 44 percent. The research found that younger students and those sleeping less at the start of the study were most likely to benefit from the schedule change. And once the earlier start time was reinstituted during the spring term, teens reverted back to their original sleep levels.

Daytime sleepiness, depressed mood and caffeine use were all significantly reduced after the delay in school start time. The later school start time had no effect on the number of hours students spent doing homework, playing sports or engaging in extracurricular activities.

Boergers, who is also co-director of the Pediatric Sleep Disorders Clinic at Hasbro Children's Hospital, said that these findings have important implications for public policy. "The results of this study add to a growing body of research demonstrating important health benefits of later school start times for adolescents," she said. "If we more closely align school schedules with adolescents' circadian rhythms and sleep needs, we will have students who are more alert, happier, better prepared to learn, and aren't dependent on caffeine and energy drinks just to stay awake in class."