Furthermore, the later start time had no effect on the number of hours students spent doing homework, playing sports or participating in extracurricular activities. The study, led by psychologist and sleep expert Julie Boergers, Ph.D., is published in the Journal of Developmental & Behavioral Pediatrics.
It is well-known that sleep deprivation is common among teens, 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.”
For the study, boarding school students attending an independent high school were given a survey 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 getting eight or more hours of sleep on a school night jumping from 18 percent to 44 percent.
The findings showed that younger students and those sleeping less at the start of the study received the most benefits from the schedule change. And once the later start time went back to normal during the spring term, teens reverted back to their original sleep duration.
During the later starting time, daytime sleepiness, depression and caffeine use were all significantly reduced, but there was no effect on the number of hours students spent doing homework, playing sports or participating in extracurricular activities.
Boergers, who is also co-director of the Paediatric Sleep Disorders Clinic at Hasbro Children’s Hospital in Providence, R.I., believes 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.”