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MONDAY, Jan. 20, 2014 (HealthDay News) -- Delaying the morning school bell might help teens avoid sleep deprivation, according to a new study. Later school start times appear to improve teens' sleep and reduce their daytime sleepiness.
For the study, investigators assessed boarding students at an independent high school before and after their school start time was changed from 8 a.m. to 8:25 a.m. during the winter term.
The later start time was associated with a 29-minute increase in the students' amount of sleep on school nights, and the proportion who got eight or more hours of sleep on a school night increased from 18 percent to 44 percent, the study found.
Younger students and those who slept less at the start of the study were most likely to benefit from the later school start time, according to the results published in the January issue of the Journal of Developmental & Behavioral Pediatrics.
The researchers also found that the later start time also led to significant reductions in students' daytime sleepiness, depressed mood and caffeine use. However, the later start time had no effect on the number of hours that students spent on homework, playing sports or doing extracurricular activities.
When the earlier school start time was put back in place during the spring term, the students went back to their original sleep levels, the authors noted.
"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," study leader Julie Boergers, a psychologist and sleep expert from the Bradley Hasbro Children's Research Center in Providence, R.I., said in a Lifespan health system news release.
These findings "add to a growing body of research demonstrating important health benefits of later school start times for adolescents," she added.
"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," Boergers said.
The National Sleep Foundation has more about teens and sleep.