High School Students With A Delayed School Start Time Sleep Longer, Report Less Daytime Sleepiness

Wednesday, June 11th, 2008

I have never understood why high school should start hours earlier than an ordinary work day. I certainly never liked it. Now scientists have found that high school students with a delayed school start time sleep longer and report less daytime sleepiness:

The study, authored by Zaw W. Htwe, MD, of Norwalk Hospital’s Sleep Disorders Center in Norwalk, Conn., focused on 259 high school students who completed the condensed School Sleep Habits Questionnaire. Prior to the delay, students reported sleeping a mean of 422 minutes (7.03 hours) per school night, with a mean bed-time of 10:52 p.m. and a mean wake-up time as 6:12 a.m.

According to the results, after a 40-minute delay in the school start time from 7:35 a.m. to 8:15 a.m., students slept significantly longer on school nights. Total sleep time on school nights increased 33 minutes, which was due mainly to a later rise time. These changes were consistent across all age groups. Students’ bedtime on school nights was marginally later, and weekend night sleep time decreased slightly. More students reported “no problem” with sleepiness after the schedule change.

“Following a 40-minute delay in start time, the students utilized 83 percent of the extra time for sleep. This increase in sleep time came as a result of being able to ‘sleep in’ to 6:53 a.m., with little delay in their reported school night bedtime. This study demonstrates that students given the opportunity to sleep longer, will, rather than extend their wake activities on school nights,” said Mary B. O’Malley, MD, PhD, corresponding author of the study.

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