December 16, 2008

Later teen school day, fewer car accidents

Having teens start school one hour later, allowing students to sleep longer, resulted in a drop in teen auto accidents, U.S. researchers said.

Senior author Dr. Barbara Phillips, director of the University of Kentucky Healthcare Good Samaritan Sleep Center in Lexington, said that when school started an hour later students reported sleeping from 12 minutes to 30 minutes more per night.

The percentage of students who got at least eight hours of sleep per weeknight increased significantly from 35.7 percent to 50 percent while students who got at least nine hours of sleep also increased from 6.3 percent to 10.8 percent.

The average amount of additional weekend sleep, or catch-up sleep, decreased from 1.9 hours to 1.1 hours and daytime sleepiness decreased, the study said.

The study, published in the Journal of Clinical Sleep Medicine, found the average crash rate for teen drivers in the study's county in the two years after the change in school start time dropped 16.5 percent compared to the two years prior to the change while teen crash rates for the rest of the state increased 7.8 percent over the same time period.

It is surprising that high schools continue to set their start times early, which impairs learning, attendance and driving safety of the students, Phillips said in a statement.