A study comparing two similar cities in Virginia found that teens whose high schools started earlier in the day were more likely to have had a car crash.
When schools start the day could have a lot to do with how well teenagers drive. A new study found that earlier high school start times are associated with higher teen car crash rates.
Researchers compared two neighboring cities in Virginia with similar racial and income demographics: Virginia Beach, where the high school day began at 7:20 a.m., and Chesapeake, where classes began 80 minutes later. Using 2008 data from the Virginia Department of Motor Vehicles, researchers found that the car crash rate for 16- to 18-year-olds was about 41 percent higher in Virginia Beach.
Though the study isn't proof, researchers figure the difference may be due to sleep deprivation and a disruption of teens' internal clocks.
Teens need about nine hours of sleep each night, according to the Mayo Clinic. And how many really do?
"My thought would be in Virginia Beach, probably the students are getting less sleep because it looks like high school start times can be a major determinate of when these guys and gals get up and how much sleep they get," the study's lead author Dr. Robert Vorona, an associate professor at Eastern Virginia Medical School in Norfolk, Va., tells Shots.
One of the next steps, Vorona says, is to investigate how much sleep students in these cities actually get.
While there's a mounting body of evidence emphasizing the importance of a good night's sleep, Vorona says there's not a great deal of data available that looks at the potential impact of insufficient sleep in teenagers and car crashes.
Vorona's findings, however, are in line with a 2008 study published in the Journal of Clinical Sleep Medicine. In that study, researchers found that after a county-wide school district pushed the school start time back by one hour, teen car crashes dropped by 16.5 percent. Students in this district also got more sleep.
Some high schools across the country already have begun pushing back their starting times. However, Vorona says there is still work that needs to be done in order to establish a causal relationship.
"My bias is, based on the literature I've read, that a later high school start time would be helpful to our teenagers," Vorona says. "But I think before we are dogmatic and telling school administrators and parents and teachers that they should make this change that we've got to obtain more data."
The study will be presented Wednesday at the SLEEP 2010 meeting in San Antonio.