High school students in Manassas will get an extra 50 minutes of sleep next year thanks to a decision last week to move their school starting time later than that of fifth- through eighth-graders.

Studies have shown that even modest adjustments to make school bells later lead to improved health, behavior and attendance among teenagers, whose body clocks are naturally set to go to sleep later and snooze until well past sunrise. In several school districts across the country, high school start times have been moved later in the morning. Fairfax County is currently considering such a change.

“There’s research that shows that a later start time, a later sleep pattern for teenagers, is beneficial in their education,” said Tim Demeria, chairman of the school board. “It helps with depression. It helps with education. It helps with sports. It helps with driving ability: There’s research that shows that districts that have gone to later start times have lesser accidents in the morning.”

Demeria said that the idea of moving school start times later had been on the table for years in Manassas, but was pushed to the forefront by plans to build a new elementary and intermediate school close to the location of the district’s only high school. The new school, scheduled to open in fall 2016, required that the district change the existing bus schedule at least slightly.

The board asked for public comments on four proposed schedules, and settled on one that moves Osbourn High School’s start time from 7:20 a.m. to 8:10 a.m., starting in fall 2014.

Metz Middle School, which serves seventh- and eighth -graders in the district, will move its start 10 minutes earlier, from 7:30 to 7:20. The fifth- and sixth-graders in the district, who attend Mayfield Intermediate School, will see the largest change in their schedule, moving all the way back from their current 8:50 bell to 7:35. Their school day will be five minutes shorter, ending at 2:40 p.m. rather than 4 p.m.

The district’s five elementary schools will also move to later start times. Dean, Haydon and Round elementaries will start 15 minutes later than before, at 8:35. Baldwin and Weems will jump from their current 7:55 start to 9:05, meaning their day will also end the latest, at 4:15.

The high school will end at 3:15, an hour later than it used to, and some parents and students raised concerns that the later dismissal will cut down on time students can spend on sports, extracurricular activities, after-school jobs and babysitting for younger siblings.

“That was important to us. But more so, what works for the Manassas City Schools family is more important than any individual family,” Demeria said. “A lot of people didn’t like the idea of what we chose. They didn’t want change, or they wanted the high school to go last, or they wanted the high school to go first. It was all over the board, and they were all very good arguments.”

The board narrowly voted for the new schedule, 4 to 3. The three members who voted against it did not respond to requests for comment Tuesday afternoon.

Demeria said he expects that other school districts in the region, including Prince William County, will soon consider changing their start times as the evidence about teenagers’ sleep needs grows.

“This is a big deal,” he said.