Starting the high school day later would be better for adolescents' health, according to a report that Fairfax County school leaders are expected to discuss Tuesday.

A later start to the school day for teens would be "more reflective of adolescent biorhythms," according to the report by Fairfax County Public Schools' School Health Advisory Committee.

A growing body of research shows that adolescents' biology causes them to fall asleep later than adults, said committee Chairwoman Marie Reinsdorf. However, most high schools in Fairfax start at 7:20 a.m., forcing students to fight their natural rhythm.

The resulting sleep deprivation can lead to poor academic performance and a tendency to make impulsive decisions, said Therese Tuley, chairwoman of the local advocacy organization Start Later for Excellence in Education Proposal, or SLEEP.

The advisory committee has endorsed later school start times since 2005, and the county School Board passed a resolution in April 2012 favoring a later school day.

But if all goes according to plan, the later school day could finally become reality in a little more than a year.

The problem has been finding a practical solution that everyone likes, said Fairfax County School Board member Jane Strauss, who represents Dranesville.

Buying enough school buses so that neither elementary nor middle school schedules would need to change is not financially feasible. Other options -- pushing start times back across all grade levels or starting elementary schools at 7:20 a.m. so that high schools can start after 8 -- create logistical problems for parents who need to get to work or who can't leave work early enough to meet young kids at the bus, as well as for students who have extracurricular activities or jobs after school.

"The other problem that we have is just congestion and traffic. I know in some parts of the county, even if we changed high school start times by 30 minutes [or] 35 minutes, we couldn't change the bus pick-ups [and still get students to school on time]," Strauss said.

Fairfax County Public Schools contracted earlier this year with Children's National Medical Center to study the issue and come up with possible solutions. The findings are expected in the middle of the coming school year, so that -- if the School Board and the community like the solutions -- high schools could have later school days as early as the 2014-2015 school year, said Assistant Superintendent Kim Dockery.

Fairfax is the latest school system to join the movement to implement later start times. Parents in Montgomery County also have been fighting for later start times, and Arlington County already has them.

"I just hope for thousands or tens of thousands of students, that they have something that is more in keeping with their health," Reinsdorf said.