Mounting medical evidence suggests that young people need to sleep later in the morning to prevent serious health issues, reports The Intelligencer.

As he listened to public health advocates discuss teenagers’ need for sleep and the importance of schools beginning classes later in the day, Charles Lambert, Council Rock’s director of special services, asked himself “How do I not know this stuff?”

Lambert attended a national conference in Washington, D.C., on “Adolescent Sleep, Health, and School Start Times,” where he heard several medical authorities call for the school day to begin after 8:30 a.m. to accommodate changes in the sleep patterns of adolescents.