A blog article from the New York Times (To Keep Teenagers Alert, Schools Start to Let Them Sleep In) observes a study in which high schools with later start times (say 8am, as opposed to 7:20am) tend to have students that had lower commute accidents, better attendance, and possibly better grades/test scores.
One might ask, if the day starts later, won’t the kids stay up even later? It turns out that physiologically, younger adults have preset programs that induce sleepiness much later in the night. Shifting the start time of school simply matches their obligations to their physiology.
But possibly the most important aspect of this:
Many researchers say that quality sleep directly affects learning because people store new facts during deep-sleep cycles. During the rapid-eye-movement phases, the brain is wildly active, sorting and categorizing the day’s data. The more sleep a teenager gets, the >better the information is absorbed.
So at the end of the day, it’s okay to go to sleep if you’re tired. It’ll help your brain for the next day.