High school in the United States starts way too early. Given teenagers' sleep patterns, the ideal school start time could be as late as 11:30 am— when many high school students have already finished half a school day and are eating lunch.

Related The case for letting high school students sleep in



Researchers from Harvard and Oxford wrote about this new finding in a recent article in the journal Learning, Media, and Technology. In the article, Paul Kelley, Steven W. Lockley, Russell G. Foster, and Jonathan Kelley argue that given when kids and teenagers are biologically conditioned to wake up, 10-year-olds should start school at 8 am, 16-year-olds should start between 10 and 10:30 am, and 18-year-olds should start between 11 and 11:30 am.

There's been lots of research done on sleep and performance in school — but this article argues that school should start even later than most proposals for a later start time call for.

Teens aren't lazy — adults need to adjust

This isn't laziness — sleep patterns are a biological necessity. Reviewing evidence from studies around the world, the researchers argue that starting school later would help students learn more, perform better on tests, and even be less grumpy.

Here's a sample of what they found across the US:

In North Carolina, eighth-grade students who started class an hour later than their peers in the same district had higher test scores. The later start time seemed especially helpful for low-scoring students, and the effects persisted into high school.

When the Minneapolis Public Schools moved their start time from 7:15 am to 8:40 am, students liked the change and reported that "attendance, achievement, behavior, and mood improved." Parents were positive, too: 92 percent said they liked the shift, and parents reported that their kids were easier to live with when they weren't getting up so early.

At the US Air Force Academy, where students were randomly assigned to classes with earlier and later start times, students who started earlier performed worse all day long on those days.

But almost no school districts start after 9 am

Policymakers and pediatricians have been saying school should start later for a while now. The American Academy of Pediatricians recommends a start time of 8:30 am. The researchers in the new journal article go further, arguing that 8:30 am is still too early for teenagers.

But vast majority of school districts in the US start much earlier. The average school start time nationwide is 8:03 am, when many teenagers should probably still be in bed:

The researchers argue that this is partly cultural, and that getting up early is still seen as a virtue to be cultivated rather than something unnatural and unnecessarily challenging. That's wrong, they write: "A common belief is that adolescents are tired, irritable and uncooperative because they choose to stay up too late, or are difficult to wake in the morning because they are lazy. Educators tend to think that adolescents learn best in the morning and if they simply went to sleep earlier, it would improve their concentration. … The truth is that adults need to be educated."