Sleeping in may help teens' school performance

Parents of teens will recognize the situation: your child stays up until all hours, refusing to go to bed, then sleeps in till noon come the weekend. Meantime, he or she falls asleep in class, claims to be too tired to do homework, and seems to get grouchier each day.

It may be infuriating, but teens are actually responding to a real shift in their body clock that happens around the same time as puberty. The internal mechanisms that govern when they wake and when they sleep shift a couple of hours compared to younger children, so teens actually find it very hard to sleep before around 11 pm. However, they still need the same amount of sleep – around 9 hours – which is hard to get, if they have to get up before 7 am to be at school on time. The results are tired, grouchy kids who don't learn as well as they might.

An experiment at an independent school in Rhode Island shows that the answer might be simply going with nature, by allowing kids to sleep in later on school days. Shifting the start of the school day just half an hour – from 8 am to 8.30 am – had a startling impact on everything from students missing class, to their self-reports of drowsiness in class, and even their mood.

The study found that, after 3 months of the new timetable, teens were getting around 45 minutes extra sleep each night. They were happier, more alert and more likely to feel motivated to take part in extra activities such as sports or clubs.

Many of the students in the study were boarders at the school, so the results may be more impressive if they'd have been in a public day school, where the school has less control over lights-out and other activities such as after-school jobs.

But it's a striking example of how a small shift can have big results. Is it time for all schools with early start times to consider whether their timetable is getting the best from their students?

What you need to know. Getting enough sleep has a big impact on adolescents' concentration, mood, and school performance. You may not be able to influence your teen's school start time, but you can help them get a good night's sleep through these measures:

• Keep electronic devices like cell phones and laptops out of the bedroom
• Ensure bedrooms are dark, quiet, and kept cool, so they're comfortable for sleep
• Avoid caffeinated beverages like cola, coffee, or chocolate before bed.

—Anna Sayburn, patient editor, BMJ Group

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