Adequate amounts of sleep help the brain absorb learning. Too little sleep has been linked to obesity, diabetes and other ills. (ISTOCKPHOTO)
Sleep habits
Teens who stay up late may face struggles years later

THE QUESTION Many teenagers stay up quite late. Does this have any long-term effects?

THIS STUDY analyzed data on 2,700 people, 13 to 18 years old at the start of the study. About a third of them went to bed after 11:30 p.m. on school nights and after 1:30 a.m. during the summer. Six to eight years later, those with the late-night bedtimes during the school year had not done as well academically and had lower grade-point averages at the end of high school than those who had gone to bed earlier. Those who had stayed up late during the school year or during the summer — especially when they were 14 to 16 years old — also reported more emotional distress (including sadness, irritability and depression) when they were 18 to 26 years old than their earlier-to-bed peers. Summer-only late nights did not affect academic performance.

WHO MAY BE AFFECTED? Middle school and high school students, who, health experts say, need about nine hours of sleep a night. For people of all ages, adequate amounts of sleep not only help the body feel rested and energized the next day but also help the brain absorb learning and form memories. Too little sleep, on the other hand, has been linked to various health conditions, including obesity, diabetes, cardiovascular disease and mood disorders.

CAVEATS Sleep data came from the youths’ responses on questionnaires. Factors not accounted for in the study may have affected academic performance.

FIND THIS STUDY Nov. 11 online issue of the Journal of Adolescent Health.

LEARN MORE ABOUT sleep at (Search for “sleep overview,” click on a link and then look for “condition information.”) Learn about teens and sleep at (Click “For Teens” tab.)

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.