Teens increasingly sleep deprived

The study is the first comprehensive evaluation of recent sleep trends by age and time period for U.S. adolescents.

Students in the 8th, 10th and 12th grades of a nationally representative survey of more than 270,000 adolescents from 1991 to 2012 reported how often they get seven or more hours of sleep.

The proportion of adolescents who regularly got seven hours of sleep was defined as a frequency of every day or almost every day versus sometimes, rarely, or never. The survey did not control for weekday versus weekend wake-up and sleep times.

Racial/ethnic minorities and those whose parents had little formal education said they were less likely to regularly get seven or more hours of sleep, yet they were more likely to report getting adequate sleep, suggesting a mismatch between actual sleep and perceptions of adequate sleep.

"This finding implies that minority and low socioeconomic status adolescents are less accurately judging the adequacy of the sleep they are getting," said Katherine W. Keyes, PhD, assistant professor of Epidemiology at the Mailman School of Public Health and lead author.

The largest decrease in the percentage getting seven hours of sleep per night was 15-year-olds, a particularly concerning trend for a significant portion of U.S. students at this important juncture in development. Among this age group, 72 percent reported regularly getting seven-plus hours of sleep per night in 1991; by 2012, in the same age group, 63 percent of adolescents reported regularly receiving seven or more hours of sleep per night. The largest declines for all adolescents occurred between 1991 and 1995 and 1996 and 2000. The disparity according to race has increased in more recent time periods.

Seven hours per night is two hours less than the nine hours recommended by the National Sleep Foundation. Inadequate sleep is associated with a wide range of health problems including mental health issues, academic problems, substance abuse, and weight gain.

"Although the underlying reasons for the decreases in hours of sleep are unknown, there has been speculation that increased Internet and social media use and pressures due to the heightened competitiveness of the college admissions process are adding to the problem," noted Dr. Keyes. "Declines in self-reported adolescent sleep across the last 20 years are concerning and suggest that there is potentially a significant public health concern that warrants health education and literacy approaches."