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Lack of Sleep Among Teens Makes Them Overweight, Unhealthy, CDC Finds


The CDC report underscores last year's recommendation from the American Academy of Pediatrics. American teenagers are not getting enough sleep because in most places the school days start too early.

Teenagers who do not get enough sleep are more likely to be overweight, depressed, use drugs or alcohol, perform poorly in school, and suffer from a lack of exercise, according to a report from the CDC that called for American schools to embrace recommendations to roll back the start of the school day.

The study released yesterday, conducted jointly by CDC and the US Department of Education, examined data from the 2011-2012 Schools and Staffing Survey, which covered an estimated 39,700 public middle, high, and combined schools. The average start time was 8:03 a.m. However, overall, only 17.7% of the schools started the day at 8:30 a.m. or later.

School start times vary greatly by state. Starting school at 8:30 a.m. or later matters, because it allows teenagers to sleep 8.5 to 9.5 hours per night, which is the amount recommended in 2014 by the American Academy of Pediatrics. The National Sleep Foundation recommends 8-10 hours for this age group.

Changes that occur during puberty make it difficult for teenagers to fall asleep earlier than 11 p.m. at night; thus, even a 30-minute earlier school start time can mean increased sleepiness during the day. Troubles with concentration, behavior, lateness and absenteeism often occur. In recent years, the problem with getting teens to go to sleep has been compounded by the rise of smartphones, computers, tablets, and video games.

The migration to earlier start times for older students has occurred as school districts sought to accommodate after-school sports schedules, student jobs, and, especially, the desire the limit the number of buses and drivers. Districts typically deploy bus drivers on an early route to pick up older children, then send them back through communities to pick up younger children to transport to elementary schools.

The connection between adequate sleep and health and academic performance is “of substantial public health concern,” the report said. It notes that the goals of Healthy People 2020 call for increasing the share of high school students who get at least 8 hours of sleep each night; however, the share has remained stuck at 31% since 2007, the first year the National Youth Risk Behavior Survey included a question about sleep.

Pushing back the school day for high school students would require adjusting all of these elements, and would be met with resistance, which the CDC notes in its study. Despite these barriers, “many school systems have successfully overcome barriers to delay start times,” the report said.


Wheaton AG, Ferro GA, Croft JB. School start times for middle school and high school students--United States, 2011-2012 school year. MMWR 2015;64(30): 809-813.

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