From the CDC report.

Five out of every six middle schools and high schools nationwide start classes earlier than 8:30 a.m., making it difficult for teens to get the sleep they need to be healthy, according to a report published Thursday by the Centers for Disease Control and Prevention.

The American Academy of Pediatrics recommends that schools start later than 8:30 a.m. to help teens avoid becoming chronically sleep-deprived and exhausted. Adolescents need between 8.5 hours and 9.5 hours of sleep each night, but their natural sleep rhythms make it hard for them to fall asleep before 11 p.m., according to the academy.

Research has shown that teens who get too little sleep are more likely to be overweight or depressed, and they are more likely to perform poorly in school and to experiment with tobacco, alcohol and other drugs.

The CDC, in its new report, calls insufficient sleep among the nation’s teenagers a “substantial public health concern,” and says that while parents can help by teaching their children good sleep hygiene (no cell phones in the bedroom, for example), it is important for schools to do their part by ensuring that class doesn’t start too early.

“Getting enough sleep is important for students’ health, safety, and academic performance,” said Anne Wheaton, a CDC epidemiologist and the report’s lead author. “Early school start times, however, are preventing many adolescents from getting the sleep they need.”

Researchers reviewed start-times for the 2011-2012 school year at a sample of the nation’s nearly 40,000 middle schools and high schools. Their findings illuminate the fact that many young people begin their days very early. The average start time nationwide was 8:03 a.m., but there were wide variations across the country:

  • The state with the latest average start time was Alaska, at 8:33 a.m. The earliest was Louisiana at 7:40 a.m. (Louisiana also had the highest proportion of schools starting before 7:30 a.m., at 30 percent.)
  • No schools in Hawaii, Mississippi, and Wyoming started at 8:30 a.m. or later, while more than three-quarters of schools in Alaska and North Dakota started at 8:30 a.m. or later.
  • In 42 states, more than three-quarters of schools started before 8:30 a.m.

Two-thirds of teens say they get less than eight hours of sleep per night, according to the CDC’s 2013 Youth Risk Behavior Surveillance.

Research on the importance of sleep has pushed parents in many communities to press for later school start times. But they often face resistance, not only because changing start times (and therefore school bus schedules) can create logistical difficulties and expense, but also because of concerns that starting later means less time in the afternoon for teens to work a part-time job or participate in extracurricular activities.

The CDC’s new report establishes a baseline that will allow researchers to see how many schools change their start times following the 2014 recommendation for schools to start class after 8:30 a.m.

[Fairfax County high schools push back start times.]

Fairfax County, Va., one of the nation’s largest school systems, decided to push its high-school start times back for this coming school year, delaying high school starts to between 8 a.m. and 8:10 a.m., in a near-unanimous school board vote. Board members cited health benefits to teens as a leading factor in the change, which had been debated for many years. In a compromise, Montgomery County, Md., the state’s largest school district, pushed high school start times 20 minutes later — to 7:45 a.m. — after heated debate on the subject. Advocates had wanted later start times, pushing for first bells at 8:30 a.m., also citing the health benefits.