Call for Later School Start Times to Improve Adolescent Sleep Habits

Sleeping prone
Sleeping prone
Only one-third of adolescents get at least 8 hours of sleep on weeknights.

This is one mandate teens are not likely to object to. The CDC is renewing its call for later school start times to make a dent in the sleep deficit seen among many adolescents.

Last year, the American Academy of Pediatrics (AAP) released a policy statement encouraging U.S. middle and high schools to alter school start times in order to allow students to get sufficient sleep in a bid to improve overall health and wellness and academic performance. The AAP recommended a start time no earlier than 8:30 a.m., however the CDC and U.S. Department of Education found that only one in six public middle and high schools adhered to this recommendation.

“Adolescents who do not get enough sleep are more likely to be overweight; not engage in daily physical activity; suffer from depressive symptoms; engage in unhealthy risk behaviors such as drinking, smoking tobacco, and using illicit drugs; and perform poorly in school,” Anne G. Wheaton, PhD, of the CDC, and colleagues wrote in the CDC’s Morbidity and Mortality Weekly Report.

Less than one-third of U.S. high school students get at least 8 hours of sleep on school nights. Currently, the AAP recommends that teens get 8.5 to 9.5 hours of sleep, and the National Sleep Foundation recommends teens get 8 to 10 hours of sleep. At the heart of the problem lie several factors, including biological changes during puberty that shift natural sleep times and poor sleep hygiene, including irregular bedtimes and use of light-emitting electronics in the bedroom.

During the 2011-2012 Schools and Staffing Survey (SASS), the CDC found that of approximately 39,700 middle, high, and combined schools, only 17.7% had school start times at 8:30 a.m. or later, with much state-by-state variation present. The average start time reported was 8:03 a.m., with 42 states reporting that 75-100% of public schools had early start times (before 8:30 a.m.). High schools were least likely to have late start times, while combined schools (23.4%) were most likely to start at 8:30 a.m. or later. No schools in Hawaii, Mississippi, and Wyoming starting at 8:30 a.m. or later, while 76.8% of schools in Alaska and 78.5% of schools in North Dakota had a later start times, 8:31 a.m. and 8:33 a.m., respectively. Louisiana reported the earliest average start time (7.40 a.m.), with 29.9% of its schools starting before 7:30 a.m.

Enforcing such a mandate among school systems isn’t easy since school start times are often determined at the district or individual school level. However, the CDC is encouraging local stakeholders to become more educated on research regarding the impact of insufficient sleep and early school start times on the health and overall wellness of adolescents. The CDC also encourages local supporters to identify groups that may be impacted by the decision to delay start times, such as transportation, and after-school activities, and prepare responses to arguments against early start times.

“Among the possible public health interventions for increasing sufficient sleep among adolescents, delaying school start times has the potential for the greatest population impact by changing the environmental context for students in entire school districts. However, a late school start time does not preclude the need for other interventions that have the potential to improve the sleep of adolescents,” Wheaton and colleagues wrote.

In the meantime, the CDC encourages parents to practice good sleep hygiene by setting regular bed and wake times, including on weekends, limiting nighttime technology and electronic use, and by setting a good example by structuring their own sleep habits.


  1. Wheaton AG et al. MMWR Morb Mortal Wkly Rep. School Start Times for Middle School and High School Students — United States, 2011–12 School Year. 64(30);809-813