Could Later School Start Times Improve Adolescent Health?

Ah, Fall. Yellow school buses swarm streets, often while it’s still dark, a glum reminder that most of the nation’s middle and high schools start too early for most teenagers.

Pubertal delays in the biological clock make it hard for most teenagers to fall asleep before 11 p.m. Most need nine hours of sleep for optimal alertness and health. When schools start early, few get it.

Insufficient sleep boosts teens’ risk of depression, use of alcohol and other substances, suicidal thoughts and attempts, and overall mortality, Wendy Troxel, Ph.D., an adjunct assistant professor of psychiatry and psychology at the University of Pittsburgh School of Medicine, said at the nation’s first national conference on adolescent sleep, health, and school start times earlier this year in Washington, D.C.

Troxel, also a senior behavioral and social scientist at the RAND Corporation, was one of 30 speakers from a broad range of disciplines at the two-day conference that examined how sleep and educational system research could be used to inform public policy on school start times and promote healthy adolescent development. Other speakers included sleep specialists, psychiatrists and other physicians, psychologists, school counselors, other health professionals, students and parents, school superintendents and teachers, school board members, legislators, economists, transportation experts, and community activists.

A 2009 survey of 27,939 middle- and high-school students in Fairfax County, Va., where high schools started at 7:20 a.m., found high school students averaged only 6.5 hours of sleep on school nights, Troxel said, about an hour less than middle schoolers. More than 20 percent of high school students slept less than five hours on average on school nights. Only three percent reported sleeping at least nine hours per night.

Even among students averaging nine hours of sleep per night, 19 percent reported feeling sad and hopeless, 8 percent had considered suicide, and 1.8 percent had attempted suicide. Among students averaging only five hours sleep, a startling half reported having made a suicide attempt, according to an analysis of survey data by Adam Winsler, Ph.D., a professor of applied developmental psychology at George Mason University in Fairfax, and colleagues.

Each hour of missed sleep also increased students’ odds of using tobacco, alcohol, marijuana, and/or illicit/prescription substances. The less sleep students got, the higher their risks overall, Winsler’s team reported in the Journal of Youth and Adolescence in 2015. The corollary also is true, Winsler told Psychiatric News. For each additional hour of sleep, students reported less hopelessness and suicidal ideation, and fewer suicide attempts, regardless of whether researchers compared six hours of sleep to five, or eight hours to seven.

The study’s findings helped spur the Fairfax County School Board to change its middle and high school start times from 7:20 a.m. to 8 a.m. or 8:10 a.m., starting in 2015, said Sandy Evans, school board chair, and co-founder of the advocacy group SLEEP in Fairfax. Fairfax County plans to study the impact of the delay, and to continue to explore the possibility of still later start times.

Aborting sleep after only five or six hours eliminates a significant amount of rapid eye movement (REM) sleep, noted Charles Czeisler, M.D., Ph.D., Baldino Professor of Sleep Medicine at Harvard Medical School. REM sleep, highest in the latter third of the night, is critical for learning, memory consolidation, and emotional processing. Sleepiness increases distractibility, and disrupts the ability to focus, Czeisler said, sometimes triggering a misdiagnosis of attention-deficit/hyperactivity disorder.

Can sleeping two hours later on Saturday and Sunday fully restore sleep-deprived students’ ability to focus? “The answer appears to be ‘No,’” said Dean Beebe, Ph.D., a professor of pediatrics at the University of Cincinnati, and director of Cincinnati Children’s Hospital’s neuropsychology program.

His research and that of others suggests two nights of recovery sleep improves mood in sleep-deprived students, he said, but that may not be enough to return students’ levels of alertness and sustained attention to those obtained when they were fully rested.

Sleepy people often fail to recognize how sleepy they are, Beebe noted, a finding with direct implications for drivers, particularly those who are young and inexperienced.

In weighing school start time delays, parents and educators initially worried that if schools started later, students would stay up later. That fear proved groundless. When school starts later, students typically go to bed at the same time, and sleep longer, said Kyla Wahlstrom, Ph.D., a senior research fellow at the University of Minnesota. Wahlstrom conducted some of the first studies on the impact of school start time changes in the 1990s.

Every minute of delay helps, Wahlstrom said. When students get more sleep, she noted, their grades improve, attendance increases, tardiness falls, sports injuries drop, and rates of driving crashes decline.

Low achievers may benefit even more than high achievers from school start time delays, said Terra Ziporyn Snider, Ph.D., co-founder and executive director of Start School Later, a nonprofit organization advocating adoption of school start times that foster student health and safety. When struggling students get more sleep, she reported, they are more apt to go to school, arrive on time, pay attention, and graduate.

The Centers for Disease Control and Prevention (CDC) recommends that the nation’s middle and high schools start at 8:30 a.m. or later. Healthy People 2020—the CDC’s blueprint for improving the nation’s health—includes the goal of increasing the proportion of students in grades 9 through 12 who get sufficient sleep (defined as eight or more hours of sleep on an average school night), said Anne Wheaton, Ph.D., an epidemiologist in CDC’s Division of Population Health. In 2009, only 30.9 percent of U.S. students in grades 9 through 12 met that objective. In 2015, only 27.3 percent did so. The CDC seeks to raise that figure to 33.1 percent by 2020.

The adolescent sleep, health, and school start times conference was sponsored by the RAND Corporation, Yale School of Medicine Department of Pediatrics, Robert Wood Johnson Foundation, and Start School Later. ■

An abstract of Winsler’s report, “Sleepless in Fairfax: The Difference One More Hour of Sleep Can Make for Teen Hopelessness, Suicidal Ideation, and Substance Use,” can be accessed here. Healthy People 2020 is available here.