As summer winds down, another new school year brings fresh notebooks, sharp pencils and — for many kids — a new cycle of sleep deprivation.
With classes that start as early as 7 a.m. and buses that pull up long before sunrise, some 80% of American kids in grades 6 through 12 are falling short of sleep recommendations during the school year, according to research by the National Sleep Foundation, a sleep advocacy group.
Now, fueled by accumulating research showing that adolescent bodies are designed to sleep late and that delaying school start times — even by just 30 minutes — makes a huge difference in how well teens feel and perform, an increasing number of schools around the country are ringing morning bells later than they used to. Many more are thinking about it.
At the same time, however, there are strong pockets of resistance to change from administrators and parents who think that bus schedules will get too complicated, that starting later will interfere with after-school programs or that kids simply will stay up later if they know they can sleep in a little more.
Despite the inconveniences involved in district-wide changes, sleep researchers emphasize the need to view sleep, like food and exercise, as a pillar of health.
"There are all these other things we do to ensure success for our kids, and getting them to have adequate sleep is probably one of the most important things you can do," says Judith Owens, a sleep researcher at Brown Medical School in Providence, R.I. "Parents need to take this as seriously as eating right, using seatbelts and putting on sunscreen."
One of the first, longest-lasting and most influential teen sleep experiments started in Minnesota in the mid-1990s. Around that time, Minneapolis high schools shifted start times from 7:15 to 8:40. The nearby suburb of Edina shifted from 7:25 to 8:30.
Even though the two districts couldn't be more different on scales of race, socioeconomics and other factors, results in both places appeared immediately, says Kyla Wahlstrom, director of the Center for Applied Research and Educational Improvement at the University of Minnesota, Twin Cities.
Students were noticeably more alert in the first two periods of the day. The cafeteria was calmer. There were fewer fights in the halls. Students, who were now getting nearly an hour more sleep each night, said they felt less depressed. They were raising their hands instead of falling asleep at their desks. Even parents thought their kids were easier to live with.
Over time, Wahlstrom and colleagues documented, students started getting better grades on homework and quizzes. Schools reported lower tardiness rates. Attendance rates went up. Graduation rates improved.
"We found clear evidence of more kids staying in school and not dropping out," Wahlstrom says. "Every group — principals, teachers, parents and kids — had something to say about it."
Since then, reports from places such as Brazil, Israel and Rhode Island have turned up similar trends. Even small changes in school start times appear to make big differences.
In one of the most recent studies, published last month in the Archives of Pediatric & Adolescent Medicine, Owens and colleagues found that, after a change in start time from 8 to 8:30 a.m., students at a small, private New England high school reported fewer depressed feelings (a shift from 65.8% to 45%), better moods (from 84% reporting irritated and annoyed feelings to 62.6%); and less sleepiness during the day. (Before the shift, 69.1% of students said they rarely or never got a good night's sleep compared with 33.7% after the shift, for example.)
Class attendance improved: Teacher-reported first-class absence and tardiness rates dropped by 45%. Fewer students visited the health center (from 15.3% of students to 4.6% of students).
"Virtually every single parameter we looked at changed in the positive direction," Owens says. "We still saw substantial percentages of students reporting daytime sleepiness and depression. It wasn't a panacea. But there was a really dramatic improvement in everything."
Sleep seems to beget sleep, the study suggested. Even though the new schedule started just 30 minutes later, students actually went to bed 15 minutes earlier and got 45 more minutes of sleep each day. When interviewed, kids said they felt so much better from even a little bit of extra sleep that they were motivated to go to bed sooner and sleep even more. Owens suspects that the extra sleep also helped them get their homework done more efficiently, affording them extra time in the evening to wind down and get to bed.
"These kids get into a vicious cycle of being exhausted, taking five hours to do three hours of homework and having to stay up later to get it done," she says. "As they're getting less sleep, they have to stay up later and they get even more tired."