Sleep and the Teenage Brain
By Maria Popova
“Sleep is the greatest creative aphrodisiac,” Debbie Millman asserted in her advice on breaking through your creative block. “Sleep deprivation will profoundly affect your creativity, your productivity, and your decision-making,” Arianna Huffington cautioned graduating seniors in her Smith College commencement address on redefining success. And yet, as German chronobiologist Till Roenneberg argued in his fantastic Internal Time: Chronotypes, Social Jet Lag, and Why You’re So Tired — one of the best science books of 2012, and undoubtedly among the best you’ll ever read — teenagers have already endured years of institutionally inflicted sleep deprivation by the time they get to college: there is a tragic disconnect between teens’ circadian givens and our social expectations of them, encapsulated in what is known as the disco hypothesis.
In Dreamland: Adventures in the Strange Science of Sleep (public library) — the fascinating exploration of what happens while you sleep and how it affects your every waking moment, and also among the best science books of 2012 — David K. Randall makes an empirically striking case for just how profound the impact of sleep-cycle misalignment is on teenagers, not only academically but also socially, psychologically, and emotionally:
Biology’s cruel joke goes something like this: As a teenage body goes through puberty, its circadian rhythm essentially shifts three hours backward. Suddenly, going to bed at nine or ten o’clock at night isn’t just a drag, but close to a biological impossibility. Studies of teenagers around the globe have found that adolescent brains do not start releasing melatonin until around eleven o’clock at night and keep pumping out the hormone well past sunrise. Adults, meanwhile, have little-to-no melatonin in their bodies when they wake up. With all that melatonin surging through their bloodstream, teenagers who are forced to be awake before eight in the morning are often barely alert and want nothing more than to give in to their body’s demands and fall back asleep. Because of the shift in their circadian rhythm, asking a teenager to perform well in a classroom during the early morning is like asking him or her to fly across the country and instantly adjust to the new time zone — and then do the same thing every night, for four years.
Randall points out that those early school start times originated in an era when youths either had a job after school or had to complete chores on the farm, so the schedule was designed to fit everything in; thus, the teenage circadian rhythm has only become problematic in the past century or so. (Even the very term “teenager” was only coined in the 1930s.) But despite dramatic cultural shifts that have since significantly reduced, if not eliminated, those labor-intensive after-school responsibilities and replaced them with recreational activities like athletics, band practice, and art extracurriculars, the biologically unreasonable early class start times have failed to evolve accordingly. The consequences, it turns out, are far graver than mere teen angst directed at the alarm clock or the unfortunate awakening parent:
The lack of sleep affects the teenage brain in similar ways to the adult brain, only more so. Chronic sleep deprivation in adolescents diminishes the brain’s ability to learn new information, and can lead to emotional issues like depression and aggression. Researchers now see sleep problems as a cause, and not a side effect, of teenage depression. In one study by researchers at Columbia University, teens who went to bed at 10 p.m. or earlier were less likely to suffer from depression or suicidal thoughts than those who regularly stayed awake well after midnight.
Randall highlights a radically simple solution proposed by a school in Edina, Minnesota, in the mid-1990s:
Since students who were awake were more likely to learn something than those who were asleep, the board decided to push the high school’s starting time an hour and five minutes later, to 8:30. It was the first time in the nation that a school district changed its schedule to accommodate teenagers’ sleeping habits.
But the response, bespeaking a questionable hierarchy of priorities, wasn’t what the educators expected:
Some parents complained that the new schedule would take time away from after-school sports and school clubs. Others said that they needed their children home to babysit their siblings. Yet the most persistent complaint was that pushing the start time back wouldn’t result in better-rested kids, but the opposite. Critics argued that teenagers would simply use the time to stay up later, compounding the problem and making their parents’ lives yet more difficult.
The school, however, stuck with the plan for the academic year. A researcher assigned to assess how school policies affect students set out to explore the impact of the experiment through extensive interviews with students, parents, coaches, and teachers. A year later, she presented her unambiguous findings:
Despite the fears of some parents, teenagers did in fact spend their extra hour sleeping, and reported that they came to school feeling rested and alert. At the same time, the number of on-campus fights fell, fewer students reported feeling depressed to their counselors, and the dropout rate slowed. Coaches pushed back practice times until later in the afternoon, and participation didn’t suffer.
The results were also quantifiable: The average SAT score for the top 10% of Edina’s students rose from 1288 to 1500 out of 1600 following the implementation of the new schedule. Even the head of the College Board, that institution behind the ominously familiar standardized test, proclaimed the results “truly flabbergasting.”
But perhaps most remarkable of all is the privilege-blindness of the results: After the success in Edina — a wealthy, mostly white suburban school — Minneapolis, where the majority of students come from minority families with income low enough to qualify them for government-subsidized school lunches, pushed its high school start times from 7:15 to 8:40. The results didn’t flounder: Like their suburban counterparts, Minneapolis students’ grades improved, their drop-out rates fell, and they attended first-period classes more regularly. Achieving the same unflinching results despite enormously different socioeconomic variables demonstrated that sleep habits aren’t culturally primed but are deeply biological. The implications of this, Randall writes, extend far beyond the merely academic:
Other districts followed suit, and found effects that sometimes went beyond scholastics. In Lexington, Kentucky, for instance, pushing the starting time back led to a 16 percent reduction in the number of teenage car accidents during a year in which teenage accident rates rose 9 percent for the state as a whole. In Rhode Island, pushing starting times back a half hour resulted in a forty-five-minute increase in the average amount of time that the average student spent sleeping. ‘Our mornings are a whole lot nicer now,’ the lead researcher of the study, whose daughter was a high school student, said at the time.
Allowing children to get additional sleep may help solve the problem of school bullying as well. A 2011 University of Michigan study tracked nearly 350 elementary school children. About a third of the students regularly bullied their classmates. Researchers found that the children with behavioral issues were twice as likely to have excessive daytime sleepiness or to snore, two symptoms of a persistent sleep disorder. Louise O’Brien, an assistant professor of sleep medicine University of Michigan who was part of the research team, argued that “the hypothesis impaired sleep does affect areas of the brain. If that’s disrupted, then emotional regulation and decision-making capabilities are impaired.”
Public domain photographs via Flickr Commons
Published July 17, 2013