Ethan Boroson is an honor student and captain of the baseball team, the kind of boy who makes teachers and other students smile on sight. Though often tired, he’s succeeding. But most high school students fare less well, and lack of sleep is one of the reasons. Mary Carskadon, a professor of psychiatry and human behavior at Brown University and director of chronobiology and sleep research at Bradley Hospital, studies sleep in adolescents and has found that many of them “live in a state of jet lag continually.”
The consensus in the field — informed by a large Centers for Disease Control and Prevention survey of American teens — is that adolescents need about nine hours and 15 minutes of sleep a night, but most get less. Teens are caught in a tug of war between their biology and rules and schedules put in place by adults. Biology is losing.
Adults are disinclined to sleep during the day. Teenagers, however, are hard-wired to be night owls. Their circadian rhythms are timed later than those of other age groups and will remain so into their early 20s. When adults who work a typical day shift start winding down in the evening, an adolescent’s energy and alertness are peaking. The average adolescent isn’t ready — or perhaps even able — to go to sleep until 11 p.m. or later.
Hormones play a role. Our brains produce the hormone melatonin as they prepare to sleep. Synthetic forms are sold over the counter as a sleep aid. Carskadon found that melatonin levels in adolescents don’t rise until about 10:30 p.m. Sending your teen to bed at 10 is likely to lead to tossing and turning but not much sleep until the body agrees it is time. If a child who can’t sleep until 11 p.m. needs to rise at 6 a.m. to catch a bus, that provides just seven hours of sleep — two hours less than the average adolescent needs.
Changing School Start Times Causes Alarm
If, as the science says, teens are more alert and healthier when they sleep later, why haven’t more high schools adjusted their start times? The answer to that question lies in a mix of logistics and politics. See Colleen Shaddox’s story titled “Delaying School Start Times Causes Alarm” on Miller-McCune.com.
Furthermore, melatonin secretion is still high in adolescents in the early morning hours. During these hours, teens may be in the “rapid eye movement” phase, a period characterized by a high-quality form of sleep that the mind and body need to be fully refreshed. Many parents can testify to just how difficult it is to rouse a sleeping teenager.
Typical high schools in the United States open at about 7:30 a.m. But some communities have adjusted school start times in an effort to synch high school students’ schedules to their body clocks, and the quantitative results have been largely positive, including better attendance and reduced traffic accidents. There is also anecdotal testimony from teachers and parents that better-rested teens are more cheerful and cooperative teens. The change comes with logistical challenges, though. As school districts around the country debate later start times, meetings tend to get heated.