Although plenty of studies show that the natural sleep cycle of teenagers skews late, school hours start early. In addition to health problems, sleep deprivation can cause lower academic performance and increased risk of accidents.
The American Academy of Pediatrics (AAP) recently issued a new policy statement supporting the idea of a later start time for middle and high school. The academy recommends starting no earlier than 8:30 a.m., it says, to “align school schedules to the biological sleep rhythms of adolescents, whose sleep-wake cycles begin to shift up to two hours later at the start of puberty.”
The September issue of the journal Pediatrics published the statement, “Insufficient Sleep in Adolescents and Young Adults: An Update on Causes and Consequences,” which referred to research showing that adolescents who get enough sleep enough lower their risk of being overweight, suffering depression and being in an automobile accidents. They also get better grades and report a better quality of life, according to Dr. Judith Owens, a pediatrician and lead author of the policy statement.
“Chronic sleep loss in children and adolescents is one of the most common – and easily fixable – public health issues in the U.S. today,” she said.
Mark Fischetti, a senior editor at Scientific American, voiced strong support for the movement toward later school hours.
“Ask any groggy teenager waiting for a bus or yawning in ‘home room,’” he wrote, “and he or she will tell you that it’s just too darn early in the morning to learn chemistry equations or analyze a narrative by some Russian novelist.
“Are they just lazy? No. Scientific studies of teen sleep patterns say they’re right. So do results from numerous schools across the country that have delayed start times: The later classes begin, the more academic performance improves. Bonus points: attendance goes up, teen depression goes down, and fewer student drivers get into car crashes.”
It’s all about circadian rhythms, the biological clock that makes you feel awful when you travel across several time zones (jet lag) and can disrupt workers whose shifts change from day to night to day.
Circadian rhythms, Fishchetti noted, shift during the teen years. Starting around age 13 or 14, the kids naturally stay up later and sleep later, a pattern that peaks between 17 and 19. Adolescents also need more sleep than an adult.
One study of 9,000 high school students in three states showed that grades in science, math, English and social studies rose when school began at 8:35 or later. Experiments at two North Carolina high schools and at the U.S. Air Force Academy also showed that academic performance improved when start times were later.
School districts might be reluctant to revise what they’ve always done, but Fischetti reported that their concerns about starting school later aren’t fulfilled — kids still can hold an after-school job, and participate in after-school programs.
“The issue is not the start time. It’s that the students are overly busy,” said Kyla Wahlstrom, one of Fischetti’s sources. “There is too much pressure to cram it all in just to have a good resume to get into college.”
Wahlstrom is director of the Center for Applied Research and Educational Improvement at the University of Minnesota. She said students, parents and school advisors should ratchet back the activities, and emphasize certain ones they enjoy or do well at, rather than participate in order to impress colleges. She said students should get eight, and preferably nine, hours of sleep every night.
Other countries seem to be learning this lesson. Studies in Brazil, Italy and Israel associate later start times with improved learning, and high-school level students in Europe seldom start before 9:00 a.m.
Even if it’s not about academics, it’s about safety. Fischetti referred to a high school in Wyoming that moved the start time from 7:35 a.m. to 8:55 a.m. and saw a 70% reduction in car crashes among drivers ages 16 to 18.
University of Kentucky researchers studied the issue and found that crash rates of teen drivers fell 16.5% in the two years after start times were delayed one hour, while the teen crash rate where they remained the same rose 7.8% in the same time period. The students in each of those groups, respectively, slept different amounts. In the reduced-crash group, those who got at least eight hours of sleep during weeknights rose from 36% to 50% percent, and those who got at least nine hours rose from 6% to 11%.
Your teen probably isn’t willing to go to bed earlier, and if he or she does, might not be able to fall asleep. But almost all of them would be willing to sleep later.
It’s time for school districts to wake up and smell the coffee.