High school students sit for too long, new health research suggests
High school seniors are a tough crowd at 7:30 in the morning — even for Josh Maisel, a veteran, charismatic teacher who scores a 24 out of 25 popularity points on RateMyTeachers.com.
On a recent Thursday in their Fremont High School classroom in Sunnyvale, Calif., students rested their heads on the miniature desks in front of them; or they sat upright, but seemed to stare into some other, non-classroom reality – deadpan despite their teacher’s “in my day…” caricature of their grandparents. It was as if the whole class was gathered in a dream world.
But then, about two-thirds of the way into the 90-minute period, Maisel told them to get up and walk around – to move their desks into little clusters for a group activity.
The change in energy was obvious and immediate.
Kids laughed and chatted as they moved into their new seats; and even after settling down appeared to be more genuinely engaged — in a lesson about gross domestic product, nonetheless.
“In a traditional class, the teacher stands and talks, and the kids sit,” Maisel said. “But a lot of us know that that’s not good teaching.”
What Maisel didn’t articulate is that incorporating a little burst of low-level physical activity was also helping combat a feature of the high school environment that new research is showing to be correlated with obesity, heart disease and Type-2 diabetes: prolonged sitting.
Those health crises are so severe and costly that many of us have become immune to the statistics. But they bear repeating: More than a third of U.S. adults and 17 percent of U.S. children are obese, according the Centers for Disease Control and Prevention. The associated medical cost is around $147 billion per year. For example, last year nearly 27 percent of U.S. adults age 65 and older had Type-2 diabetes, a very expensive disease.
“One of the problems with our school system,” said Anne L. Friedlander, vice president of programs at ConnectWell and a consulting professor in the human biology program at Stanford, “is we have all these kids, and they’re running around, and they’re very energetic, and they’re playing all these games. And then we take them into school, and we say, you know, ‘Sit down and be still.’ And it’s one of the worst things we can do for their health.”
Friedlander was one of 20 researchers who gathered at Stanford University this past summer to host a rather ironic gathering: a conference on the science of sitting. (The press release for the event spawned a predictable word-play frenzy: “Standing room only at Stanford sitting-risks event” and “Well-attended Stanford conference, with many empty seats…”)
The takeaway was simple: Sitting is not only harmful because it represents a lack of exercise; but also because sedentary behavior initiates a unique cascade of physiological changes that lead to a higher concentration of fat in the blood, insulin resistance, Type-2 diabetes, heart disease and obesity – even in those people who meet the recommended 150 minutes per week of moderate to intense aerobic activity.
These are all effects that come into play when the body’s postural muscles aren’t engaged.
Postural muscles are a specific type of muscle fiber that handle low-intensity activity. They’re essentially what hold you upright during the day, whether you’re walking, standing or even trying to stay balanced while sitting on a yoga ball. They process lipids, or fat in the blood, differently than the muscles that engage during activities like running or biking.
“It’s a unique thing that happens when you’re standing up and walking around,” Friedlander said, “which is what we did for all of our evolutionary lifetime.”
Numerous recent peer-reviewed studies have documented the ramifications of prolonged sitting. A large-scale Australian study found that adults without known diabetes who sat for long periods of time had higher rates of abnormal glucose metabolism; another found that, among chronic sitters, those who took more frequent breaks experienced fewer negative health consequences.
Researchers are also looking back over historical literature to shed light on the field of “inactivity physiology,” and the conclusions of those epidemiological observations are striking.
Scientists in the mid-1900s, for example, found that men who sat for long periods of time at work were twice as likely to develop heart disease as were men who moved around throughout the day. English bus drivers were more likely to suffer from heart attacks than bus conductors; mail sorters were more likely to suffer from heart attacks than mailmen.
While recent research has focused on adults, Friedlander said, there’s no obvious reason to think the findings shouldn’t be applied to kids.
If anything, they’re more constrained for longer periods of time than their office-dwelling parents, most of whom enjoy the liberty of an occasional walk to the restroom or water cooler.
But all of this raises one obvious question: How much sitting is too much?
Aliaa Aal Abdulrasul, a senior in Maisel’s first-period economics class, spends four-and-a-half hours in various desks at Fremont High Monday through Thursday, and six hours on Friday.
The same goes for freshmen and sophomores, who don’t have the luxury of a free period, but who are required to take physical-education classes.
Juniors typically spend as many as six hours in a desk every day of the week.
Friedlander said researchers haven’t settled on an answer, but – as with sun exposure and skin cancer risk — the figure probably won’t be the same for everyone.
“The idea is sort of that less is better,” she said. “Some people could probably sit for a long time and not develop negative health consequences. Others need to be getting up more often and having more vigorous breaks.”
Tweaking the high school schedule could improve student health
Parents and school administrators have spent a lot of time in recent years trying to settle on the perfect bell schedule. Much of the shuffle has been part of a larger movement toward later start times, in response to research showing teens naturally stay up later and need more sleep. Some has of it has targeted overall stress levels.
Palo Alto High School switched to a straight block schedule this year, which allows 25 minutes of extra sleep time in the morning for students. Menlo-Atherton pushed back the morning bell, too, from 7:50 to 8:45 a.m. three days per week, and 9:30 a.m. two days per week.
Block schedules are generally favored by English, physical education and social studies teachers, but disliked by Spanish and math teachers, who say daily exposure is important to memorization.
The newer schedule means students must sit still for 90 minutes, almost double the old standard.
James Maa, a junior at Palo Alto High School, said he values the later start time but severely misses the shorter class times and more frequent breaks.
“I feel pretty restless most of the time,” he said.
“P.E. is not the solution”
Of course, outside of academic class time, high schools present abundant opportunities for athletic endeavors. Palo Alto and Fremont high schools each offer 16 sports teams, ranging from badminton and golf to water polo and football.
And physical education is required for students through their sophomore year.
But teenagers self-select for activities. Those who are already physically active generally opt for high-intensity sports, while those who might benefit most from physical education classes can sail through with minimal involvement or exertion.
“P.E. is not the solution,” said Maa, who plays both high school and club soccer. “The lazy or physically inactive people do the bare minimum amount of work that it takes to get by.”
Many students walk the mile rather than run it, Maa said, or they skip laps; and teachers spend excessive amounts of time just picking teams. He estimated real aerobic activity lasted 10 or 15 minutes under the old 50-minute period.
Peter Diepenbrock, the head of the physical education department at Palo Alto High School, said the curriculum isn’t just about making sure students get high-intensity aerobic activity, like running, push-ups or sit-ups. It’s also about just getting them to be “comfortable” with the various activities – whether the unit is swim, “rhythms,” self-defense, track or weight training. And he said the current block schedule allows more time for actual movement.
But beyond the robust school coffers of the Bay Area, there’s a trend away from extracurricular courses that offer opportunities for high-intensity and low-level physical activity alike, said David Plank, executive director of the research center Policy Analysis for California Education.
“The general press is toward intense focus on basic academic skills, on what gets tested,” he said. “Physical education, along with art, music and several other subjects, doesn’t get tested.”
Rethinking the classroom environment
Of course, whether or not physical education classes are offered, or are as rigorous as they could be, is something of a moot point. The disturbing takeaway from new research on sedentary behavior is that short bursts of aerobic activity simply can’t compensate for long periods of sitting.
That’s why Friedlander and others think simple innovations in the classroom environment could provide the best health bump for school-budget bucks. The changes could be as simple as inserting an official 10-minute break in 90-minute class periods (a move Susan Shultz, a guidance counselor at Palo Alto High School said is under consideration); bringing standing desks and yoga balls into classrooms; or simply training teachers to incorporate more physical activity into their lesson plans.
“It’s so hard to get people to go out and exercise,” Friedlander said. “But if you have the environment that promotes movement in everyday life, then you get health benefits without really noticing that you’re getting them. I think that’s where a lot of the impact comes in — to sort of remove some of the personal choice.”
Maisel agreed. He wouldn’t continue to tweak the time schedule but would simply train teachers to incorporate more movement during class. At least a third of the 90-minute class should be something that’s more active for the students than sitting and listening, he said. “Preferably standing and moving around in some way.”
Plank said the emphasis on test scores, which pressures teachers to often overlook the importance of creativity and physical health in their classrooms, extends beyond high school to even younger students.
“Try to imagine a 9-year-old sitting for six hours drilling math facts,” Plank said, “and how much fun that would be, and how much enthusiasm that would generate in that student. And then say, is this really what we want school to be about? Do we just want to chain kids to their desks and keep them there till they can add three-digit numbers? Or do we want kids to actually maybe like coming to school?”
After all, he added, encouraging movement through environmental and behavioral cues has been shown to improve student concentration; it’s just smart pedagogy.
And if you think about the magnitude of the obesity and Type-2 diabetes crises, influencing adolescent behavior in the last setting where they’re subject to strict institutional control would seem to be smart from an economic perspective as well.
“The idea that we don’t need to pay attention to those things,” he said, “that we’ll just pay attention to instruction, I think is shortsighted and probably misguided.”