The Surprising Effects of Too Much Sitting
Safety Note: Talk to your doctor before making any big changes to your exercise plan.
Here’s a statistic you shouldn’t take sitting down: The average person spends eight hours a day seated, according to a poll of almost 6,300 people by the Institute for Medicine and Public Health. And unless you break it up, all that sitting—whether it’s behind the wheel, in front of the television, or at the computer—increases your risk for cardiovascular disease, type 2 diabetes, obesity, and early death. For adults with type 2 diabetes, it’s also linked to poorer blood glucose management.
“Labor-saving devices are killing us,” says exercise physiologist Gary Scheiner, MS, CDE, owner and clinical director of Integrated Diabetes Services. “All the inventions and innovations of the last 100-plus years that save us from doing any kind of physical work are counterproductive. Our bodies were made to move, and when we don’t, our bodies fail us.”
Here’s why: The muscle activity needed for even low-level movement, such as standing—never mind something more vigorous like walking—triggers important processes related to the breakdown of fats and sugars within the body. When you sit, these processes stall, and your health risks increase.
But “breaking up sedentary time with physical activity of some sort interrupts what would be an otherwise bad process,” says Sheri Colberg-Ochs, PhD, professor emerita of exercise science at Old Dominion University in Norfolk, Virginia. “In order to stand upright, you have to use the muscles that we use for basic balance. You’re not using up a lot of calories, but you’re still using up some.” And doing any sort of activity—even a small amount—allows your metabolism to remove glucose from your bloodstream and reduce fat levels in your blood, both of which lower insulin resistance.
That’s why the American Diabetes Association’s 2017 Standards of Medical Care in Diabetes now recommends that everyone—not just people with or at risk of developing diabetes—get up every 30 minutes and stand, walk, or do some other form of light activity (see “4 Ways to Move More, Sit Less,” below). Research published in a 2016 issue of Diabetes Care showed that, for adults with type 2 diabetes, breaking up bouts of sitting every half hour with three minutes’ worth of movement—a leisurely walk or simple resistance moves such as standing push-ups against a wall or counter—improves blood glucose levels, compared with uninterrupted sitting. (The effect has not been studied in adults with type 1.)
“The most effective way to improve insulin sensitivity is to use your muscles—even if it’s just getting up more often,” says Scheiner. “Active muscles are very efficient at using insulin.” That, in turn, lowers blood glucose levels.
Now for the surprising part: Even if you meet the ADA’s recommended guidelines for exercise—at least 150 minutes per week of moderate-intensity aerobic activity such as swimming, plus at least two strength-training sessions and two sessions aimed at improving balance and flexibility—you’re still at risk. Unless, that is, you break up prolonged sitting with a few minutes of light activity throughout the day.
“You think that one hour at the gym is enough, but it’s not,” says Colberg-Ochs. According to a recent analysis of 16 studies published in The Lancet, high levels of moderate-intensity physical activity—that’s about 60 to 75 minutes per day of something like brisk walking or swimming—reduce the health risks associated with prolonged sitting, but they do not eliminate them. Moderate-intensity exercise is still important. It’s just not sufficient to offset the hazards of nonstop sitting.
Consider all of that added incentive to stand up. After all, “people who are physically active have a better quality of life,” says Scheiner. “They’re happier, more satisfied, get sick less, and can do more things.”
If you have difficulty standing or walking, try one of these moves instead: March in place from a seated position, do arm curls with light hand weights, place your hands on the arms of your chair and lift yourself up and down, or simply reach for the ceiling.
4 Ways to Move More, Sit Less
Set a reminder.
To get into the habit of standing up every half hour, set the alarm on your phone, install a timer app on your computer, or use an old-fashioned egg timer. And let mealtime be your reminder to exercise after eating. “Studies show if you do some form of physical activity after you eat, you can prevent or at least dampen post-meal [blood glucose] spiking,” says Colberg-Ochs.
Wear a pedometer.
It’ll encourage you to move more by showing you how many steps you’ve taken. Before you change your sedentary ways, wear it for a few days to get a baseline of your activity level, suggests Scheiner. Then start moving more—and see the results.
Work on your feet.
Return e-mails, texts, and phone calls standing up.
Wear comfy shoes.
They don’t have to be as comfortable as your sneakers, but they shouldn’t be a hindrance to moving more often.
Did You Know?
Research published in a 2015 issue of the International Journal of Behavioral Nutrition and Physical Activity looked at the impact of television watching on older adults and found that those who watch more than five hours a day had a 28 percent greater risk of early death than those who watch less than three hours a day.