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The downside of too much sitting

During the day, make an effort to stand rather than sit, when possible.

Standing up more throughout the day may help you dodge heart disease and live longer.

If you exercise for 30 to 60 minutes most days of the week, you’re doing your heart a big favor. But what are you doing during the rest of your waking hours? If the answer is “mostly sitting,” all that downtime could be putting you at risk for heart disease and an untimely death—even if you exercise up to an hour a day, new research suggests.

“We used to think of physical activity and sedentary behavior as mutually exclusive behaviors,” says exercise expert Dr. I-Min Lee, a professor of medicine at Harvard Medical School. Now, researchers understand that many physically active people also are sedentary, and that physical inactivity and sedentary lifestyle may be distinct risk factors that operate through different physiological mechanisms, she explains.

Regular exercise improves heart health. That’s why avoiding heart-pumping aerobic activity poses a risk. Being sedentary seems to be a separate risk, although exactly how it contributes to poor health isn’t clear. But some research suggests that sitting a lot has harmful effects on sugar and fat metabolism, both of which affect a person’s risk of diabetes and heart disease, says Dr. Lee.

A common conundrum

More than half of the average person’s waking hours are spent sitting: watching television, working at a computer, commuting, or doing other physically inactive pursuits, according to the new study, in the Jan. 19, 2015, Annals of Internal Medicine. Researchers pooled data from 47 studies looking at the health effects of sedentary behavior. They adjusted for other types of activity people did, from leisure activities to vigorous exercise.

Compared with people who spent less time sitting, people who sat for prolonged periods of time had higher rates of heart disease and were more likely to die from any cause, even if they exercised regularly. These effects were even more pronounced in people who did little or no exercise.

One way to look at this is over a full day, says Dr. Lee. “If you sleep for eight hours, that leaves 16 hours. Even the most physically active among us, who exercise one or even two hours a day, still have 14 hours to fill, which is a lot of time.” Spending eight hours at a sedentary job is part of the problem. Earlier studies looking at the health effects of different occupations hinted at this association.

The federal recommendations for physical activity (see www.health.harvard.edu/PAguide ) are based on decades of research. There aren’t any specific guidelines on how much sitting is too much, because the concept is relatively new. But several large-scale studies in which participants wear devices to quantify how much they move during the day are currently under way. Still, it’s clearly a good idea to decrease your sedentary time throughout the day. Start by becoming more conscious of how much time you’re sitting, advises Dr. Lee.

Once you’re aware of the possible problem, the next step is staying motivated. Fear of an early death doesn’t usually motivate people to change their habits, but losing weight might be an incentive. You burn 30% more calories when you’re standing than when you’re sitting down. It’s not a huge amount, but it adds up over time and can contribute to weight control, says Dr. Lee. 

Start moving more

Following are four ways to spend less time sitting. “The key is to make these things habits that you do without thinking about them, like brushing your teeth,” says Dr. Lee.

  1. Set a timer. Set the alarm on your smartphone or computer, or get a regular kitchen timer and set it to go off every 30 to 60 minutes during the day when you tend to sit for long periods of time. When it rings, get up and walk around, or do some simple exercise for a few minutes.

  2. Pace during phone calls. Whenever you’re on the phone, stand up. Try to walk back and forth or in circles while you talk.

  3. Turn commercial breaks into workout breaks. Use the two- or three-minute commercial breaks while you are watching TV to stand up. March in place, swing your arms, or do some squats or leg lifts.

  4. Take the long way. Whenever you drive somewhere, park in a spot farther from the door to get in some extra steps.

Images: Thinkstock

Posted by: Dr.Health

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