Sitting for eight hours a day doesn’t seem to raise your risk for dying early, according to a new analysis of previous studies—but only if you get at least an hour of exercise daily.
The results, published this week in the Lancet, may be reassuring for people stuck behind a desk all day, say health experts, but it should also serve as an important reminder: If you have to sit for long periods, your daily workout is vital to your well-being.
The connection between sitting and dying has been studied extensively, and has inspired many scary headlines in the media. And while this research didn’t actually look at any new data, it did combine information from 16 previous studies in a way than hadn’t been done before.
Using this data, researchers were able to directly compare death rates over a certain period of time between people with different levels of sitting time and physical activity. “Examining the joint effects of these two behaviors is important,” they wrote, “because most people engage in both behaviors every day.”
After crunching the numbers, the international team of researchers found that a sedentary lifestyle was indeed associated with an increased risk of death over the next decade. But the more people were active when they weren’t sitting, the more their risk went down. And for people who got the most daily exercise—at least 60 to 75 minutes of moderate physical activity—the increased risk disappeared completely.
In fact, those who sat for at least eight hours a day but were also in the highest exercise group actually had a lower risk of dying than those who sat for four hours or less but who reported the lowest amount of daily exercise (about five minutes a day).
The researchers also looked specifically at studies on television watching, rather than just sitting. Once again, they found that too much sedentary time—in these cases, at least five hours a day of TV viewing—was linked to early death.
But they also found one significant difference: In these studies, getting lots of exercise only seemed to lessen the risk of dying—not eliminate it completely. (The researchers don’t know why, but they speculate that TV watching may also involve snacking as well as sitting, making its harmful effects harder to counteract with exercise alone.)
Co-author Ulf Ekelund, PhD, professor of sports medicine at the Norwegian School of Sports Sciences in Norway, says that an hour a day of moderate physical activity is a good goal for many people. He points out, however, that exercise recommendations shouldn’t be the same across the board.
“I can’t stress enough that lower amounts of activity are also beneficial,” he says. And for people who are already getting an hour of exercise a day, they shouldn’t necessarily stop there—or use it as an excuse to be sedentary the rest of the time.
“The results suggest that the less you sit (or watch TV) and the more you are active the better,” he says. “The take-home message is ‘Sit less, move more—and the more the better.’”
That doesn't necessarily mean you have to live at the gym, adds Pam Peeke, MD, a national spokesperson for the American College of Sports Medicine and author of Fit to Live. Your physical activity can spread out throughout the day. "Get up for 5 to 10 minutes per hour when you're stuck at a desk," she suggests. "Go up and down stairs. Walk and talk on the phone using a headset." And when you can, schedule more deliberate exercise time, like a yoga class or a morning run with a friend. "It all counts—and will save your life."