Mounting evidence suggests that sitting for long periods increases the risk of obesity, diabetes, cancer and early death, even for people who exercise daily. And yet Americans now sit more than they sleep, spending an average of 10 hours a day in a car, at work and in front of a television. Older adults are the worst offenders, according to federal government statistics: Almost three-quarters are sedentary, and more than four in 10 get no leisure-time physical activity at all.
See also: Walking: The easiest exercise.
To reduce your cancer risk, the American Institute of Cancer Research is urging Americans to add mini-breaks from sitting to a daily regimen of getting at least 30 minutes a day of moderate-to-vigorous exercise.
"If you reduce sitting by five minutes an hour, at the end of a long day, you've shaved an hour off your total sitting time," says Alpa Patel, M.D., senior epidemiologist with the American Cancer Society. That advice applies as well to "active couch potatoes," who hit the gym or take that daily brisk walk, because some research indicates daily exercise is not enough protection from the harmful effects of a sedentary lifestyle.
Physical activity in the workplace has fallen, too, according to a recent study. Fifty years ago, more than half of American jobs involved moderate physical activity, often in manufacturing or agriculture, reports Pennington Biomedical Research Center in Baton Rouge, La. "Today it's less than 20 percent — we're tied to our desks," says Tim Church, M.D., a Pennington professor and the study's lead author.
Last year, registered dietitian Jill Weisenberger wrote a book and started worrying about sitting too much. "I jog every morning, but what about the other 23 hours a day? I've read that sitting makes the blood vessels less elastic, and I didn't want to be a jogger and a dietitian with heart disease," says Weisenberger, 50, of Yorktown, Va. At home she began walking a circuit while cooking dinner. Then she bought a desk equipped to fit over a treadmill and now logs 30 to 35 miles a week walking at 1.4 miles per hour. "I can type, read email, surf the Net — anything except have pretty handwriting," she says.
The Cancer Society's Patel stands during conference calls, uses a printer in another office, and eschews email and the telephone to walk over to a colleague's office. She also sits on an exercise ball. "It's called 'active sitting.' If you slouch you fall off," she says. She takes a brisk 20-minute walk at lunch, adding longer walks before or after work. By reducing sitting time and ramping up physical activity, Patel also lost 40 pounds in six months.
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Elizabeth Pope is a writer based in Portland, Maine.