Yes, exercise is good for you. This we know. Heaps of evidence point to the countless benefits of regular physical activity. Federal health officials recommend at least 30 minutes of moderate exercise, like brisk walking, every day.
Studies show that when you adhere to an exercise regimen, you can improve your cardiovascular health, lower blood pressure, improve metabolism and levels of cholesterol and triglycerides. You can reduce diabetes risk and the risk of certain cancers. And, finally, exercise can help maintain a healthy weight, which can boost all these benefits even more.
But now, researchers are beginning to suspect that even if you engage in regular exercise daily, it may not be enough to counteract the effects of too much sitting during the rest of the day.
Epidemiologist Steven Blair is a professor of public health at the University of South Carolina. Blair has spent 40 years investigating physical activity and health.
"Let's say you do 30 minutes of walking five days a week (as recommended by federal health officials) and and let's say you sleep for eight hours," says Blair. "Well, that still leaves 15.5 hours" in the day.
Lots of us, he points out, have sedentary jobs and engage in sedentary activities after work, like watching television or sitting around a dinner table talking. When you add it all up, Blair says, "it's a lot more sitting than moving."
Blair recently headed a study at the University of South Carolina which looked at adult men and their risk of dying from heart disease. He calculated how much time the men spent sitting, in their cars, at their desk, in front of the TV.
"Those who were sitting more were substantially more likely to die," says Blair.
Specifically, he found that men who reported more than 23 hours a week of sedentary activity had a 64 percent greater risk of dying from heart disease than those who reported less than 11 hours a week of sedentary activity. And many of these men routinely exercised. Blair says scientists are just beginning to learn about the risks of a mostly sedentary day.
"If you're sitting, your muscles are not contracting perhaps except to type. But, the big muscles like in your legs and back are sitting there pretty quietly," says Blair. And, because the major muscles aren't moving, metabolism slows down.
"We're finding that people who sit more have less desirable levels" of cholesterol, blood sugar, triglycerides and even waist size, says Blair, which increases the risk of diabetes, heart disease and a number of health problems.
'Our Body Just Kind Of Goes Into Shut Down'
Dr. Toni Yancey is a professor in the department of health services and co-director of the Kaiser Permanente Center for Health Equity at the University of California, Los Angeles. For years, she's worked on developing programs to motivate people to get up and move.
"We just aren't really structured to be sitting for such long periods of time and when we do that, our body just kind of goes into shut down," says Yancey.
Yancey recommends routine breaks during a full on day of sitting. Her book, Instant Recess: Building A Fit Nation 10 Minutes At A Time, offers readers a guide on how to initiate such activity in the corporate boardroom, school classroom and even at sporting events.
But even if your work site doesn't engage in routine hourly breaks, there are things individuals can do at their desks to break up a day of inactivity and get moving, even if just for a few minutes. Yancey recommends just a few minutes every hour.
And she suggests sitting on an exercise ball instead of a desk chair, adding that it helps strengthen the core while improving balance and flexibility. It also requires more energy, so a few calories will be burned.
It may not sound like much, but an Australian study found that these types of mini-breaks, just one minute long, throughout the day can actually make a difference. You can simply stand up, dance about, wiggle around, take a few steps back and forth, march in place. These simple movements can help lower blood sugar, triglycerides, cholesterol and even waist size.
"If there's a fountain of youth, it is probably physical activity," says Yancey, noting that research has shown benefits to every organ system in the body.
"So, the problem isn't whether it's a good idea," she says. "The problem is how to get people to do more of it." Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.