Just a little movement can cut waist size: study
CTV.ca News Staff
Published Tuesday, January 11, 2011 7:01PM EST
Researchers are offering some good news and bad news about jobs that keep you chained to your desk all day.
The bad news: too much sitting at work is bad for you. The good news: moving around even for just 60 seconds at a time is good for you, your heart and your waistline.
The findings come from one of the biggest studies to date on the effects of a sedentary lifestyle, tracking the daily movements of nearly 5,000 adults who took part in the U.S. National Health and Nutrition Examination Survey between 2003 and 2006.
To no one's surprise, the researchers found that, compared to people who spent the least amount of time sitting, people who spent the most time being sedentary in a typical week had:
- bigger waist circumferences
- lower levels of "good" HDL cholesterol
- higher levels of C-reactive protein (an important marker of inflammation)
But the researchers also found that the more breaks people took during the time they spent being sedentary, the smaller their waist circumference and lower their biomarkers of inflammation.
In fact, the top 25 per cent of people with sedentary workdays who took the most breaks had a waist circumference that was, on average, 4.1 cm smaller than those in the lowest 25 per cent.
The breaks didn't need to involve exercise; they could be as simple as getting up and walking around. And the breaks could be as short as 60 seconds for them to offer benefits.
The study, which appears in the European Heart Journal, was conducted by having participants wear a small device called an accelerometer, which monitors not only the amount of walking or running activity, but the intensity of it as well.
All the participants wore the device on their rights hip during waking hours for seven days. The least amount of sedentary time was 1.8 hours per day; the most was 21.2 hours per day. The least number of breaks over the full seven days was 99, and the most was 1,258.
Dr. Genevieve Healy, a research fellow at the School of Population Health at the University of Queensland in Australia who led the study, says it's well-accepted that moderate-to-vigorous intensity exercise provides health benefits. But the potential risks of prolonged sitting are something only just being realized.
She said her research highlights the importance of taking regular breaks throughout the day to just move around.
That could be a simple as walking over to a colleague's desk, rather than phoning or emailing, using the washrooms on another floor, or even making phone calls while standing up.
"The indications are that we should be getting up regularly. We think getting up every 30 minutes is a good starting point," Healy told CTV News.
Dr. David Lau, an endocrinologist who is also the president of Obesity Canada, says it's becoming clear that sitting for too long is simply not good for our health.
"This study has practical implications since most of us spend most of the day sitting at the computer working," he told CTV.
"This would be the first study to show that you can see benefits even with small changes in activity in the course of a day."
Dr. Mark Tremblay, the director of Healthy Active Living and Obesity Research at the CHEO Research Institute in Ottawa, says it's not clear why sitting for too long could be dangerous and why moving around can help.
"It may not be the movement per se that is causing the improvement; rather, the interruptions to the immobility," he speculates.
He says since so many of us aren't motivated to exercise, the advice to move around a number of times a day might be easier to follow.
"This might be a soft initial step to get people to interrupt their sedentariness on the long road to getting them to do more," he says.
Dr. Lau says he's long tried to incorporate exercise into his workday.
"If I spend time on the computer, I make sure I climb stairs 12 flights of stairs three or four times consecutively," he says.
"Every hour, get up and walk around, go to the washroom, walk around, do something that gets you away from your desk."
With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip