Excessive sitting deadly, despite daily exercise
TORONTO — Sitting on one’s butt for a major part of the day may be deadly in the long run — even with a regimen of daily exercise, researchers say.
In an analysis that pooled data from 41 international studies, Toronto researchers found the amount of time a person sits during the day is associated with a higher risk of heart disease, diabetes, cancer and death, regardless of regular exercise.
“More than one half of an average person’s day is spent being sedentary — sitting, watching television or working at a computer,” said Dr. David Alter, a senior scientist at the Toronto Rehabilitation Institute, who helmed the analysis. “Our study finds that despite the health-enhancing benefits of physical activity, this alone may not be enough to reduce the risk for disease.”
The paper, published Monday in the Annals of Internal Medicine, found that prolonged sedentary behaviour was associated with a 15- to 20-per-cent higher risk of death from any cause; a 15- to 20-per-cent higher risk of heart disease, death from heart disease, cancer, death from cancer; and as much as a 90 per cent increased risk of developing diabetes, said Alter.
And that was after adjusting for the effects of regular exercise.
“Avoiding sedentary time and getting regular exercise are both important for improving your health and survival,” said Alter. But engaging in 30 to 60 minutes of moderate to vigorous daily exercise does not mean it’s OK to then “sit on your rear” for the rest of the day.
The paper’s authors can’t say how much sitting time is too much — more research is needed to understand what represents a healthy balance between being sedentary and engaging in physical activity.
Not surprisingly, however, they found that negative health effects from prolonged sitting are even more pronounced among those who do little or no exercise.
Alter, a cardiologist, said public health messaging has long focused on encouraging Canadians to get daily exercise to promote good health — working out to strengthen the heart and circulatory system and to help prevent various cancers, including breast and colon cancer.
“We need to get sedentary behaviour on our radar and start talking about that, not just exercise,” Alter said.
In his practice, he encourages patients to stand for periods of time each day, because being fully upright burns twice as many calories as does sitting. It also helps to strengthen bones and muscles through weight-bearing gravity.
Couch potatoes could try getting up during TV commercials, or perhaps watch the last 15 minutes of a hockey game standing.
He also recommends that patients get up and walk around for a few minutes every half-hour during their waking hours.
“It’s about breaking the mould of our culture, which has had us going from hunters and gatherers to sitting all the time.”
“IT’S ABOUT BREAKING THE MOULD OF OUR CULTURE …” DR. DAVID ALTER