More than half of the average person’s day is spent being sedentary — sitting, watching television or working at a computer. And if you are a student, that number is likely to be higher.
According to a study released yesterday in the Annals of Internal Medicine, the health-enhancing benefits of physical activity alone may not be enough to reduce the risk of disease. In an analysis that pooled data from 41 international studies, Toronto researchers 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. And that was after adjusting for the effects of regular exercise.
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.
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. Now, we need to get sedentary behaviour on the radar and start talking about that, not just exercise.
Dr. David Alter, a senior scientist at the Toronto Rehabilitation Institute and one of the lead researchers on the article, encourages people 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 people get up and walk around for a few minutes every half-hour during their waking hours.