Being sedentary is just as deadly as smoking, series finds

Getty Images photo by George Doyle

Physical inactivity is such a problem worldwide it has become as deadly as smoking, a series of studies has found. Lack of exercise causes about one in 10 premature deaths worldwide, in large part because it contributes to heart disease, Type 2 diabetes, breast cancer and colon cancer.

"If physical inactivity could be reduced by just 10 percent, it could avert some 533,000 deaths a year; if reduced by 25 percent, 1.3 million deaths could be prevented," reports Alice Park for Time Healthland.

In a study published in the journal Lancet, researchers "calculated something called a population attributable fraction (PAF), a measure of the contribution of risk factors like physical inactivity to diseases such as heart disease or diabetes, and even risk of death," Park reports. That calculation indicated how many incidences of disease could have been prevented if people started exercising like they should. PAFs were calculated for 123 countries and showed overall that physical inactivity is responsible for 6 percent of heart disease, 7 percent of Type 2 diabetes and 10 percent of breast and colon cancers.

The numbers also showed people living in the Americas have the most physically inactive populations — 43 percent of people don't get enough exercise — while people who live in Southeast Asia are the most active. The Americas' reliance on cars and other vehicles is considered a major factor in their sedentary lifestyles, with just 4 percent of people in the U.S. walking to work and fewer than 2 percent using a bicycle to commute.

Experts say sufficient physical activity is the equivalent of 150 minutes of moderate exercise a week, which could mean 30 minutes of fast walking five times a week.

Another paper in the series pointed to steps people and communities can take to be more active: using signs to suggest taking the stairs rather than the elevator, or free exercise classes at public parks, for example. Maintaining streets and improving lighting can raise activity levels by 50 percent, some studies show. Researchers also discussed an effort in Bogotá, Colombia, where some city streets are closed to cars and vehicles on Sunday mornings and public holidays. Each week, about 1 million people show up to exercise. The effort has spread to Kentucky and been dubbed Second Sunday Kentucky.

Some experts took issue with the comparison with smoking, since "even if smoking and inactivity kill the same number of people, far fewer people smoke than are sedentary, making tobacco more risky to the individual," Park reports. (Read more)