Each extra hour of sitting after 60 doubles disability risk

No matter how much moderate exercise you get, a new study suggest that if you're 60 and older, every additional hour a day you spend sitting is linked to doubling the risk of being disabled.

The Northwestern Medicine study is the first to show sedentary behavior is its own risk factor for disability, separate from lack of moderate vigorous physical activity. In fact, sedentary behavior is almost as strong a risk factor for disability as lack of moderate exercise.

If there are two 65-year-old women, one sedentary for 12 hours a day and another sedentary for 13 hours a day, the second one is 50 percent more likely to be disabled, the study found.

"This is the first time we've shown sedentary behavior was related to increased disability regardless of the amount of moderate exercise," Dorothy Dunlop, professor of medicine at Northwestern University Feinberg School of Medicine and lead author of the study, said.

"Being sedentary is not just a synonym for inadequate physical activity," she said.

The finding -- that being sedentary was almost as strong a risk factor for disability as lack of moderate vigorous activity -- surprised Dunlop.

"It means older adults need to reduce the amount of time they spend sitting, whether in front of the TV or at the computer, regardless of their participation in moderate or vigorous activity," she said.

The study is set to be published in the Journal of Physical Activity and Health.