For adults 60 and older, every additional hour a day spent sitting is linked to a higher risk of disability, regardless of how much moderate exercise they get, according to a study.
The study by researchers with Northwestern Medicine is described as the first to show that 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, the researchers reported.
Among two 65-year-old women, one sedentary for 12 hours a day and another sedentary for 13 hours a day, the second is almost 46% more likely to be disabled, according to the study, which was published Feb. 19 on the website of the Journal of Physical Activity & Health.
This is the first time weve 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 in Chicago and lead author of the study, said in a news release. Being sedentary is not just a synonym for inadequate physical activity.
Disability, which affects more than 56 million Americans, is defined by limitations in ability to do basic activities such as eating, dressing or bathing oneself, getting in and out of bed and walking across a room. Disability increases the risk of hospitalization and institutionalization and is a leading source of healthcare costs, accounting for $1 in $4 spent, according to the news release.
Dunlop was surprised by the finding that being sedentary was almost as strong a risk factor for disability as lack of moderate or vigorous activity.
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 focused on a sample of 2,286 adults ages 60 and older from the National Health and Nutrition Examination Survey. It compared people in similar health with the same amount of moderate or vigorous activity. An example of moderate activity is walking briskly, as if you are late to an appointment.
The participants wore accelerometers from 2002 to 2005 to measure their sedentary time and moderate or vigorous physical activity. The accelerometer monitoring is significant because it is objective, the researchers noted. The older and heavier people are, the more they tend to overestimate their physical activity. Previous research indicated a relationship between sedentary behavior and disability but was based on self-reports and thus could not be verified.
Because the study examines data at one point in time, it does not definitively determine that sedentary behavior causes disability. It draws attention to the fact that this is a potential problem, said Dunlop, who is doing a longitudinal study on sedentary behavior and disability risk.
Studies with animals have shown immobility is a separate risk factor for negative effects on health. This is the first piece of objective evidence that corroborates the animal data, Dunlop said.
Study abstract: http://bit.ly/1jSKqlz