Recommended weekly physical activity doesn't fully protect from too much time sitting

People who meet recommended weekly physical activity guidelines are still at risk of developing chronic disease if they spend too much non-exercising time sitting, new research suggests. Peter Katzmarzyk, associate executive director for population and public health sciences at Pennington Biomedical Research Center in Baton Rouge, La., will discuss epidemiological data and other current findings about the effects of sedentary behavior on long-term health at the American Physiological Society's Integrative Biology of Exercise 7 meeting in Phoenix.

Studies show that spending excessive amounts of time sitting or watching television is linked with chronic health issues such as heart disease and type 2 diabetes. The American Heart Association recommends at least 150 minutes of moderate-intensity exercise each week. Habitual non-exercisers have an increased risk of premature death than people who are highly active. Data from the U.S. National Health and Nutrition Examination Survey show that women -- especially obese women -- spend more time sitting as they grow older. People of both genders with higher levels of education tend to be more sedentary, too.

"It appears that there are independent health effects associated with excessive sitting, and that even in people who are meeting the physical activity guidelines of 150 minutes per week, there are ill health effects associated with sitting excessively during the rest of the day," Katzmarzyk said.

Studies that explore the association between exercise and sedentary behavior consistently show that replacing sitting time with even light activity -- even though moderate-to-vigorous activity is preferred -- can have a positive effect on health in the long term.