Study Links More Time Spent Sitting to Higher Risk of Death

July 23, 2010

A new study from American Cancer Society researchers finds it’s not just how much physical activity you get, but how much time you spend sitting that can affect your risk of death.

Researchers say time spent sitting was independently associated with total mortality, regardless of physical activity level. They conclude that public health messages should promote both being physically active and reducing time spent sitting. The study appears early online in the American Journal of Epidemiology.

To explore the association between sitting time and mortality, researchers examined the amount of time spent sitting and physical activity in relation to mortality between 1993 and 2006. They found that more leisure time spent sitting was associated with higher risk of mortality, particularly in women. Women who reported more than six hours per day of sitting were 37 percent more likely to die during the time period studied than those who sat fewer than 3 hours a day. Men who sat more than 6 hours a day were 18 percent more likely to die than those who sat fewer than 3 hours per day. The association remained virtually unchanged after adjusting for physical activity level. Associations were stronger for cardiovascular disease mortality than for cancer mortality.

When combined with a lack of physical activity, the association was even stronger. Women and men who both sat more and were less physically were 94% and 48% more likely, respectively, to die compared with those who reported sitting the least and being most active.

“Several factors could explain the positive association between time spent sitting and higher all-cause death rates,” said Dr. Patel. “Prolonged time spent sitting, independent of physical activity, has been shown to have important metabolic consequences, and may influence things like triglycerides, high density lipoprotein, cholesterol, fasting plasma glucose, resting blood pressure, and leptin, which are biomarkers of obesity and cardiovascular and other chronic diseases.”

Article: “Leisure Time Spent Sitting in Relation to Total Mortality in a Prospective Cohort of US Adults.” Alpa V. Patel, Leslie Bernstein, Anusila Deka, Heather Spencer Feigelson, Peter T. Campbell, 5 Susan M. Gapstur, Graham A. Colditz, and Michael J. Thun. Am J Epid Published online July 22, 2010 (DOI: 10.1093/aje/kwq155)

More info: American Cancer Society news