The Longer You Sit the Shorter You Live

(July 23, 2010) - Sitting around could be life threatening. A new study from American Cancer Society researchers finds it's not just how much physical activity you get (Read about "Getting Started on Fitness"), 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.

Increasing obesity levels (Read about "Obesity") in the United States are widely predicted to have major public health consequences. A growing epidemic of overweight and obesity has been attributed in part to reduced overall physical activity. And while several studies support a link between sitting time and obesity, type 2 diabetes, cardiovascular disease risk factors (Read about "Diabetes" "Heart Risks"), and unhealthy dietary patterns in children and adults, very few studies have examined time spent sitting in relation to total mortality

To explore the association between sitting time and mortality, researchers led by Alpa Patel, Ph.D. analyzed survey responses from 123,216 individuals (53,440 men and 69,776 women) who had no history of cancer, heart attack, stroke, or emphysema/other lung disease (Read about "Cancer: What It Is" "Heart Attack" "Stroke" "Chronic Obstructive Pulmonary Disease") enrolled in the American Cancer Society's Cancer Prevention II study in 1992. They 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 percent and 48 percent more likely, respectively, to die compared with those who reported sitting the least and being most active.