WEDNESDAY, July 28 (HealthDay News) -- People who sit for six or more hours in their leisure time daily face a higher risk of mortality, with time spent sitting associated with mortality regardless of physical activity level, according to research published online July 22 in the American Journal of Epidemiology.

Alpa V. Patel, Ph.D., of the American Cancer Society in Atlanta, and colleagues analyzed data from 123,216 men and women from a prospective cohort study of cancer incidence and mortality. Subjects reported the time they spent sitting or engaging in physical activity.

The researchers found that spending at least six hours seated per day, compared to less than three hours, was associated with a higher risk of mortality in women (relative risk, 1.34) and men (relative risk, 1.17). Sitting for six hours or more daily, in combination with getting less than 24.5 metabolic equivalent-hours of physical activity per week, was associated with relative risks of 1.94 in women and 1.48 in men, compared to those with the least amount of sitting and most physical activity. The time spent sitting was associated with mortality regardless of the participant's level of physical activity. The researchers found the strongest associations for cardiovascular disease mortality.

"Public health messages and guidelines should be refined to include reducing time spent sitting in addition to promoting physical activity. Because a sizeable fraction of the population spends much of their time sitting, it is beneficial to encourage sedentary individuals to stand up and walk around as well as to reach optimal levels of physical activity," the authors conclude.

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