Leisure Time Spent Sitting Could Shorten Life

Researchers at the American Cancer Society (ACS; Atlanta, GA, USA) conducted a large prospective study of U.S. adults enrolled by the ACS to examine leisure time spent sitting and physical activity in relation to mortality. Time spent sitting and physical activity were queried by questionnaire on 53,440 men and 69,776 women who were disease free at enrollment. In all, the researchers identified 11,307 deaths in men and 7,923 deaths in women enrolled during the 14-year follow-up period.

The results showed that longer sitting time is related to higher mortality risks, especially in women. Women reportedly sitting more than six hours a day had 37% more chances of dying during the considered period than women who sat less than three hours a day. As for men, those who sat more than six hours a day were 18% more likely to die than those sitting less than three hours a day were. After adding the individuals' physical activity level to this data, the results remained proportional: women and men who sat more and had little or no physical activity had 94% and 48% more chance of dying (respectively), compared to those that sat less and were more active. The time spent sitting was independently associated with total mortality, regardless of physical activity level. The study was published in the July 22, 2010, issue of the American Journal of Epidemiology.

"Several factors could explain the positive association between [the amount of] time spent sitting and higher all-cause death rates,” said lead author Alpa Patel, Ph.D., an epidemiologist at the ACS. "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.”

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American Cancer Society