(HealthDay News) — In the United States, reducing sedentary behaviors, including sitting and television viewing, may result in an increase in life expectancy, according to a study published online July 9 in BMJ Open.

Peter T. Katzmarzyk, Ph.D., from Louisiana State University in Baton Rouge, and I-Min Lee, M.B.B.S., M.P.H., Sc.D., from Brigham and Women’s Hospital in Boston, used a prevalence-based cause-deleted life table analysis to examine the impact of sitting and television viewing on life expectancy in the United States.

The researchers found that reducing excessive sitting to less than three hours per day and reducing excessive television viewing to less than two hours per day would result in an estimated gain in life expectancy of 2.00 and 1.38 years, respectively, in the U.S. population. From a sensitivity analysis that involved simultaneously varying the estimates of relative risk and prevalence of television viewing, the lower and upper bounds of the 95 percent confidence interval were 1.39 and 2.69 years for sitting and 0.48 and 2.51 years for television viewing.

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“In conclusion, the results of this study indicate that extended sitting time and television viewing may have the potential to reduce life expectancy in the United States,” the authors write. “Given that the results from objective monitoring of sedentary time in the National Health and Nutrition Examination Survey [have] indicated that adults spend an average of 55 percent of their day engaged in sedentary pursuits, a significant shift in behavior change at the population level is required to make demonstrable improvements in life expectancy.”

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