Author Affiliations

• Professor of Medicine, Epidemiology, and International Health (Human Nutrition), Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland.
• Correspondence to Dr. Lawrence J. Appel, Johns Hopkins Medical Institutions, 2024 East Monument Street, Suite 2-645, Baltimore, MD 21205-2223. Phone: 410-955-4156; Fax: 410-955-0476;

Sitting daily for less than 3 hours and watching TV for less than2 hours extends life expectancy by an estimated 1 to 2 years.

Adverse effects of sedentary behaviors on health outcomes are well known, but what are the effects on life expectancy? Investigators used data from five prospective cohort studies and from the National Health and Nutrition Examination Survey (NHANES) to estimate the effect of sitting and television viewing on life expectancy at birth in the U.S. population.