Leisure-time physical activity is associated with longer life expectancy, even at relatively low levels of activity and regardless of body weight, according to a study by a team of researchers led by the National Cancer Institute (NCI), part of the National Institutes of Health. The study, which found that people who engaged in leisure-time physical activity had life expectancy gains of as much as 4.5 years, appeared Nov. 6, 2012, in PLoS Medicine 
.
In order to determine the number of years of life gained from leisure-time physical activity in adulthood, which translates directly to an increase in life expectancy, researchers examined data on more than 650,000 adults. These people, mostly age 40 and older, took part in one of six population-based studies that were designed to evaluate various aspects of cancer risk.
The U.S. Department of Health and Human Services, the parent agency of NIH, recommends that adults ages 18 to 64 engage in regular aerobic physical activity for 2.5 hours at moderate intensity—or 1.25 hours at vigorous intensity—each week. Moderate activities are those during which a person could talk but not sing. Vigorous activities are those during which a person could say only a few words without stopping for breath.
After accounting for other factors that could affect life expectancy, such as socioeconomic status, the researchers found that life expectancy was 3.4 years longer for people who reported they got the recommend level of physical activity. People who reported leisure-time physical activity at twice the recommended level gained 4.2 years of life. In general, more physical activity corresponded to longer life expectancy.
