A study indicates that people who spend more time being physically active spend more time on this earth. At the National Institutes of Health, Steven Moore looked at life expectancy and physical activity in more than 650,000 people. Moore found those who did only a little still gained a lot:

"Even a very low level of activity, equivalent to about 10 minutes of walking per day, was associated with a gain of almost two years of life expectancy, regardless of body weight level."

On the high end in his study, those who did the equivalent of about 45 minutes or more of walking lived about four years longer than those who were not active.

The study was in the journal PLoS Medicine.
Source: www.hhs.gov