Exercise as medicine has been a philosophy that has been gaining traction. Here is a new article and runners world confirming that running that only makes you feel better but adds to your longevity even factoring in early deaths that  may occur with cardiac events etc. Staying  healthy on your feet as part of that equation.

http://www.runnersworld.com/health-injuries/1-hour-of-running-adds-7-hours-of-life