Huge Study Determines the Pace of Cardio that Extends Life the Most

From Nate Silver's blog, the data scientist with the best record of election predictions, a meta-analysis of the data shows that jogging is best, walking is ok, and hard running is out. - A

If we take this research at face value, we learn a few things. First, some exercise reduces your risk of death. Second, the optimal walking/jogging exercise is light to moderate jogging. The optimal speed is between 5 and 7 mph, and if you do 25 minutes about three times a week, you’re all set. Nothing in the data suggests that running more — farther, or faster — will do more to lower your risk of death.

http://fivethirtyeight.com/features/whats-the-optimal-speed-for-exercise/