TLDR 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

TLDR 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.