I used to run when I was on the wrestling team in HS and in the air force. But I was never fast, nothing near a 4.48 pace even in my prime. I switched to walking years ago. My doctor would like me to go even lower impact, but I do not have easy access to a pool. I am glad I gave up running, I am seeing a lot of friends, family, and acquaintances runners in my age range (I am 58) getting hip and or knee replacements.