Men should walk at a speed of five km an hour or more to enjoy a long life.

'Interestingly, no men with walking speeds of 1.36 m/s or above had contact with the grim reaper. The results support our theory that faster speeds are protective against mortality, because fast walkers can maintain a safe distance from the grim reaper,' Dr Danijela Gnjidic, who co-authored the study said.
Source-Medindia