Scafool, in contrast to that is the story of the doomed SAS team in Iraq during the Gulf War-one of the members, after being compromised & using their E&E plan, was found dead in the desert, only a few miles from the border of Turkey, where he was headed. They estimate he ran roughly 127 miles I believe, in a couple of days. He died, IIRC, of heart failure-but, he ran for almost 2 days straight.
Again, this is a rare example-I think we all benefit by being fit. Every little thing we do that increases our chances, is good. Wearing a seatbelt, eating right, making the right contacts, having good gear-ALL of it is prior planning. And, I am sure we all know the 5 P's, right?