I have a slightly different take on this: IMHO being as physically fit as reasonably possible is a no-brainer. I just wish I could make myself live up to that standard.
OTOH as I look back on my adventures and misadventures in the wild or on the ocean I have to admit that every misadventure and every injury would probably have been avoided by being slothful, lazy, and cowardly! When I "cowboy up" (forgive me, Chris.. I've been a wannabe)I get hurt.
If ever again in a survival situation I hope to be timid, not bold. To carry much less than I think I can manage. To move more slowly, to push less, to risk less, to cut/chop more deliberately..to get warm and dry much sooner. And so on. The others can be Superman. I'll be Clark Kent.