Malarky. While physical fitness will help it is absolutely no substitute for letting you "do something stupid". You need to be able to walk, and you need to be prepared for the conditions you'll face, and you need to be able to keep track of where you are.

Sorry, as a fat guy who knows how to walk I just can't agree with this.. seen too many marathon runner types in the bush with this same attitude - they can't possibly get in trouble because they run daily and are in great shape.

While better physical conditioning will help you in any endeavor, it's NOT something to rely on to get you out of a situation. Do you need to be a marathon runner to hike? no. it's just walking. get out and do it. just don't be silly about it.