Very thought-provoking commentaries, and instead of duplicating his thoughts, I'll just refer you there. I particularly like where he writes,
Time spent walking, then, is utterly free. It’s time you would have spent dead.(He reasons that for about every minute you walk you live about three minutes longer).
Of course, none of this applies to you, does it? I'm sure that the weather where you live is rainier than Seattle. Or that places you have to get to are farther apart than in this west coast city. Or that you get a lot less sunlight than winters above the 45th parallel.