^I've been going back and forth about walking because of the temperatures. On the one hand, I warm up after a while. On the other hand, I didn't really warm up yesterday when I went for it.
I usually try to leave my knife bag at work when I want to walk, because that thing is a heavy mofo that markedly slows me down, but the extra effort of carrying it while going at a quick pace is handy for making me sweat.
As I walked the other day I wondered if runners start up at home so they're already warm when they get out into that frigid air.