Between the two of them, I'd always manage to miss sleep. Eventually, I'm going to be tired enough and just HAVE to sleep. With exercise, there's no guarantee of getting to a point where I just have to cycle/dance/walk/spin. I've spent more years not regularly exercising than years I have, so it's my keeper. I'll actually get back of bed if I remember I skipped workout, just to sneak something in quickly. Consistancy is everything for me, especially since the lack of sleep means lack of good food choices too often.

Hope I get caught up soon as well!