Well, I used to be a pretty active guy. In my day I was a competitive rock climber, cyclist and swimmer. Played football and rugby, too. Becoming an Assistant Professor and father has put most of that on hold. But once the kids are a bit older and I get tenure (i.e., can afford to take a few weekends off?), then look out! I'm going to be the coolest 40-something Professor that anybody knows! Seriously, my active hobbies have always been central to my identity and a big part of the reason I have remained healthy. Dropping them all cold turkey is not a good thing, but I WILL get back on the bike and the sharp end of a rope.