That's what I did today - joining the manly men of the entertainment department who are all lifting weights. Thankfully, I avoid their grunting because the cardio room is separate. I watched the Price is Right today; there was only one other exerciser in there, using the elliptical, so it was nice. I ran about 3 miles at a 9:40/mile pace. I felt pretty good, but I don't think I would run more than 40 minutes on a treadmill. I love putting my unifrom back on when I'm already all sweaty - but hey, it's just going to get sweaty from work anyway.