Guys! I just signed up for the CN Tower climb with a bunch of guys here at work and I feel like this is the biggest mistake of my life. The CN tower is 144 flights of stairs and it is happening in 11 days. What kind of stuff should I do to prepare for it so I don't hurt myself? I have access to a gym that has a stepmill, so I was thinking of doing that and trying to do 144 floors on that for the 11 days. I don't normally work out, but I do some cardio (elliptical) occasionally.