When we had the big blackout last August (while I was at work), I had to walk down 56 flights of stairs and it took me just under half an hour, plus the next day my calves felt like they were on fire. Yesterday the building decided it was time for another emergency evacuation test and I made sure to look at my watch before I left. Got down the stairs in 17 minutes and today the calves are tingling a bit, but not terribly uncomfortable. This really made me feel good, because my weight hasn't changed much in that six months (down about 10lbs. after losing over 90lbs. the first year), so I was getting a wee bit discouraged. But now I can tell I'm in better shape than six months ago, so that's non-scale progress and I find it a great motivational tool to keep going.