I just realized something extremely cool. You know how when you walk up a fairly long flight of stairs, you feel a bit out of breath at the top? (It's not just me, right?) I mean, it's not like I was ever clasping my chest and sucking air, but even when I was training for the Ironman, I regularly felt winded by stairs. I knew I wasn't "out of shape," so I just figured it was a fact of life.
Well, I just heard the cell phone ring, realized it was two floors down, sprinted down there, answered it, and then jogged back up, talking to the caller the whole time. Not even thinking about it, and not even a little bit out of breath. This is on almost zero "cardio" training for the past three months.
Wrap that in your low-fat tortilla.