Adaptation

I have noticed one thing though, after I was able to ride to the rest stop point with this group where I had sworn to myself that I would not attempt to ride back with them, my body seemed to adapt to this new load. After the break (5-10 minutes) where I might have a couple fig newtons or a gu gel, I would go back with the group, and it would be easier than on the way was (and wind wasn't a factor, I actually like it when there is a head wind because it slows them down some) I always wondered why your body adjusts/adapts this way.

btw, there are a couple other 50+ guys in this group.