I used to believe when it came to exercise, more was always more.Especially for a multisport athlete who is running, backpacking, mountaineering and wanting to be ALWAYS READY TO ROLL at a moment's notice.Also, as I cruised toward 50, I felt like I needed to work harder just to maintain a certain level of performance.But this summer, I got tired of being exhausted.Tired of grinding through my day job.Tired of feeling irritated with every little thing. (Like I would knock over a can of Seltzer...