Sleep is good. Sleep is how I can do this day after day. The body rests and I awake with refreshed legs to do it again. But I've noticed a change in my sleeping habits. Besides sleeping longer than I had, (went from 6 or less to 8 or 9) I also find myself rotating through the night like a rotisserie. Quarter turn at a time 2 or 3 revolutions. I figure... whatever it is, it works.