"My suspicion is that the effects of running are no extraordinary at all, but quite ordinary. It is the other states, all other feelings, that are peculiar, for they are an abnegation of the way you and I are intended to feel. As runners, I think we reach directly back along the endless chain of history. We experience what we would have felt had we lived ten thousand years ago, eating fruits, nuts, and vegetables and keeping our hearts and lungs and muscles fit by constant movement."

-The Complete Book of Running by James Fixx