“Over and above any considerations of performance for sports, exercise is the stimulus that returns our bodies to the conditions for which they were designed. Humans are not physically normal in the absence of hard physical effort. Exercise is not a thing we do to fix a problem— it is a thing we must do anyway, a thing without which there will always be problems. Exercise is the thing we must do to replicate the conditions under which our physiology was adapted, the conditions under which we are physically normal. In other words, exercise is substitute cave-man activity— the thing we need to make our bodies, and in fact our minds, normal in the 21st century. And merely normal, for most worthwhile humans, is not good enough.”
— Mark Rippetoe, Starting Strength
This paragraph really made an impact on my exercise philosophy. Recent research has shown that exercise combats depression as well or better than prescription drugs. But maybe the implied metaphor, exercise-as-a-drug, is wrong. Maybe this special kind of human behavior—good exercise—is integral to the human animal, like the other pillars of human normalcy: good nutrition, good sleep, good learning, good social interaction, etc. A person can survive without the support of any one of these pillars, but thrives with all of them intact. After all these years of using exercise as a kind of therapy, I’ve finally begun to think of good exercise as a necessary part of sane, healthy living.