Our bodies evolved to enable prolonged exercise, which is quite absent from our modern lifestyle. We have used technology to create artificial environments, but not environments to which our bodies are adapted. My preferred form of exercise (one which, unlike organized sports, is consistent with my general clumsiness) is walking.
Walking uses up blood glucose, and it does so happily: you can relax, you can notice things about trees and birds and people, and it doesn’t cost anything, except for some cheap shoes. And it is something that most people (including most diabetics) can do. There is no minimum amount of walking less than which is useless. And it brings lots of oxygen into your alveoli. Once in a while I even break into a jog, though not for very far.
Of course, unexpected problems can arise. For me, it is the fact that in rural Oklahoma, nearly everyone drives a pickup truck that belches out huge billows of fumes. Even the new ones. I wonder if part of the standard detailing of new trucks in rural Oklahoma is to attach a little spigot that sprays fumes into the air directly from the fuel tank. (I just made that up. That doesn’t mean it isn’t true.) Almost every man in rural Oklahoma is so worried about his manhood that he feels he has to compensate for whatever he has to compensate for by getting a big truck (sometimes with truck balls). (I didn’t make that part up.) And of course they leave a stream of fumes that the wind blows into my alveoli for an entire block. If there is one truck on the road, it will find me and pickle me in its hydrocarbons. And of course almost everybody lets their dogs run loose. The dogs would probably eat me if I were not glazed with petroleum derivatives.
Walking creates a positive feedback loop. The more walking, the more capacity for walking.
Walking allows me to notice things about trees. What I did not expect was that my observations would become useful. In 2006, I started making maps of the trees along my walking route, and writing down the day in spring when each tree burst its buds. It turns out that, from 2008 to the present, the trees have been opening their buds about two days earlier each year, a rather striking record of global warming. A research presentation at the world meeting of scientists who study phenology came out of these observations.
By pursuing a healthy lifestyle, I make myself a better participant in the health of the planet, create a positive feedback loop for even greater health, and open myself up to serendipity.