It has been said that exercise is the closest thing there is to a miracle cure. “All the evidence suggests small amounts of regular exercise (five times a week for 30 minutes each time for adults) brings dramatic benefits.” But why is it so awesome? In a really general sense? What makes it such a wonder drug?
Exercising at the right intensity +The right intensity being the Goldilocks zone: enough to provoke adaption, not enough to injure. is biologically “normalizing,” pushing systems to work the way they are supposed to work. Biology is all about clever homeostatic mechanisms [Wikipedia] that nudge tissue state back to average. Those systems all rely on negative feedback loops based on molecular signalling (hormonal, neurological, etc), and exercise produces a lot of stimulation … raw “data” to feed into the negative feedback loops, which is normalizing.
It’s not a universal principle, and exercise cannot normalize everything. +Many specific pathological processes are a freight train that will not be stopped by exercise. Consider a blatant example like a tumor, or something a little less obvious like multiple sclerosis. But it does stimulate an incredible array of adaptive and homeostatic mechanisms — way more than any other kind of treatment.