I agree on the perspective that the muscular system is a secretory organ that constantly secrete molecules to the rest of the body. Muscles are highly metabolic, easily targeted, very responsive to interventions and highly adaptable to the activity they perform.
With exercise intervention we can influence what kind of substances the muscles secrete to the rest of the body. One can say that in, a very imprecise statement, that when exercising and building healthy muscles you reap benefits of whole-body rejuvenation, in a way that is similar to what researchers try to do with parabiosis, plasma exchange, plasma dilution etc. But the thing with exercise is that we know it works and that it improves health span, and it is available to almost all people.
Good points re exercise, however, there are many exercise sites / publications. Likely most on this site also exercise, but this site covers items, re anti-aging, etc., that are not adequately covered elsewhere.
On the other hand, little mention on this site re diet, nor food quality, nor water quality. I'm sure many use bottled water of one kind or another, but one absorbs more chemicals from washing / bathing, than drinking.
Very possible for the chlorine, fluorides, etc. in water could counter some of the anti-aging protocols.