A Little Biochemistry of "Use It Or Lose It"
When exercise, mental and physical, improves your condition, this means that a great many changes are taking place in your cells. You are a machine composed of many, many machines; wear and tear in you is built of wear and tear at the level of cells and molecules. "Mice with (a) high spontaneous neurological activity, or subjected to (b) moderate exercise or (c) dietary supplemented with high doses of vitamin E from [showed] an increased survival and a retardation in the development of the neurological deficits associated to aging. During aging there was an increase in dysfunctional brain mitochondria, characterized by an increased content of oxidation products and by a diminished functional activity. ... In brain mitochondria, the activities of enzymes that are critical for mitochondrial function [decreased] progressively during aging. ... increased neurological activity, moderate exercise, and vitamin E supplementation, proved to be effective in increasing mice survival and neurological performances, along with a better mitochondrial function and a lower content of oxidation products." Use it or lose it.
Link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=17127368