The most interesting part of his interviews (there are a number on his youtube channel) is one in which he taught a group of people to juggle. Less than half actually mastered the act, but his point was that the parts of the brain that were stimulated and thus protected from atrophy were identical in the entire group! In other words, just by trying to master a new activity, important parts of the brain are activated and stimulated whether or not you actually "master" the activity.
Your body, and your mind don't really care about mastery, or accomplishment in the eyes of others; the point is that you continue to get up and try. Forever; not just when you are in your teens, or twenties- forever!
If we stop moving, we essentially DIE. So, make movement, mental and physical effort, real play and real physical work part of your life. Your life will be immeasurably richer and happier for it!
