If you strict yourself to a bber life style, and I am not talking about drugs, one can become a very functional (physicaly speaking) person. Strengthning your body gives you immense physical possibilities, because a stable basis was created, whther you want to box, swim, ride, etc, etc. Then, it also comes the cognitive aspect, that is the search for the best information about nutrition, training, etc, that can be very valuable to avoid some diseases for instance. Competitive bbing, now that's another completely different game...