Yes, you're right, Bakunin. I do martial arts with weapons, and we have a lot of ex-karate people coming through our doors. They are usually 35-40 years old, and their bodies are now too buggered to do karate any more. I have mixed feelings about that. It's partly down to the macho over-enthusiasm of young men, partly down to poor instruction (the instruction in karate, from what I hear, seems very variable), and partly down to the nature of the art itself. But even then, I would draw a distinction between that and boxing.
And specifically with boxing, you are aiming blows at the head. There is simply no safe way in which to do that.