I was once told a story by my Sensei, now I don;t know the whole thing so i'll tell you in brief. Some cocky dude was annoying a really top ranking Japanese Sensei (this is in Japan), the cocky dude wasn't a beginner mind.... Anyhoo, he was prancing around and showing off so much that the Sensei hit a certain point (on purpose) on the dude's men that actually burst his ear drums (something to do with air pressure in the men). Ever since the dude calmed down and drilled holes in the side of his men so that it couldn't happen again. So yeah, It can affect your hearing...