I was reading through a thread on Dennis Chambers' one-hand break where one of the posts was:
I saw Dennis in clinic. He did a very intense solo and was not breathing hard at all. He bases a lot of his endurance on correct breathing - not as easy as you would think. Play the hardest song you know and check out your breathing at the end.
I remember reading somewhere that Dave Dicenso talks about proper breathing techniques in his clinics.
Personally, I don't end up breathing hard at the end of a difficult song. I'm curious what info any info you may have on this.