Well - in hyperspace you may be able to coalesce with any and all particles in the universe on a quantum level... so it may just be possible to "breathe" in some form or another In standard space, of course not :afro:
Your body is safely breathing in the physical realm, while your consciousness, which doesn't need to breath, is traveling through the stellar complexities which are hyperspace!
Sometimes the transition stage leaves me feeling like I can't breathe, or as if I have to tell myself to breathe. When one is actually broken through into hyperspace one has no way of knowing what's going on physically, but there is a few moments where one is halfway between the realms, at least for me and sometimes I am frightened that my body won't continue respiration. I've been told numerous times that I can just ignore it because my body will take over, but while tripping that hard it is difficult to remember things that one has been told.
I was reading a book on meditation that said the deeper you meditate the slower your breathing will get. Like first 5 breaths a minute, then 3 breaths a minute, then 2, until you come to the point where it is like 1 breath per minute or less. I know on mushrooms I have been in such a deep state that Ill come out of it and suck in a breathe like its my last breathe on earth. And I will realize I have taken a single breath in like 3 whole minutes. Its like your living off pure experience. Your body will take over if it needs to, but like you said it is hard to remember things like that. It could be pretty frightening during a full on breakthrough. Usually though I am so engulfed in the transition to the other world I don't even think about my body until Im back. Guess it depends on the situation.
Tit is so aggravating but i write a whole story sbout what i meant to talk about and when i go to post it thr browser fails and i can never explain what i wanted to. Take my word for it though it was really poignant