Actually, if it’s a life or death matter (tsumego? ), suppressing the urge to breathe can be useful for a while… as long as you don’t pass out.
Thanks, very interesting. Just a quick remark that that was not my own explanation, but someone else’s that I found (I put the link) and wanted some expert perspective on - which you gave me.
Incidentally, Wim Hof would probably agree with that statement.