> anxiety because you may wake up with night terrors after suffocating in your sleep.

I have SA and a history of "mild" nightmares going back decades. Nothing terrifying, but very uncomfortable such as snakes hiding everywhere, and recently other animals such as tigers. I can't prove it, but I believe these are subconscious efforts by your brain to scare you into breathing.

I mean, panic attacks where you hyperventilate are basically the drowning reflex going off. So given that a lot of the dreams in our case were literally suffocating (drowning, etc.), I'm pretty sure that some part of the brain gets awakened enough to realize something, if not exactly what.