Before i starting using a CPAP machine, i was sleeping with my friend in his room. He had the windows and door shut. I felt stuffy and i would hyperventilate and i could not fall asleep. And same thing happened when i am at home.
Now i am using a CPAP machine. And i don’t have that feeling anymore. I can sleep well in a room with closed door and windows.
I think the reason may be, i was sensitive to oxygen or carbon dioxide level before the CPAP treatment, because my blood oxygen level was low in the first place. Anyone has the same experience? In the close room, carbon dioxide level would be a bit higher than a well-ventilated room.