By the way, having enough oxygen in the room plays an important part of a quality sleep, too! I forgot to point this out yesterday, but good thing I remembered it now. 😃
In my experience, I feel like the oxygen in my room isn't enough when I feel some sort of a "deafening silence" in the atmosphere, and like I am sinking or something. Also, sometimes when the oxygen isn't enough, I'm having nightmares.
So I guess for everyone who gets to read this, make sure there's enough air flowing inside the room.
Have a great day!