Even as a mouth breather, you're getting at least some of the 02. As you breathe in, you're breathing through both your nose and your mouth. Unless you hold your nose closed, your'll get 02 through your nose.

I too am a mouth breather. I have allergies so I can't always wear a cannula in my nose, so I will often just tighten the cannula around my mouth instead. Or I let the cannula hang from one ear and rest on my pillow when I sleep on my side letting the air hit down by my mouth.. No way would I ever tape my mouth closed, that would create way to much anxiety. Good luck. And I hope you find a comfortable way to sleep.

I wear the nasil cannula for oxygen at night. I wake up with my mouth open I'm dizzy and lightheaded in the morning. It scares me. I sleep 6 to 7 hours straight no problem until I wake up.

Hi Robin, are you talking about sleeping with Oxygen?

And your casual is across the room lol I do it about once a week