I guess I must have the bi-Pap, cause I know it adjusts when I exhale.

I began using it again a couple of months ago (after an 18 month hiatus), but was having difficulty getting the mask to seal. Had it tested and mailed it off to the factory to get the settings adjusted -- it was like being blasted in a wind tunnel! Using a loaner right now.

I use the full mask (nose/mouth). I do quit breathing a lot and for extended periods (according to a recent blood-ox test); however, I really don't notice a huge difference in alertness/energy level upon waking between sleeping with or without it. But, if I use the CPAP consistently, the dark circles under my eyes fade nicely. Also, I think I have fewer body aches.

Are you recovered from your surgery? Sorry you weren't feeling well and missed the GTG.

Sweet dreams!