Stephen, you kinda have to train yourself to know they are there. About after an hour the only sensors I did feel were the Leg ones, my chin, and the nose/mouth sensor.
As Corrine said, ALL vitals are monitored.
Corrine, It was a hard night, the technician said I did REM a lot. Didn't feel like it... Felt like I was up a lot...
I sent a picture to my lover, and it scared them... Not my intentions. Just wanted them to understand this is what I went through.