I get so confused with 02 and when should it be used I get conflicting answers I am on 02 for sleep and exertion. This couple months has been tough for me. Been prednisone and Sat ended up in ER with excasberation. I have noticed my Sats are dropping faster and I don't have that much breathing power to do much. When up and moving I drop to 88-89 then when I sit for a bit it goes back to 92-93. My question is what is an ok numbering does it help you with breathing? It seems like around 95 is good for me but don't want over use 02. Should I only use 02 if I go below 90.? I have enphyzema so worry about retaining 02. When I went ER cause couldn't get air my 02 was 96 but HR was out whack & I could hardly talk. They didn't put me on 02 because my 02 was fine. Then after some treatments and IV salmetrol my 02 dropped to 88 and they put 02 on. They took it off to check and went back so they put it back on. I don't understand how my Saturation goes up and down so much. Thanks for any input or help.