I was diagnosed with complex sleep apnea a few years ago with 75 Apneas per hour. I started cpap but have very strange sleeping patterns since I spend 20+ hours a day in bed. Medicare took away my machine after three months because I missed their min sleep per day by four minutes. I've decided to try again and just did the study so should get machine in couple days. O2 was 89 so I think I have to have oxygen. I hate wearing the mask!