This is an odd coincidence. I'm seeing my doctor for this tomorrow. As a scientist, I'm big of reproducible, objective evidence, so I used 3 different types of SPO2 monitor (Galaxy Watch 5, Wellvu ring, and the Welvue wrist/ring combination. All 3 show the fluctuations, and 2 that I ran together match. I have printout data from both. No symptoms at any point, range 71-100%.

Check your blood pressure, if you havent already. Mine is just as nuts. Pulse ranges from 42 to 150+,
It's real, and you are not alone.

@kudzu Did you ever find out what is causing the O2 levels to drop? I have the exact same thing happening and I also have severe sleep apnea. My doctors don’t believe me about the oxygen levels. Years ago I went to the Heart Hospital because of shortness of breath and they found nothing. Recently they did a sleep study and said it was very bad. One doctor told me to check my O2 levels regularly, so I did. I woke up with a terrible headache, which is common for me, and my O2 level was in the 50s. I got my phone and recorded it from 66 to 90s. I was told to go to urgent care which I did and they didn’t believe me and said my machine was not accurate. I explained that the sleep clinic recorded very low levels too and she told me their machines were not accurate either. She told me that if my levels were that low I would die, which is my fear and why I don’t sleep. The emergency room nurse said I was a hypochondriac and sent me home. I got an appointment with my doctor and he agreed with her and canceled an overnight Oxygen study he had previously ordered which really sucks because now he doesn’t want to do anymore testing. I have a lot of issues and probably all related to no sleep and fluctuating O2 levels. I have lots of photos of low oxygen levels but that only confirmed to them that I am a hypochondriac, lol. My head hurts so bad at times that I can’t think straight and I suffer from confusion at times. Lots of problems sleeping even though I am extremely exhausted. I often worry that I will not wake up when I do sleep for a few minutes. I quit drinking because they said it could be the cause of my problems but I have not had a drop of alcohol for over 6-8 months and still have the exact same problems. I take blood pressure medicine but wonder if it was high because of the oxygen levels being off. I also have night terrors and often wake up to the sounds of explosions, gunshots inside my bedroom, bullets hitting my house, doors being smashed in and once my house broke in half, which was probably the most terrifying, lol. If I don’t wake up to an explosion it is usually to bring choked to death in my dream or me choking someone to death, but death is almost always the end result as I wake. I would really appreciate any insight you might have because I think all of my issues are related to a medical issue, I just don’t know what. I am not afraid of dying but would like to outlive my mother who needs me to survive.