Old thread but I see the topic is an active discussion. In March of this year I had my 4th bout of covid. April 18th it progressed to pneumonia, empyema, a paralyzed diaphragm. Underwent two lung surgeries and have one scheduled in two weeks to address my diaphragm. My o2 levels fluctuate wildly. It will drop into the mid to low 80s and go back to 94ish which is my normal baseline now. It's very frustrating because if you follow medical advice, by the time you get to the hospital the numbers will return to normal and yes, the ER doctors will treat you like you're overreacting and it's no big deal, meanwhile, you know what you just went through. Your body doesn't lie to you.