I also do not have obstructive sleep apnea. I have been put on O2 at night mostly normal but randomly it drops down to 88 -86 also noticed that pulse rate will drop down to 47, told my doctor she says my heart is GREAT and nothing is wrong there. I done the pulmonary test and it is fine. The only drugs I am currently taking are pravastatin so I don't think that's the problem. I personal think I have a issue with O2 dropping more during the day then the night. I agree I think something more along the lines central apnea all the time. Or maybe long covid. If anyone has any recommended tests please let me know.