Hello @ih60, Welcome to Connect. There is a correlation between sleep apnea and oxygen levels. Here is an article on the topic.

-- Sleep Apnea Diagnosis and Oxygen Desaturation Effects:
https://www.verywellhealth.com/sleep-apnea-and-oxygen-desaturation-3014875
I was diagnosed with obstructive sleep apnea a few years ago and I also was not aware that I had sleep apnea. I had a sleep study done at Mayo Clinic after a conversation with a cardiologist on a different problem. I mentioned I snored a lot and after a few more questions, he suggested a sleep study which determined I did have obstructive sleep apnea. It took awhile before the CPAP treatment made a noticeable difference. I do notice that I feel more refreshed after a good nights sleep now.

Have you discussed getting a sleep study appointment with your doctor or care team?