@mistibfaith YES! I thought i was getting dementia! Pulmonologist believes the oximeter is faulty. The watch too! Last year at the suggestion of a friend I have oxygen at night. The sleep study didn't show apnea, but at altitude my O2 was at 88. Still swings wildly, but not with oxygen. In the past year I pushed to find out and am still learning! I learned I have a PFO (aka hole in heart), had a stroke years ago ( Dr's thought it was a concussion earlier), lung nodules, and have SVTs. The Pulmonologist still says its my heart and the cardiologist says its my lungs. Chat GPT says I need to do lung exercises for breathing. The last test i begged for was a CPET. It claims its the heart not beating fast enough to keep up with my oxygen needs. Over the year of my testing, My osteoporosis and cholesterol has gotten worse. My pthrp test was high so i had a PET scan which came back negative. I am still researching. I will continue to do the work of a doctor as we all know they can't possibly spend the amount of time on your health as you can. Mayo clinic is possibly in my future.