Indeed. "Thanks" to be being a frequent flier in a global company I got Covid already in March 2020 and was constantly checking my oxy values. Never got below 91, but if they had hit 90 I was told to take an ambulance right away.

For reference, I have what my doc calls "emphysema light" and was just in the local doc-in-a-box for my first go-round of COVID. My blood O2 was 97 and I felt short of breath. 80 sounds like I wouldn't be moving under my own power.