I am a huge advocate of using pulse oximeters, which measure blood oxygen saturation levels, to help monitor how Covid is affecting one's lungs. A pulse oximeter may have even saved my life; when I caught Covid in fall 2020, I had no trouble breathing but my handy pulse oximeter told me that my measurements were at a level where I should seek medical attention, and physicians in my family told me to go immediately to Georgetown Hospital. Once there, they found significant pneumonia in my lungs, admitted me, treated me, and released me good as new (after a few weeks recovery).
One concern about pulse oximeters, however, has been that they may work less well on people with dark skin. Specifically, that they slightly overestimate blood saturation levels; that slight overestimation, however, can have significant consequences regarding medical attention and treatment.
