This story about COVID-19 patients who seem like they're doing okay, but still have what, by normal standards, are distressingly low blood oxygen levels matched my own experience. https://www.statnews.com/2020/04/08/doctors-say-ventilators-overused-for-covid-19/

By Day 10, all of my symptoms were gone except occasional shortness of breath. But the strange thing is, if anything, my blood oxygen levels began to get worse. Maybe half the time, the readings would start out in the low 90s—95 and above is normal—and gradually move up.

One day when I felt particularly short of breath, my blood oxygen reading started out at 74, and then moved up to 97 within a few minutes. Another started out at 88. I also had readings that started at 95, and then *fell* to 82. This was three weeks after my symptoms began!

My doctor friends thought my oximeter had to be off, but my wife, who recovered before me, was getting 97s and 98s right away whenever we checked her. It wasn't until the last three days that I've started to get similarly good readings and no bad readings anymore.

The point is that there's still a lot we don't know about COVID-19. I was briefly getting blood oxygen readings that suggested I should be in extreme distress even when I didn't feel like I was having much trouble breathing. Doctors don't seem to know what to make of this.

My doctor friends—who are really smart, and have been giving me great advice!—just couldn't imagine that I was still getting bad blood oxygen readings, or that those readings were real.

But I think they definitely were. My oximeter wasn't broken. I'm getting good readings now.