On Thursday, April 9, 2020 at 6:32:47 PM UTC-4, Duster wrote:

You can test this pretty easily, of course.

Testing is good. One of the reasons I find the Logging Pulse-Oximeters attractive is that I might gradually (over multiple flights) gain confidence in the unit by reviewing that the log captured expected O2 saturation vs. altitude (post-flight review).

These units also log heart rate. An exercise physiologist told me that heartrate commonly increases in parallel with altitude induced reduction in O2 saturation.

Physiology is complicated.