[cbo100]

I've found the watch to be within a percent or two of both store bought and hospital based "finger tip" meters.

You get the occasional outliers from a bad reading but in general that's how I've experienced, and I've had nurses and doctors say that they are "good enough".

And yeah in my experience, anything less than 90-93% in a hospital and they will have you on high flow oxygen pretty quick. So 85% as a single bad reading is fine, but a sustained 85% on a watch means you probably want to head to a medical facility.

[tsimionescu]

Note that, like all constant health monitoring with simplistic sensors, no one actually knows if the Apple Watch is good enough for any medical purpose, or potentially actively harmful.

There simply haven't been enough (or sometimes, any) tests comparing what are normal/safe readings for continuous monitoring in normal life settings of many of these parameters, especially for healthy people, and doubly especially for these types of non-invasive simplistic sensors.

Basically, we don't know how much should a healthy person's pulse/SpO2/... as measured with a smart watch sensor vary during the day. We also don't know which values, if any, should be considered emergencies, or which values should scare you into a programmed visit.

Note that over-monitoring is often just as harmful as under-monitoring in medicine, especially give that the vast majority of the population is healthy (so any false positive is likely to affect many more people than a false negative does, even if in lighter ways).

[kranke155]

Huh? How do we not know all these things if we can just compare it to a finger tip medical oxymeter ?

[tsimionescu]

Because no one is constantly wearing a finger tip medical oxymeter throughout the day and constantly recording their stats - especially not healthy people.