PulsOx accuracy?

Anyone compared Garmin's PulsOx with a medical grade oximeter?

I suspect Garmin is not very good. For example, right now, my Fenix just measured 91%. When I used Samsung's app on my S9, I got 98% (measured on a finger).

On Fenix, I'm getting an average daily readings of around 93-95% but during night I see it dipping to 90 or even 85% (average about 92-93%). Seems low as I don't have any medical condition.

Could it be that for wrist measurements, it's more sensitive to position of the watch? Or blood flow through the wrist?

I don't understand, why there should be such a difference between Fenix and the phone app?

  • I just bought a finger pulse oximeter last week and I have been testing it against my Garmin and, honestly, I mostly get the same reading or within 1-2% every time.  And it has some extra features like a pleth graph showing heartbeat and a perfusion index reading showing how accurate the reading is.  Not all have this and I recommend these features as it shows you the accuracy.  I also have compared my heart rate on the pulse oximeter to my heart rate on the Garmin and those also are almost exact. I have been impressed that my Garmin is keeping up with this higher end pulse oximeter.

    The thing you have to remember is that some pulse oximeters require you to remain perfectly still and some do not.  The pulse ox sensor on the Garmin requires you to remain perfectly still, your entire body.  The reason people are getting readings all over the place with all day monitoring is because you are not perfectly still every time it attempts to take a reading.  And even at night, you are moving and/or sleeping on your arm and not getting accurate readings.

  • Which model do you have?  I'm always curious if people with the less heavy smaller versions of the Fenix have better luck.

  • I have the 6S Sapphire.  I do wear my watch fairly tight also.

  • I have the 6S Sapphire

    That's a lighter watch and I really like it.  If only it had a bigger display for my old eyes.   I do think the lighter watches tend to perform better as they don't wiggle so much.

  • Sure Slight smile By the way don't forget that Fēnix doesn't  measure oxygen saturation constantly  unlike a cardio monitor ;)

  • That could be.  I do like the smaller size on my tiny wrist, but I have old eyes too so I understand wanting the bigger face. I had to buy prescription Oakleys a few years ago to run in or I couldn't see both the trail in front of me and my watch.  One of my better running purchases for sure.

  • I think it's bonked, maybe even worse in the recent updates.  I just scored a 88%, rolled over to the Apple Watch and 97%.  I did an all-day yesterday and got some really low numbers, so, once again, Garmin drops the ball and breaks as much as they fix on an update.

  • This has been the problem since Garmin laid off their main development team and now outsources it.   It's a real mess.  I also believe that they try to put too many features on the watch instead of fine tuning the core purpose of the watch.  I mean, how many of these features do people really use? 

    Even on my Apple watch 6, I use maybe 5 or 6 things on a daily basis.  The main thing being imessage.  Having a cellular watch is very liberating, i don't carry a phone anymore.

    Would love to see a Fenix Pro sized display on a S, and with cellular.  Would also like to see them go back to the core functions of the watch and get them right.