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?

  • At night time your blood OX often will drop to low 90s\ high 80s at times this is normal as far as I know (depending on the frequency and exactly how low it may also show sleep apnea). 

    During the day I would say that the accuracy may be questionable... When I first purchased the watch it was always showing between 96-99 and for the last few months it's been showing on average 91 - Now it's back to 95-97 daily. It could be that my blood oxygen was lower during those times but as low as 90% is questionable...  A member of my family is a nurse and that said that is not possible without showing signs your oxygen is that low. 

    The only thing that you can change to affect accuracy of the watch would be to wear it snuggly and maybe in a darker location as external light might interfere with the sensor. You could also try swapping wrists or even holding to a different part of the body (which may be difficult as I know it's very sensitive to movement so you'd have to hold it still). 

    Unfortunately I do not have anything more accurate to compare it to or any device for that matter...  In your case I would likely trust the 98% reading more. They also do state it is not a medical device this is likely because they know it is just an approximate figure and not super accurate.

    Not sure if this helps at all just my experience! 

  • I have actually.  Thanks to a visit from the table saw fairy, I've been in surgery and post op a few times this year.  My particular fenix 6X consistently measures 3% lower than the hospitals oximeter on each visit.

  • Mine used to be in the 96-99% range for the last 10 months but in the last month or so, it now reads in the 91-95. It could be something in the last update screwed something up. Yesterday, my fenix showed 92 and a separate pulse oximeter showed 97%.

  • I had bad experience with PulseOX accuracy with many Garmin watches since it first got introduced, so I turned the feature off when receiving my 6 Pro Solar 2-3 months ago. It just consumed battery with no accurate information. 

    I turned it on again 12h ago to see what or if it has improved over the months. And comparing it to the AW6 I will sent back tomorrow.

    I am on FW 11.76 Beta with all the updated sensors within that FW. So far it has been QUITE accurate. During sleep till now it has never been lower than 95%, an average 96% during my sleep this night. Of course I am sure I have 97-99% most of the time. Still, way better results than I got a few months ago. Back then it was all over the place, often, almost always 85-93%, not very often above 95%, while the Pulsoximeter on my Finger read 97-99% all the time. I tested it with Vivosmart 4, FR245m, Fenix 6S, all the same, bad, results. I don't know what they have done to the sensor SW or if they have updated the sensor itself with the Pro Solar version somehow, but I am happy atm. Almost the results from Apple Watch 6 and around 2-3% lower than a good 60$ Pulsoximeter. That would be ok for me and a reason to turn it on full day. If it stays like that. Only been 12h so far...

    Maybe with AW6 introduced Garmin thought to improve the sensor as Apple has come out with a PulseOX sensor watch too? Whatever, way better till now then back then. 

  • I'm still running 11.10 and I'm seeing like 91%-94% during my sleep, which is just bullcrap.
    I have no problems with sleep apnea or breathing. Usually around 98%-99% when measuring with a real medical device.
    Hopefully it will improve when 11.76 is released ...don't have time for beta testing now Slight smile

  • seems pretty accurate to me, but then again i'm no strapped to a medical grade machine 24/7 to benchmark it

  • From my testing the accuracy isn't awesome compared to a finger monitor. But, it has been consistently wrong.

    In many cases, I think the PulseOx trend line is more important than the raw number, so while I'd like it to be more accurate, it does provide a useful metric.

  • For me it's been just a random number generator between 90 and 100%. In these Covid times it's extremely depressing to see some 91% values, yet on the second try it reads 100% without changing a thing. Third try - 94%, then 98%. So basically completely and dangerously useless.

  • Pulse ox on both of the 6X Pros I have had has been completely unusable.  It doesn't matter where or how I wear the watch I consistently get low readings.  Even sitting still in a chair holding my watch at chest level following the manual to the letter does not provides usable results.  Both accuracy and precision of measurements are total garbage.  For me it's an absolutely broken feature.

  • Hi.

    My experience was that with a professional pulse oximeter on my finger and the watch on my hand was a difference by 5-6 even 10 percents.

    Garmin always show lower values.


    - pulse oximeter - 98%

    - Garmin - 91 %

    another try

    - pulse oximeter - 97%

    - Garmin - 89 %

    another try

    - pulse oximeter - 97%

    - Garmin - 92 %


    So the pulse OX function is more an advertising thing.

    The watch/band measurements are easily influenced by the ambient light, the tightness of the strap, position of the hand etc. So is not reliable at all.

    Unfortunate the pulse OX feature consume half of the battery life in vain.