Poor pulse oximetry accuracy.

My wife has a vivosmart 4 and I recently got myself a fenix 6 (now software version 8.10) titanium sapphire and I've been comparing the pulse oximetry of the two devices on both of my wrists followed by my wife's wrists with a professional pulse oximeter and the vivosmart 4 is surprisingly often within 1% accuracy of the professional device. The fenix 6 on the other hand is usually underreading by >= 5% all the time. I'm aware this is not meant to be a medical grade device but the numbers it gives are so much less accurate than the much cheaper device my wife has, and the values are so low that they'd warrant hospital admission or professional sleep studies when they're not warranted. I would not normally pay much attention to the values it gives since they're meant to just be there for trends rather than accuracy, but the much cheaper device being far more accurate is a little disconcerting when they apparently use similar sensors. It hasn't improved in a week of usage. I've tried tightening and loosening the band and on both wrists but the issue persists. I've seen other people posting their oxygen saturations and they're often in the low 90s when healthy young people at normal atmospheric conditions should always be in the high 90s. Do you have any suggestions, or is there any effort being put to improve it? Thanks.

  • I am in the middle of the 60’s , use to meassure two,three times a day, usually from 94 up to 96, sometimes 97. Happy with that, got the same device as you, running currently 8.74 b.

  • 97 is about what most people should be, whereas mine usually reads 91/92. Did you notice a change going from 8.1 to the 8.74 beta?

  •  No, i think it’s been more or less the same with most of the software. I used it a period during sleep, but stopped because of the battery drain, but i think its been more or less stable.Tried again now, as you can see 97%.

  • Thanks. I'll give it more time and it'll calibrate(?) somehow and improve. It does seem to be gently trending upwards over the last few days though that's not how an oximeter should work, but I don't know about these.

  • My Fenix 6 usually shows pulsox in de mid to high 90s during the day and around an average of 93-96 during the night. I guess this should be fine. But it usually drops 1-3 times a night to values in the mid 80s and last night once even to 79 (which is a outlier, i haven't found another time where it dropped to a concerning level). I think my sleep is fine so i don't know if this should be concerning or not.

  • I have F6, F6X, Delta, and VA4.  Have so far tested F6X and Delta against my Innovo iP900AP Pulse Oximeter.  With maybe 5 randomly timed tests the watches have generally shown EXACT same % 3 times and +/- 1% the other 2 times.  Have not yet tested the VA4 since I've not been wearing it, nor the F6, which I wear for activities and not to sleep or daily.  I'm satisfied.  I would contact Garmin for replacement if the problem persists.  Disclaimer of course is who is to say WHICH device is right, "professional" or otherwise.  

    I'm more interested in order of magnitude and if MOST of my devices start showing a similar difference I'll treat my condition accordingly. 

  • I have exact same night time readings performance.  I am a heavy cigar smoker (don't inhale) and about 30 lbs overweight. Also approaching 60 years old.  I think it's affected by movement and definitely when you pin the arm under you.  I have found gaps and can correlate those to when my left arm fell asleep, so less blood flow.  Another thing I've found--like last night--when I occasionally take Benadryl to sleep I move less and readings are complete and above 90%.  Makes me feel better.

  • i was going to mention that it's my understanding that the current lineup of devices all use the exact same sensors, so any variance necessarily due to either specific usage issues or firmware

  • I watched it in the span of one minute go from 89 > 92 > 97.  I freaked, a little bit, and ran three tests.

    I used to get the night drops, where it would drop in the 80's at a single point during the night.  Don't know if it was a real problem but it stopped doing it after a firmware upgrade, so probably a Garmin problem.  Now it's 93/94 at night and 96ish during the day.

    When I've been able to successfully test against a finger reader, it so often fails to read, it's typically 2-3% under.

    A lot of things in this watch, so I get that they won't all be top end performers, but pulseOx is pretty hit and miss for a $1,000 device.  I know this isn't a medical device, and pulseOx is meant for acclimation, but things need to work better than they do in Garmin land.

  • How consistent are the readings?  For me, I'm more concerned about trends and sudden variation from where it is on average.