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Wrist heart rate monitor WHR inaccurate

jkoplik
over 5 years ago

I am seeing same issue.  I'm posting a picture showing a Garmin 935 on one wrist, and a Garmin 945 on another wrist (excuse the makeshift armband, I can assure you the "tightness" is same on both). So, this is same person, skintone and setting...just a different 1 generation older Garmin model watch using OHR.  They are showing wildly different readings:  54 BPS (on 935, top) vs 147 BPS (on 945, bottom).  

Because the 945 OHR appears inaccurate it is compounding issues with the 945 that have changed and were supposed to be FEATUREs and a reason to buy it in the first place (I may not have all the Garmin marketing terminology correct here):

New Feature 1 - Exercise Load:  The new watch (and perhaps Garmin in general) seems to have shifted to using "Exercise Load" -- versus the old way of using Training Stress Score (TSS).  Since Exercise Load is based on EPOC and therefore, an extrapolation of Heart Rate using software modelling, none of that load for a given workout is accurate.   IMHO:  If you are going to switch to this EPOC methodology, you have to be very very sure the HR is accurate or be able to have a user setting to go back to TSS.

New Feature 2 - Fitness Training Progression:  Using EPOC from New Feature #1 cannot be showing fitness recovery vs fitness progression over time because EPOC is not accurate to begin with.  For example: The watch keeps claiming I'm doing "High Aerobic" workouts when in fact, I know I'm doing only a "Low Aerobic" workout (like a Recovery Spin).   I've been fighting with this watch for weeks trying to understand how I could not be in recovery by this point!!  Looks like I will ignore and use Training Peaks TSS ....

New Feature 3 - Abnormal Heart Rate Alarms:  I had an "Abnormal Heart Rate" alarm go off yesterday just watching a football game (well over 100, just sitting there, nothing exciting going on).  I was so alarmed I almost made a Heart Doctors appointment today until I found this thread!  

Old Feature - Heart Rate Zones (useless):  I recently completed a Triathlon and used the watch for Run Pacing and wanted to stay in Zone 2 as it was long course.  However, it kept telling me I was at or above Threshold (Zone 3->Zone 4).   I couldn't figure out why it was running so "High" as I did not feel I was exerting myself -- and forced myself to Walk many of the segments to stay in Zone 2 and be able to finish the race.  Therefore, it impacted my race time!!!!   Admittedly about 3/4 through the race I started to "just race by feel" and ignored the watch... but the watch is supposed to guide here.  Further,  psychologically, I was really getting down in the race thinking "What Am I doing wrong"  ... "Am I drinking enough and getting dehydrated and that is why heart rate is so high", "is it heat related", etc.....

Don't get me wrong:  I've been an avid fan of Garmin triathlon watches for many many years and have also owned since the Garmin Forerunner 910XT and always upgrade - I've never had any issues like this.  However, at this point, I'm thinking of going back to the 935 which I'm glad I had not time to sell yet.

Can anyone from Garmin help here?  The watch is clearly defective and should be fixed immediately either through software update or replacing these altogether.

  • 0 over 5 years ago

    Regarding the WHR, if this is a persistent problem I'd try first with a proper hard reset (not hard restart). If this won't help, you'll have to exchange your watch.

    Regarding the firstbeat features: I strongly recommend using a chest strap. Everything else just isn't accurate enough for the calculations needed in said features.

  • 0 over 5 years ago

    What happens if you switch watches between wrists? What software version are you on? Have you tried a hard reset of the watch?

  • 0 over 5 years ago

    I should also mention that this has not been my experience at all. I had a 935 and a Fenix 5+ before getting the 945 and I seem to have more accurate WHR readings from the 945 by far.

  • 0 over 5 years ago

    If you believe the watch to be defective then you need to contact Garmi Support through the support channels.

  • 0 over 5 years ago

    You may want to try switching wrists. It is possible that the blood supply on one wrist is deeper than the other.

    Also, the photo of the 945 appears to be close to the wrist bone, which can generate problems with OHR accuracy. Wearing it on the fleshy part of the wrist away from the wrist bone generates less "bounce"and ensures a better seal against external light entering the sensor. This may just be camera angle, but that's the way it looks.

    The 935 used EPOC rather than TSS as well. No change here. It is just the 945 and Edge 530/830 are more explicit about it.

  • 0 over 5 years ago in reply to mcalista

    for my point of view TSS never used for Training Load, it was always EPOC in the past, if you have a powermeter you only see TSS for cycling but never for running with Garmin Power or STRYD

  • 0 over 5 years ago

    I think I have roughly the same experience. When outside of the activity mode and using all-day tracking I feel the OHR displayed is WAY too low (around 50 bpm too low). Especially when you become active from a resting state, for example when you sit, then walk to your bike and then start cycling. My rest heart rate is around 50, walking to the bike it rises to around 85-90 and when cycling it stays at around 90 or drops to around 80. I noticed that when I then start an activity on my watch it picks up the correct heart rate in seconds (around 130-140) and it is as accurate as wrist based OHR can be. I can then stop and delete the activity and let the all-day tracking continue and it stays accurate for the remainder of the bike ride. That happens every single time when cycling and sometimes I must use this method for walks too. As the watch and Garmin ecosystems rely on OHR data I feel this is a watch-breaking bug that needs fixing.

    And yes, I have tried to reset my watch and even completely reïnstalled after a factory reset.

  • 0 over 5 years ago

    If I really want my HR and my firstbeat metrics to be correct, than I have to use a chest strap!

    I also try to understand the wrist OHR of the Forerunner 945. Up to now I’m using the “Auxiliary Heart Rate” data field to compare the OHR to a chest strap.

    OHR is very bad in activities like outdoor cycling. Than you have done a triathlon it can be that the OHR was not able to get a correct value after your cycling part.

  • 0 over 5 years ago

    I've found OHR/WHR inaccurate mostly when watch is too loose on my wrist or my wrist veins are too deep - usualy when I am cold (or my arm is cold)

    For daily activities I've setup an alarm for abnormal HR, once it happens I remove the watch or allow it to find veins on the other side of the wrist.

    For cold days I am trying to keep the watch and wrist warm - I am putting it under a sleeve or a glove. 

    For high effort activities HR measured seems always fine, as the blood flow is bigger that usual.

    For activities I care about HR more then usual I simply carry HR strap.

  • Former Member
    0 Former Member over 5 years ago in reply to JeremyBlck
    JeremyBlck said:
    I think I have roughly the same experience. When outside of the activity mode and using all-day tracking I feel the OHR displayed is WAY too low

    forums.garmin.com/.../1024467

    forums.garmin.com/.../hr-is-inaccurate-during-daily-tracking