Fenix 6 Pro: Increased Heart Rate Inaccuracy (too high for running activities) Since Beta 11.75 and Now 12.20 Release


It seems my Fenix 6 Pro optical heart rate sensor is reading with even greater inaccuracy than prior to the beta 11.75 and now official, 12.20 release. One could argue my perceived exertion is simply less but when I take the time to manually check my heart rate during a run or immediately after, I find the Fenix 6 to be around 20-25 BPM higher.

It also seems to be reading higher while cycling but not by as much. I have always found the Fenix line and the optical HR to be a bit more stable and reliable while cycling. 

My resting heart rate, with a little distance between the measurement and an activity tends to be quite accurate still though.

Is anyone else experiencing a significant increase in the recorded optical heart rate during runs (both trail and road) (if not other activities)? 

Thank you!

  • I have the same problem... Almost + 35 BPM (on average) for any pace... 

  • exactly the same issue for me. in fact i came in thinking of starting a thread on this. Went for my first run with 12.2 and my HR was about 20 higher then it should. it than settled down to reflect a more accurate reading but a couple of minutes later jumped up another 20 or so again. This is very unfortunate since WHR had worked just fine on 11.1. Please resolve asap

  • Yes, I have a similar problem, but if 11.76 my heart rate is too high, then at 12.20 I run at a speed of 10 km / h and a heart rate of 70 beats per minute. connect.garmin.com/.../5715178909

  • Yes, I have a similar problem, but if 11.76 my heart rate is too high, then at 12.20 I run at a speed of 10 km / h and a heart rate of 70 beats per minute.

  • Bonjour j ai fais le même constat avec entre 5 à 10 pulsation supérieur de ma fréquence cardiaque de repos. Et ce dès l instalation de la 12.10. Coincidence? Je ne pense pas 

  • At least there is some solace in knowing I am not alone.

    Amoins, il y a du réconfort à savoir que je ne suis pas seul.

  • Yes, the same problem. It is necessary to run with a chest strap, otherwise the heart rate values are higher.

  • Glad to hear that I'm not the only one having problems since the 12.20 release.   I have exactly the same HR increase issue, but in addition I also have the following issues:

    • VO2Max does not show up in the overview for the runs since after the upgrade (Garmin Connect)
    • Training status is not correctly updated (does not take the latest runs into account)
    • Training performance is not shown during the run on the watch, and does not show up anymore in Garmin Connect (for the runs since the upgrade)

    Anyone else experiencing this as well?

  • My OHR seems to have jumped up by 20-30 BPM since 12.2. If i power walk with my wife I get a higher BPM than I got on my runs. Not tried a run since 12.2 but will up date when I do. I will also try the WHR/Strap delta data field next time to see if the difference has changed significantly.

    Update: I tried a reinstall with webupdate. Went on my power walk and added a chest strap with the HR Delta data field, initially the OHR was a bit higher then it settled down to a + 1 - 7 bpm difference. At the half way point, 3 miles the started to climb until the OHR was between 50% - 100% higher until the finish. Will try another software reinstall and try again.

    Update 3 Nov: Well I carried out another webupdate reinstall and a few reboots before doing my 6 mile route. This time I again wore the watch plus my HR chest Strap and used the Delta widget to show any difference. As a test measure I also wore my old Garmin FR60 with a Scosche Rthym+ OHR armband. This has always been reasonably accurate. All three HRM's were good at the start, within a few beats of each other. At about 1.5 miles the wrist OHR started to climb and began to show a delta anywhere upto +50-60 BPM. Slight improvement from yesterday but too much to be usable. The scosche Rythm+ OHR stayed close to the chest strap throughout. The Strap HRM below is pretty normal for this route going back years, any peaks and troughs are terrain based. It is a power walk so not expecting large variations in HRM. I think in the short term I will use the Scosche for walking and running and the chest strap for bike and leave the watch sensor for daily use. Hopefully there might be future improvements. I may even downgrade the software.  


  • I paid 850€ for fenix 6x sapphire plus 100€ for HRM RUN and I cannot have music and hr data while running!