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Phoenix 7S - inaccurate heart rate data

smadar_e
3 months ago

The Garmin Phoenix 7S watch shows completely inaccurate heart rate data. Compared to a heart rate strap, there are differences of 20-30 units (the data on the watch shows a low heart rate even when I'm doing intense interval training). The software is updated, the sensor is clean, and there’s no difference between a tight or loose strap on the wrist. Does anyone have any idea what can be done?

  • +1 3 months ago

    I talked to Garmin support yesterday and apparently there is a known issue with HR data with the Fenix 7 series. They believe a fix will be shipped in the next few months. In the meantime, it is suggested to warmup vigorously before the workout begins to lock in HR. A HR strap will also work normally

  • 0 3 months ago

    If you are exercising with a HR strap and comparing it to the HR shown on the Fenix then the latter does seem very low (uslually about half for me). If you put the Fenix into HR Broadcast mode (even though you're not broadcasting it "to" anything) then it seems to more closely align to the HR strap value. Of course, if you're using a HR strap then you don't need the Fenix data anyway.

  • 0 3 months ago in reply to druidh

    I mean, yes, fundamentally HR strap is more accurate for a variety of reasons and if you have one and want more accurate HR information then you should use it. I personally like not having to use a HR strap for my runs because I find them constricting. I've compared the wrist HR to the strap HR and find it close enough for longer z2-z4 workouts that the difference doesn't matter to me. If you're doing strides or HIIT type workouts, then yes HR strap is way better.

    That said, I was simply reporting what was told to me by Garmin support. I was not actually endorsing anything. Garmin is themselves admitting that the Fenix HR data is unusually bad and it is a known software bug. 

    A further note, your broadcasting tip is just wrong. Beyond the fact that there is no mechanical or electrical reason why that would be more accurate, I actually first noticed the incorrect reporting of wrist HR when in broadcast mode. It seems that, alas, there was a bad software update that is affecting the wrist based HR for the moment.

  • 0 3 months ago in reply to wilson2095
    wilson2095 said:
    your broadcasting tip is just wrong

    It's not "wrong" for me. If my chest HRM is showing around 140 when I'm using Tacx, then my Fenix 7 will typically be showing around 70. As soon as I switch it to "Broadcast", the Fenix HR number climbs steadily and with a few seconds it's within a beat or two of the chest HRM. 

    FWIW I'm using version 19.41 software on the Fenix.

  • 0 3 months ago in reply to wilson2095

    I am also experiencing this issue. Hopefully it doesn't take them a couple months to fix it. That's a lot of wonky data to store.