Fenix 8 43mm AMOLED bad wrist heart rate used instead of HRM strap data?

Hi,

I've recently switched to a new Fenix 8 43mm AMOLED watch and continue using my HRM pro strap. When running, I realize that the heart rate shown on the watch and used for alerts (training suggestions) is surprisingly low compared to my former experience on similar tracks with my Fenix 6s pro.

I checked the Fit file: it seems that the watch connects to the HRM and also records the HRM readings from the strap, but shows and calculates with the erratic wrist heart rate.

blue thin line=wrist heart rate

green=heart rate from strap

blue dots=heart rate as shown on the watch and used for training calculation.

Interestingly, when using the cycling activity, the watch uses the accurate readings from the HRM right from the start (I'm not adding a screenshot) and show every second the same value like also the Edge receiving the HRM pro heart rate.

Software is 12.38 on the Fenix 8 and 8.8 on the HRM pro.

What can I do? Quite frustrating to buy a new watch that performs so unusable.

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0 burns3 4 months ago

Try turning off Source Switching

Settings -> Health & Wellness -> Wrist Heart Rate

You have to be wearing the strap to turn it off.

0 Federonic 4 months ago

welcome to the club

Devs are ignoring this issue completely

0 Running_Hans 4 months ago in reply to burns3

thanks, that did the trick!!

In German, the menu position is the same, but it's called "Quellenwahl", so not really intuitive what is meant with it. Switching it to "Aus"=Off helped that the watch relies on the more accurate external heart rate readings.

What I find interesting is that the wrist sensor seems to be so far away for a long time and then finally manages after some 10-15min to get to a better value.

0 burns3 4 months ago in reply to Running_Hans

There’s another thread on this issue and earlier today someone posted a workaround. I haven’t tested it as I’m fine leaving Source Switching off.

forums.garmin.com/.../1898649

0 pgrey 4 months ago

That's weird, I have Source Switching enabled (12.35 and 12.38) and it works fine with my multi-point Wahoo strap. I've done several rides now (mostly when I use a strap, also used by 830 on handlebars) and no issues with it picking up and staying on the strap, until I power the strap down.

0 trux 4 months ago in reply to pgrey

pgrey said:
That's weird, I have Source Switching enabled (12.35 and 12.38) and it works fine with my multi-point Wahoo strap.

That's because the HR Dynamic Source Switching supports only HRM-Fit, HRM-Pro, and HRM-Pro Plus heart rate monitors: What is Heart Rate Dynamic Source Switching? | Garmin Customer Support

0 pgrey 4 months ago in reply to trux

trux said:
That's because the HR Dynamic Source Switching supports only HRM-Fit, HRM-Pro, and HRM-Pro Plus heart rate monitors: What is Heart Rate Dynamic Source Switching? | Garmin Customer Support

Interesting. a h/w spec I wasn't tracking, all of my HRM straps have been either Polar or Suunto, through a lot of years. Thanks for clarifying, BTW.

Reading this though, I don't think I'd want this functionality anyway - who forgets to wet their HRM strap contacts, or who forgets more than once?

These days I'm using a bicep optical anyway, MUCH more convenient and very, very close to as accurate as a chest strap, and no longer competing and don't really need absolute split-second HRM data, a couple of transition beats is close enough for my rides, even the fast-group ones, for me...