Fenix 8 heart rate jump

In every running activity, first about 5 minutes is the heart rate very low (even i run very fast and can feel my heart rate is high) and then it jumps up by about 20 beats and start working correctly . It appears every run and it doesn’t matter if I use optical sensor of my watches or hrm-pro belt. Please fix this problem I never experienced something like this, but it started when I bought new Fenix 8 watches.

Top Replies

S.M.R. 6 months ago in reply to Johnny.P +2 verified

Do you not have the option on Fenix 8 , under the HR widget settings to disable Source Switching.

This was something added to the FR series I think in the 19.XX beta process to enable one to disable i…
Vivialux 6 months ago +1

Same problem here.

Also present on Fenix/Epix 7 Pro from some months.
Johnny.P 6 months ago in reply to S.M.R. +1

FAB! I found it and disabled it, will see if this will help at my next run thank you

All Replies

0 Johnny.P 6 months ago

0 Vivialux 6 months ago

Same problem here.

Also present on Fenix/Epix 7 Pro from some months.

0 iNeO 6 months ago

me same. happened with epix 2 too.

0 simacekjakub 6 months ago

If you run with HRM-Pro, export FIT file, open it in fitfileviewer.com, open chart, put "wrist heart rate" on axis y1 andd "external heart rate" on axis y2. Can you see any differences? Is that jump present on both graphs?

Even if you run with HRM-Pro, that does not necessarily mean that Connect shows you HRM-Pro heart rate. There can be some automatic where watches decide which source of HR is better at some points.

0 Johnny.P 6 months ago in reply to simacekjakub

And is it possible to turn this anutomatic off? I want the data just from hrm-pro. But I will try to follow your guidance. And let you know.

but the main point is, this should be fixed and it looks like sw problem . It cannot be like this, every run it jumps by about 20 beats after 5 minutes…

+1 S.M.R. 6 months ago in reply to Johnny.P

Do you not have the option on Fenix 8 , under the HR widget settings to disable Source Switching.

This was something added to the FR series I think in the 19.XX beta process to enable one to disable it using both HRM and OHR (after they made that system in earlier FW updates)

I have source switching disabled so when I have the HRM connected it ignores the OHR.

forums.garmin.com/.../hr-dynamic-source-switching

forums.garmin.com/.../question-regarding-17-23-and-dynamic-heart-rate-source-switching

You have to have the HRM connected to adjust the setting , if I recall correctly.

0 Johnny.P 6 months ago in reply to S.M.R.

FAB! I found it and disabled it, will see if this will help at my next run thank you

0 simacekjakub 6 months ago in reply to Johnny.P

Would be still good to look at the graph I suggested in the post before. I am actually curious about it, because I check this periodically with my activities and my experience is that my F8 is amazingly accurate. HR graphs from OHR and HRM are always nearly the same, talking about running and inline skating mostly.

0 Johnny.P 6 months ago in reply to S.M.R.

Works fine. Now, all data are collected just from the HRM and no jumps etc appears. It works exactly like on my previous watches. Thanks a million for help,it really helped me a lot.

0 Tparaskevas 5 months ago

Same problem here after a while 5’, 15’ or 25’ minutes, it jumps to a higher position.