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Bug report: HR spiking when stopping at a red light

My HR seems to spike up when I stop at a red light, which seems illogical to me. It then seems to go back down to where I think it should be when stopping. It seems to happen whether I pause the activity at red lights or not, and also whether I use a chest strap or not.

This is my last run that I did yesterday, you can see the worst example around the 30min mark:

I upgraded from a Forerunner 645 in January and my old watch never showed anything like this. Do you guys think this is a bug or maybe a defect? I'm on the latest beta right now but this has been happening since I got the watch.

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0 nowster over 2 years ago

Do you still have your 645?

What do you do when waiting for the lights to change? Are you jogging on the spot or do you stand still?

0 FoleyRose over 2 years ago in reply to nowster

I gave away my 645 to my sister, I don't have it anymore. I stand still at red lights.

0 nowster over 2 years ago in reply to FoleyRose

One possibility is that the sensor is getting into cadence lock, and it only gets a true reading when you're still. Do you have cadence numbers to compare? If they match the contours of your HR graph, that might be what is happening.

0 FoleyRose over 2 years ago

Here's the graph with cadence. It hangs just below 180 spm for a heart rate around 150 bpm.

0 nowster over 2 years ago in reply to FoleyRose

Nice and even. Not that then!

0 FoleyRose over 2 years ago

My hunch is that it might be related to the auto-pause function. I have that turned off, but it only happens when I do a full stop.

I use a Stryd pod for pace and distance, it could be related to the issue but I don't know why that would impact HR readings.

As a side note, I had a tempo run yesterday and ran with a chest strap and the same problem occurred. My target HR was 163 bpm and a red light spiked it to 173.

0 global_local over 2 years ago in reply to FoleyRose

I would use an external hr-stripe to localize the problem in the same conditions.

0 FoleyRose over 2 years ago in reply to global_local

As mentionned in the main post and my last comment, I do use an external HR monitor sometimes (chest strap) and I can see the same behavior.

0 Marek over 2 years ago in reply to FoleyRose

I'd say that after sudden stop HR should increase a bit because moving legs in fact help pumping blood. But looking at you graps - strange is, that in most cases HR peak appears *after* you start moving again followed by drop. Drops in HR should be whenever you're standing not after that. Looks like graphs are shifted somehow.

0 Steve over 2 years ago

May be related to this issue? So maybe you go there and allow Garmin to look into it.

forums.garmin.com/.../what-is-going-on-with-the-hr-readings-since-14-13