Wrong HR even during low intensity activities

The high value that you get sometimes, is probably your walking cadence. Same thing happens now and then during running, with values around 180. I guess the sensor picks up both frequencies (cadence and HR), and selects the one that is currently strongest.

Thanks for answering ovekvam but either I don't understand your theory or it's wrong.

ovekvam said:

I guess the sensor picks up both frequencies (cadence and HR), and selects the one that is currently strongest.

I'm not familiar with ANT+ protocol, but I'm sure there would be some safeguards from picking the wrong signal and using it of HR instead of cadence.

Indeed, I had footpod attached to my shoes yesterday, but it wasn't ANT+ but a Bluetooth one from Adidas(I've bought two from old stocks one ANT+ another Bluetooth for my wife so she can use it with her phone via Wahoo).

On the top of that my chest heart rate was disabled in sensor settings only footpod and Tempe was enabled and when I run with a chest strap I have never seen such quirks at all, everything works flawlessly.

Also, I've got footpods relatively recently and previously I was testing without them, so there should be no interference from them, but I surely repeat the test without wearing one and removing them from sensors if that's necessary.

And, just to prove that there is no correlation between cadence and heart rate, please check another two graphs from the same walk, I added cadence field now. As you can see cadence was pretty constant aside of few stops but heart rate was living it's own life not correlating with cadence in the way you've pointed. If you examine blue line by Vivoactive we'll see that it reaching 125 a few times but there is no distinct increase in cadence.

You understand my theory wrong. When you move, you have a cadence that physically shakes your heart rate sensor. That will generate a reading from the sensor with a frequency similar to your cadence. I don't mean that another sensor is disturbing anything. The heart rate signals read by the sensor (not the ones sent out from the heart rate algorithm) are quite weak, and are easily disturbed. For the heart rate to work, it needs to overpower noise like the cadence.

Since Garmin knows our cadence at the time, they could (maybe they are) use that frequency to dampen the cadence frequency in their heart rate algorithm. It would work a bit like head phones with noise cancelling, subtracting the noise.

ovekvam said:

You understand my theory wrong

ah thanks for clarifying that, and indeed I get it wrong, it sounds plausible but  if you look at my graph from 700-1000 there is clearly no change in cadence but the pulse is going quite high at the same time, and I believe that it wasn't happening prior upgrade to first beta of 6.03(or something) the one which has issues with crashing and enabling PulseOX every morning.

Anyway, I'll see if I can find those activities to post more proofs and possibly record another one with Vivosmart HR just to show how better it is in measuring heart rate comparing to the newer device with more advanced sensors. Also, I'm thinking about recording some activity when my arm with the watch isn't moving, just to test your theory a bit. 

I never get cadence disturbances when cycling, but sometimes when running or jogging. Mostly with wrist based heart rate, but also sometimes with chest belt. I also had a Vivoactive HR which didn't have this issue so much, but it was also a lot less responsive.

ovekvam said:

I never get cadence disturbances when cycling, but sometimes when running or jogging.

That's very interesting observation, I may look if I measured HR separately during cycling. And yes if it happens only during jogging and running but not cycling then I'm ready to adopt your theory too as the main version of the issue. In any case if the problem really wasn't apparent before then I'm pretty sure that Garmin can do something about it in newer firmware releases.

Optical HR cant be precious on the arm. Even an finger-Ox fails while moving the arm.

Optical is fine while sleeping, resting or average daytime duties.

If you do serious activities use an Cheststrap. Cadence disturbing comes from bloodpressure changes while moving the arm. Optical HR cant see the difference between the heartbeat or bloodpressure changes from movement.

MB201 said:

Optical HR cant be precious on the arm. Even an finger-Ox fails while moving the arm.

Optical is fine while sleeping, resting or average daytime duties.

sure, I totally aware of this and you're right. That's the main purpose of my watch's optical sensor is to watch the trends of resting and average daily heart rate.

MB201 said:

If you do serious activities use an Cheststrap. Cadence disturbing comes from bloodpressure changes while moving the arm. Optical HR cant see the difference between the heartbeat or bloodpressure changes from movement.

That was the main idea why I got a chest strap way before I got my watch. Your arguments are totally valid, but still why we can't we have a better performing device especially if other company's devices somehow manage to bring better results even during runs, as we know Fenix 6 share same hardware as Vivoactive 4. Also, as I've pointed a few times earlier prior to version 6.x my comparisons didn't show such discrepancy in results, and way older device namely Vivosmart HR was better in tracking HR data somehow. So I think that asking the developers to improve this is totally legit, it's not a new feature but a base one, and my post was done in hope to see if other people have that issue or not.

BTW here is another post from Venu's user who spot the similar behavior:

Hi.

Did I get it right? That HR not accurate on Garmin while moving...

Mine showing 20 or 30 digits more than my actual bits, even when just walking, only pretty accurate when not moving sitting still and resting 

When I'm  running it always alerts me about high HR, because I did set alarm, but it far from actual HR...

Is there any chance to calibrate it ? Because otherwise this option useless... 

5119500 said:

Did I get it right? That HR not accurate on Garmin while moving...

That's correct but i wanted for it to be  confirmed by more people before asking Garmin to do something about it. That's why I did those measurements.

5119500 said:

Is there any chance to calibrate it ? Because otherwise this option useless... 

Unfortunately we can't do much about it, as it seems. The best way not to have the issue is to invest into some chest strap, there are plenty of offers starting from $20 and up.