Question: Sportmode: hiking, trail run, mountain climb / mountaineering

trux said:

that it is largely depending on the weight of the watch - the more massive it is, the more intertia and the worse problems locking on the HR,

Agreed.  This is definitely one of the challenges oHRM face.  But this isn't what I'm referring too in this case.  Let's say the two of us are hiking together in the foothills and we're maintaining the same pace throughout.  A 5 mile track, no trekking poles with some rolling hills.  You're healthy and a fit 25 year old male.  I'm a 55 year old out of shape overweight female.  Without question, my HR will be much higher than yours when we finish.  You maxed out at 112 bpm where I was at 142.  If the HR sampling was the same regardless of activity performed, all things being equal, yours will show 112 and mine 142.  But just because we selected the hiking app, Garmin is using different calculations based on activity and yours was still 112, but mine stayed in the 120's.  Had I selected the run app, things may have been correct on my end.  This is the problem and what I was referring too when I said people using other devices aren't experiencing this because their Fitbit, AW5, etc isn't changing the calculations based on activity and those watches are reading HR the same across the board.

No Garmin device will re-calculate the measured HR in any way. It means, if the watch measures 120 bpm, it will show 120 bpm regardless what activity you choose. The only differences in the algorithm for individual activities, are the  intensity of the light, the frequency of the sampling, and possibly some noise filtering, but in no way they are going to multiply the measured HR by some factor, as you seem to be suspecting. That was a wrong interpretation of what ForeKing wrote. 

If the watch measures wrong HR, it either means the system is not well tuned up for your physiognomy, or the fit is not good enough. If you want to be sure, get a HRM belt, and make some comparative tests. It can also help you to find the best fit, or better placement for the Instinct watch. Sometimes it is enough changing the wrist, adjusting the tightness, putting it on the inner side of the wrist, or even on the ankle (though it is then difficult to look at the display   - but for the testing it is worth of trying anyway)

trux said:

It means, if the watch measures 120 bpm, it will show 120 bpm regardless what activity you choose

You've been fortunate that this hasn't happened to you and the hypothetical situation I mentioned is precisely what is happening.  It's well documented in the F6 forum and also commented about in the 945 forum.  And when I say well documented, I'm talking about nearly a hundred.  People are selecting activities and having a HR from the oHRM that won't rise above a certain value.  They've done an identical workout using a different activity profiles and the HR was more online with what it should be.  Garmin's only response is they use different calculations for different activities.  (As you've read in the link provided by ForeKing)  So, I know what Garmin is doing, I just want to know why?  This is what I assumed ForeKing was commenting about.

trux said:

If you want to be sure, get a HRM belt, and make some comparative tests

The technology of the oHRM has improved.  I wear a strap for every workout for more precise data, but I'd like to give the oHRM a shot.  I won't do so because Garmin uses different calculations depending on the activity.  Because no other manufacturer that I'm aware of does this sort of thing, you're constantly hearing how their cheap $30 watch, Fitbit, etc. works but Garmin's doesn't.

I'm aware that the oHRM is affected by complexion, if worn too tight or too loose, tattoos, body hair, sweat, where the watch is worn, temperature, etc.  This has nothing to do with any of that.  I wish the Instinct had the ability to download IQ store apps so you can see what I'm talking about.  There is a data field you can download that will display the HR readings from a strap and the oHRM simultaneously.  If you use the data field while using the strength app, the HR from the oHRM is extremely low and won't go over a certain threshold where the strap is displaying the true HR  Now, you can do the exact same workout only using the cardio app this time and both HR's are inline with each other.  This isn't misperception, as people are posting videos showing the difference.  The strength vs cardio app is just one example.  Garmin's explanation for this is the different calculations for different activities.  The question now is why?  Heart rate is heart rate and the activity choice should have no bearing whatsoever.

tess said:

So, I know what Garmin is doing,

No, you do not know, you just did a premature conclusion. What you know are the effects (wrong HR detected), but you do not know why. When multiple users report wrong HR rates detected by their device, it only means that the HR was not detected correctly, not that the device recalculates the detected HR by some fixed (or variable) coefficient. 

To defintely confirm or refute your assumption, I did a test - a longer activity on a stationry bike in a steady pace, keeping my HR at 100 bpm (+/- 5 bpm). I am used to, and can keep going in such a steady pace easily. Not having any working HRM belt at me, I also periodically rechecked the HR manually (always 25 bpm / ¼min), to make sure I indeed have the pace of 100 bpm all the time.

I then changed the activity type from none, to Walk, Run, Indoor Bike, MTB, Hike, Strength, Cardio, and Yoga, continually pedalling and keeping the steady HR. The watch continued showing 100 bpm all the time (with small deviations of +/- 5 bpm for a few seconds, when I was moving the arm, making slightly different effort, then). 

The conclusion is, that the watch shows exactly the detected HR, with no adjustments, regardless of the activity mode selected, and identical to the HR measured with no activity slected at all.

If you do not believe me, just do the same (or similar) test yourself too. Having a HRM belt, it will be even easier, and I am sure your conclusion will be the same as mine - the activity mode of the watch does not have any direct effect on the HR value.

tess said:

So, you're saying your test disproves what Garmin says.

No, my test disproves only your assumptions, not what Garmin tells. When Garmin tells they use different calculation according to the activity type, it does not mean they simply multiply the detected value by some factor, as you believe. It means, they need to use different algorithms to detect the HR more reliably, and to filter out signal noise caused by the activity (ambient light, changes of pressure, temperature, motion, etc).

Why don't you do the test yourself to see whether you are right or not? If you keep a steady HR (verifying it continuously with your HRM chest belt), then if you are right, each time you change the Activity mode on your watch, the value shown by the watch (and by the connected phone) must change to a different value.

trux said:

t means, they need to use different algorithms to detect the HR more reliably, and to filter out signal noise caused by the activity (ambient light, changes of pressure, temperature, motion, etc).

You're speculating.  Ambient light, pressure changes, temperature, motion, etc. is user specific and not related to HR during an activity.  I can have just as much ambient light reaching my sensor during a run as I can have lifting weights depending on how my watch is worn.  Pressure or temperature?  How do those change how my HR is measured if I'm cycling or doing a HIIT workout?  If it's 75 degrees out and the pressure is 30.10 inHg Garmin measures cycling this way, but a HIIT workout differently?  If it's 90 degrees or 30 degrees, this will affect your HR regardless of the activity.  Do you think anyone will buy into that BS?  You may have touched on something with motion, but this only affects accuracy because of the movement, not the HR sampling rate.  You're telling me I have no idea what Garmin is saying, but you now have knowledge on Garmin's proprietary algorithms that you weren't even aware of earlier today?

trux said:

Why don't you do the test yourself to see whether you are right or not?

How many times do I have to say that I've (and many, many others who have also posted videos) already conducted test before you stop asking me to do so?

I really don't have the time, nor the patience to continue on with this discussion with you.  Let's omit all opinions and speculation and stick with undisputable facts.

Fact 1.  Garmin states:

Additionally, HR is calculated differently for each activity.  Use the activity app that matches the activity being done.  For example, using the Elliptical app while running outdoors could result in incorrect HR being recorded.

https://support.garmin.com/en-US/?faq=xQwjQjzUew4BF1GYcusE59&productID=621922&searchQuery=optical%20heart%20rate&tab=topics

Fact 2.  Seven hrs ago this information was news to you.

trux said:

Yes, you are right. Makes sense. Thanks for the link.

We'll let other users follow our discussion and come to their own conclusions.  There's no need to continue every reply with more nonsense using the pretense you know what you're talking about.

Ambient light, pressure changes and temperature will affect all activities with the WHR equally.  I've seen the same problems with my Fenix 6 and have done the test with the auxiliary hr app you spoke about.  Trux doesn't know what he's talking about.  

who knows said:

Ambient light, pressure changes and temperature will affect all activities with the WHR equally.

You misunderstood, what I meant. The intensity of the ambient light penetrating under the watch depends on the strenght and on the period of the arm motion. The pattern and the strenght of the motion differ at diverse types of activities, and hence the need to filter out this parasitic signal differs, too.

The same goes for the pressure. I spoke neither about the atmospheric pressure, nor about the arterial pressure, but about the variations of pressure the watch transfers on the wrist and the veins, creating hence waves in the blood stream, and again parasitic signals.

And the temperature plays a great role at OHRM too. At low temperatures (winter sports, water sports), it causes strong periferal vasoconstriction, which has essential influence on the HR detection.

who knows said:

I've seen the same problems with my Fenix 6 and have done the test with the auxiliary hr app you spoke about.

So you changed the activity type during a steady effort with constant HR shown by the HRM belt, and each change of activity type on the watch triggered a change of the HR on the display? Could you share the data? My HR was at 100 bpm during 30 minutes, while I was changing many activity types on my watch, and the value on the watch remained on the same level, regardless of the activity type chosen. No difference observed at all.

If you did the test, you certainly discovered which activity types modify the displayed HR. Let me know which ones modified the HR values and how. If I did not try them, I'll do the test happily again.

trux said:

The same goes for the pressure. I spoke neither about the atmospheric pressure, nor about the arterial pressure, but about the variations of pressure the watch transfers on the wrist and the veins, creating hence waves in the blood stream, and again parasitic signals.

And the temperature plays a great role at OHRM too. At low temperatures (winter sports, water sports), it causes strong periferal vasoconstriction, which has essential influence on the HR detection.

Yes, but how do these differ between walking, hiking and running in those same conditions?  My heart rate will react the same no matter what I'm doing.

trux said:

So you changed the activity type during a steady effort with constant HR shown by the HRM belt, and each change of activity type on the watch triggered a change of the HR on the display? Could you share the data?

Kind of.  Starting certain activities will show a great difference between the WHR and my HRM-Tri after steady effort.  Speed walking never goes over 100 even though a manual check shows I'm pushing it to 115-120.  Stopping the activity and starting a run show equal heart rates.  I will have to do them over again and then post  because I don't where they are saved.  Do you have another garmin watch you can use to test both WHR and your chest strap at the same time?  You can also go to the Fenix 6 forum and watch several videos showing this behavior.