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

Hi Chris, I don't think a type of activity will really change the sensitivity of the watch, as you can set "recording interval" from the system settings and then GPS mode per activity. You can also modify activity on Connect after the event, and change the type. I tend to use Hike for mountaineering too, as I configured the data screens the way they are more useful for me in both cases, but I can see the need to have run and trail run as separate activities (for things like 3D speed and distance for example). However, I use Run for all kind of running activities, on the road or on the trail.

I know this is old but just to give a better answer since I looked for this on google. Different activities calculate heart rate different. For example if watch thinks you are not doing an activity the heart rate monitor has a "soft cap" on what HR it reads. This has been my experience. I can climb some stairs (10 flights) and get my heart pumping while wearing watch correctly with no activity set and HR wont' go over 80-90 bpm when in reality I'm closer to 160 bpm through manual check. My resting hr is 47 and ranges up to 60 bpm which is accurate and always detected correctly by watch.

When doing anything active you need to use the proper activity to get the most accurate HR reading. Hike vs climb i'm assuming has similar "soft" caps. I went on a 4.5 hr hike yesterday (forerunner 945) and climbed 1700 feet using hike activity and heart rate rarely read over 125 even after strenuous parts. Hikes are meant to be casual strolls through the woods (think rolling hils) and climbing are going up and down elevation in the woods where you will sometimes use hands to go up and down or have your hands on your knees to go up long stretches. Your hr will be much higher during this. Furthermore in certain activities the watch takes into consideration the use of your hands when calculating HR. Most "hikes" should actually be classified as climb as far as the watch is concerned if you are going up to a view point or lookout point. Trail run is probably similar to climb in that it is open to interpreting very high heart rates if need be. 

Hope this helps. Garmin has directly stated different HR calculation algos depending on activity. As far as data screens every single activity can be set to look like any other activity so that isn't the reason for "hike" or "climb" or whatever. 

ForeKing said:

Garmin has directly stated different HR calculation algos depending on activity.

Could you post the reference to this statement? I never saw such claim, and my Instinct records the HR pretty accurately, regardless what activity type I select, or even when I do not select any activity at all. Tthe HR value also does not change when I start an activity.

I'd rather tell, that in some cases, the watch simply locks on your pace, or on the arm movement, especially if the fit is not sufficient, or oppositely when it is too tight - in such case the variability of the ambient light entering under the watch, and/or the variability of the pressure of the watch on the veins, may cause the false reading.

Otherwise, to the original question - there are different parameters that differ at individual actitiy types. First of all it is the type of screens and the info you get on the watch, and then also the monitoring values and graphs, stats, and categorization differes in the Garmin Connect account. 

Certainly. Please see the following link:

https://support.garmin.com/en-US/?faq=xQwjQjzUew4BF1GYcusE59

Go to the section heading that says "Certain types of Activities Can Affect Heart Rate Performance"

If I had to extrapolate further Garmin mentions the HR monitor has to "use more power" to determine HR in darker skin types. I am willing to bet certain activities require more power from the HR monitor compared with resting. When doing no activity lets say power consumption is 1 and it probably takes less readings or processes them less vigorously because there is no need for more juice. Then walking activity maybe it gets bumped up to 3, then while hiking maybe it is 5 while running it gets bumped up to 8/9 and if it is struggling because of skin color or other reasons maybe it kicks in extra gear and goes to 10. These changes are probably extremely minute but it shows why it is important to select an activity when doing anything above and beyond resting/sitting or easy walking. But this is just my guess. We know for a fact that activities involving hands or being outdoors use different calculations than ones that don't and from my personal experience more "intense" activities have more accurate readings at elevated heart rates than less intense ones overall probably due to more power demands from OHR unit.

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

ForeKing said:

When doing no activity lets say power consumption is 1 and it probably takes less readings or processes them less vigorously because there is no need for more juice. Then walking activity maybe it gets bumped up to 3, then while hiking maybe it is 5 while running it gets bumped up to 8/9 and if it is struggling because of skin color or other reasons maybe it kicks in extra gear and goes to 10.

I recently sent a private message to a Garmin employee asking for clarification as to why Garmin uses different calculations depending on activity.  This is why you read countless post that says my cheap $30 watch, AW5, Fitbit, etc. works fine.  As far as I'm concerned, heart rate is heart rate.  If I'm maintaining a steady HR of 145, it shouldn't matter what activity I'm doing or if I selected the run, bike, cardio, or hiking app.  It should read 145, but this is not the case and there has to be some reason Garmin chooses to do so.  As far as I know, this is only an issue when using the oHRM as I've never been stuck on a "capped HR threshold" using a strap.  If and when I get a response, I'll post the explanation here.

I believe ForeKing explained it rather well, and the document he linked, too. The watch simply measures the HR as it is, but in some cases it needs to adjust the algorithm or the light intensity to compensate for the different conditions at each respective activity. In some cases, more ambient light may enter under the watch, than at other types of activiities. And at some activites you have more shocks (running, jumping) or arm motion, or more intensive blood pressure changes, than at other activities, hence the need to tune up the optimal sensitivity of the OHRM to each type.

The activity-depending algorithm also changes the frequency of measuring the HR. While at rest, or at activites with slow pace changes, longer intervals are suficient, and needed to save the power, at other activities, you need to measure the HR quite frequently to have sufficiently detailed HR report.

tess said:

countless post that says my cheap $30 watch, AW5, Fitbit, etc. works fine

My personal guess is, 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, because the heavier models (usually the more expensive ones) simply move more on the wrist, and it is more complicated to get a fit suficiently firm, and in the same time not too tight, to avoid limiting the blood stream, while not moving.

trux said:

The watch simply measures the HR as it is, but in some cases it needs to adjust the algorithm or the light intensity to compensate for the different conditions at each respective activity.

I respectfully disagree.  I understand the watch will use more power if you're scrolling through more data fields, have more sensors connected, using maps (as I do occasionally on my 945), etc., but calculating HR (sampling rate) should be the same regardless of the activity chosen.  In the example ForeKing gave while hiking, their HR didn't climb over 125 as if there was a "cap" set for that activity.  I've hiked many times where my HR exceeded 125.  If I chose the run app during those hikes, my HR would display correctly.  Because there are many variables between users, changing the algorithm on HR based on activity only adds additional challenges to the oHRM.  If you were to use an external strap, it wouldn't matter what activity you were performing or what activity profile you selected and the HR data would be more precise.  So why change the algorithm when using the oHRM based on activity?  The HR sampling rate should be the same for any activity regardless if I'm jumping around or changing pace.  Let's say the algorithm for the walking profile is "capped" at 110 bpm.  That may work fine for the two of us, but what about someone who's overweight starting out on a fitness program and their HR while walking is currently 120+?  It should read 120+ for that person and not stay at 110 just because they selected the walking profile don't you agree?