HR Dynamic Source Switching - what is the point?

There are occasions when the watch looses the connection with the strap (or strap looses contact with the skin). On those occasions dynamic switching uses wrist hr until the strap hr is restored. 

And yes, it happens occasionally for short periods of time.

Okay. Not sure I have ever seen a drop out on any of my garmins to be hoenst but that explanation makes sense I suppose.

I thought and asked the exact same when this originally came through via beta release! The main benefit I see is that by disabling source switching, OHR is finally switched off when using a chest strap during an activity. This prevents unnecessary and excessive battery consumption 

I mainly notice the strap hr dropouts because then you loose breathing rate, which is easy to spot in the graphs. Sometimes I think it might be because of electrical interference, because I have one running route where I often loose strap hr for half a minute in the same spot. ANT+ signal is not very strong and neither is heart's effect on the skin.

Hooray, Garmin has finally done it! I'm turning the feature off and finally I won't have my OHR active when I'm training with the strap! I've already tried it. This feature was really getting on my nerves. Once again, Hooray!

Garmin have published a quite thorough explanation the last week or so (a user in the Fenix beta forum found the link):

What is Heart Rate Dynamic Source Switching?

https://support.garmin.com/en-US/?faq=Nf8r6ApX4d9lX0G0flEsVA

Observe that only select Garmin straps can supply the information back to the watch for dynamic switching to work (or they choose to ignore everything else):

"Switching sources based on the quality of the heart rate signal during an activity requires the use of a Garmin HRM-Fit, HRM-Pro, or HRM-Pro Plus heart rate monitor along with a watch from the compatible watch list below."

The information page is long, so keep scrolling past that list for the full text... They eg. mention what we normally call 'spikes' in the HR-curve during the first minutes of winter exercise - before sweat has made a good skin contact.

I, with a Polar H10, am just glad that they finally provided a switch to turn the thing off. The last couple of firmwares have probably suffered needlessly from Garmin OHR/Strap experiments.

What you write is consistent with my experience. I also have a Polar H10 and switching sources just didn't work well for me until now (with the previous firmware). So I very much welcome turning off the battery guzzler that has brought me almost nothing.

I have the same question. Also why the limited set of HRMs Garmin HRM-Fit, HRM-Pro, or HRM-Pro Plus? Garmin HRM-Dual is not on the list. Why? Is it that bad? Is it too cheap? Not to mention other vendors.

Something is cooking there and the users are taken for ride by Garmin.

Since release the watch worked fine without this "feature". Only now they added it at the cost of degraded performance from OHR.

It is clear now that Garmin has o intention to fix the OHR.

Extremely disappointed by this move.

My guess is that some HRMs don't provide data to assess the quality/reliability of strap HR.

Also (again just a guess) Garmin might use dynamic switching info to improve optical HR, since now they get both optical + strap HR data from every person using dynamic switching (they now store in the fit file wrist HR, strap HR, and HR produced by dynamic switching). So they will have a lot of data showing where wrist HR fails and how new firmwares affect it.

I had a bad experience with the Source Switching while cycling today. I had it on with my HRM Dual band, which is not listed among the compatible ones. When I started the activity the HR was above 160 BMP. I stopped, stopped the activity also, went to settings and turned off the Source Switching. When I started the activity again the HR was at 90 BPM, something logical.

For my cycling activities I use my 955 on the handlebars. I intuit that being there the OHR took any value (the wrong one of +160) and as I don't have a compatible HRM (mine is the HRM Dual) it didn't compare the values. I don't know, I guess. For this reason when I turned off the Source Switching, it took directly the HRM with the correct value.

I comment this in case someone else can benefit from the experience and in case someone has a HRM that is not compatible to take into consideration to turn off the Source Switching to avoid erroneous data. The Source Switching did not work well for me, the good thing is that the option to turn it off is available, so everyone can choose to use it as they prefer.

I tested it using v19.18.