Heart rate sensor priority if external one is used

Normally, if everything is working properly, external HR sensor takes precedence over the built-in OHR.

To compare OHR with external strap you need the VA3 to use the built-in sensor and another device to register the strap data. The VA3 itself cannot register two heart rate data streams.

There's an IQ data field called Auxiliary Heart Rate that allows you to record data from a strap as a secondary stream and save it to the .FIT file. I used it on both my 235 and 735 and it worked great but unfortunately the developer hasn't updated it to work with the VA3. I emailed them twice about adding support for this watch and received no response.

It's a shame because it's a great resource. If it's not updated again after the 645 comes out I might fork it if the original developer still doesn't respond.

Hi, thanks for feddback.
It's nit an issue how to record data becasue strap ca work also in standalone mode and store data in build in memory. It's Polar OH1 strap with optical sensor but much more accurate than wrist one.
The problem is how to extract it and compare it...
??????
Is there any way to confirm that garmin connect shows graph from external strap?

Is there any way to confirm that garmin connect shows graph from external strap?

Just by looking at the graph? I don't think so, although if you are very experienced in that matter you might recognize some siginificant patterns, as the OHR graph would usually have more imperfections than a graph from a properly functioning strap. But there is no definitive information to the source of HR data anywhere in Garmin Connect.

Not by looking at the graph :)
I thought that maybe is noted somewhere in Garmin Connect but ok.
I will check it today inndifferent way. OH1 can simultaneously send heart rate to watch and store data internally. I'll leave wrist sensor on an then it will be clear which one is stored by watch.
Based on review I've wrist sensor is loosing accuracy with activities with many HR peaks in short t time whic is exactly an issue playing soccer.
Thanks

All Garmin watches with oHRM's will default to a paired chest/arm strap if capable. Prior to starting an activity you should be getting an alert on your watch that says external HR connected. Is this not happening for you? If you want to use a chest/arm strap outside an active, go into settings and you can manually connect. Is your concern that the chest/arm strap is losing it's connection? If that's the case, the watch will switch back to the oHRM automatically if turned on or otherwise you'll have no HR reading at all. If your chest/arm keeps dropping off and switching between the two, there's no way of knowing switch readings came from switch sensor.

The above does't appear to be true, at least on my VA 3. I did the following. Put on chest HR strap (Garmin HR Run). Make sure in Settings->Sensors And Accessories that it is connected. Turn off OHRM from Settings->Sensors and Accessories. Note on main watchface Simple Heart that HR is not being displayed. Check again to see if strap was connected, it was. Check a few minutes later, strap had disconnected (haven't had issues with it disconnecting in activities). Connected again. A few minutes later removed strap and turned OHRM back on. Synced with Garmin Connect Mobile. The heart rate chart for the day shows a gap for the entire period when OHRM was off.

I didn't run a specific test for this but I seem to recall in the past when using a chest strap, the heart rate shown from within a sports activity doesn't match exactly the heart rate shown for the same period in the general heart rate chart for the whole day.

So it looks like on VA3 at least, an external strap is only used from within activities, not when in general activity tracking mode outside any sports activity. And it is only used for the heart rate for the activity itself, while the heart rate chart for the whole day always uses the OHRM.

Any thoughts?