Sudden drop of HR when switching HRM Chest strap -> OHR Sensor

Not really sure if this is a bug from the sensor switching or if it is just the already mentioned inaccurracy of the FR945 OHR sensor during activities. I compared it once in a way where I had my FR935 connected to the HRM Tri and in parallel a FR945 on the other wrist in OHR mode. During the activity with increased effort (and sweating) the FR945's HR reading became more and more erratic, at the end undercounting by 20-30 BPM towards the HRM Tri.

I can't say if this is a specific FR945 problem or simply the fact the OHR has its limits especially if your wrist is sweaty and the watch starts to move around it during a run, which may lead to wrong readings.

I don't much see this as a bug either. Situation seems to be, switching sensors and OHR takes some time to get locked to "maybe the right HR" after being turned off... Wouldn't see that as a bug, what would the OP want to happen here?

If you just happen to wear the watch, then I can understand. The OHR takes times to adjust or learn the actual HR reading.

When you are already wearing the watch and with a chest strap, the watch should be smart enough to "learn" the current HR from either OHR or chest strap.

The sudden drop in HR is really so dumb producing inaccurate HR readings.

20-30 bpm drift is really such a big difference. Is that an anomaly or do you have a faulty strap?

So make an algorithm that when switching it wakes the old HR value and new HR value and calculates average from giving more weight from strap to OHR? Yes... That would nicely make it look nicer, but is it more correct? Dunno.

What does this matter? You aren't changing it during the activity, or are you?

And 20-30 bpm drift being big, well, it's OHR, YMMV.

hi,

70 is the initial value with which the OHR starts after switching source

drop in hr rate with hr belt can occur through signal short by salty sweat

happy & safe sporting

jmto said:

What does this matter? You aren't changing it during the activity, or are you?

It doesn't matter to you. It matters to others.

Like I said, the sudden drop in HR when switching source from Chest Strap to OHR is really dumb which can be avoided with a proper algorithm in the software.

DPSK said:

It doesn't matter to you. It matters to others.

Yes, I asked in which situation that matters to you, not saying that it doesn't matter to you.

As if it is done after the activity, it's just small beauty fix, that doesn't effect your data. Doesn't feel like real issue.
If it is done during the activity, then if you have HR saving strap, like HRM-Tri, you will get the proper HR data from it's storage when saving activity. Again, doesn't effect your data.

So in which situation this matters to you?

jmto said:

As if it is done after the activity, it's just small beauty fix, that doesn't effect your data. Doesn't feel like real issue.

Your current HR is 120 bpm. You save the activity and go into the main screen on the watch.

Your HR immediately drops to 70 bpm.

You don't see this a problem when you try to analyse your HR data? Isn't that a weird recovery HR?

I don't follow.. Main screen? So you have a watch face that shows HR? And you look at your recovery HR from there? Well, your recovery hr process is that is to blame here.

If you are interested in your recovery HR, you will pause the activity and take too many button presess to select "Recovery HR" and look the recovery HR from there, and then go back and "Save".

The old way was to press pause and wait for 2 minutes for the popup before "Save".