955 Heart Rate drop when burping?

I think it's normal.  I've experienced this for years with several Garmin watches and chest straps whether on a treadmill or outdoors.

I see the same thing, wrote about it somewhere on the forum. Still don't know whether this is a HR strap artifact, or a real thing. But the data is very real.

All I can say is LOL

As far as I tell, it's a chest strap issue. Graphing both HRs (in Intervals.icu) shows the chest rate drops but the wrist doesn't. I suppose the wrist rate might have some cleaning done to it.

Classic

Andrew Coggan in another (Slowtwitch) forum: 

"Yes, it happens to me (and probably almost everyone else).

Eructation (burping) is under control of the parasympathetic nervous system. Thus, when signals are sent to the muscles controlling this action, there is some "spillover" to the vagus nerve, which provides parasympathetic control of the heart. The result, as you've observed, is that your heart rate (and blood pressure) tend to fall when you burp, even when you're exercising. (The same also happens during micturition, i.e., when you urinate...which explains why you might feel a bit light headed and sway a little when using a urinal.)"

https://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/BURP!!!!!_While_training_and..._P1253248/

In which case you would expect the wrist HR to also be affected unless, as I said, it has some cleaning done to it.

There's always some "cleaning" done to any HR measurement, just because the time between individual heart beats change a little always (that's what HRV is about). So the question is just how long the HR analysis window is. And I agree, that window is definitely longer for wrist HR, because optical HR measurement from wrist is noisier, and that window is probably long enough to hide the effects of burping. But even the strap HR has a smoothing window also, just a shorter one (and those windows are probably not constant in length, because it's enough to smooth the HR over a certain number of heart beats).