Charge 6 gives wrong HR when using rowing machine

[Bilsky]

I have a rowing machine that I use regularly and I started noticing that my charge 6 recorded really high HR's when exercising. I started wearing a polar strap to test against it because it seemed so far off. 

For the same exercise sessions my polar strap accurately shows an avg HR of 112 with a peak of 122 for a 20 minute workout vs. 165 avg and a peak of 195 with charge 6. This same swing happens every single time. The charge 6 seems to work for other exercises like running but with the rower it's just awful. 

Is this simply to be expected because the charge 6 can't process the wrist motions of rowing accurately? It's really annoying to the point that I don't even want to wear it anymore when doing this exercise because it's so misrepresentative of the real data.

Moderator edit: edited title to clarity

[CrisVillaFitbit]

Hello and welcome back @Bilsky, it's nice to see you around the community.

Thanks for explaining your situation with the heart rate on your Charge 6 when using your rowing machine.

Rowing machine is not input as an activity in the exercise app, but your Charge 6 should give the correct heart rate, remember that to determine your heart rate, the optical heart-rate sensor in your Fitbit device flashes its green LEDs many times per second and uses light-sensitive photodiodes to detect these volume changes in the capillaries above your wrist. Then your device calculates how many times your heart beats per minute (bpm). This is the way all Fitbit devices track heart rate, which is different than the way other devices can track it, so it is normal if the heart rate varies between devices, but not that much.

I recommend you to restart your Charge 6 before your workout and let me know how it goes after that.