Hi,
I have been using the FR 645 M for since April 2018 and in the last 3-4 months have been facing issues with Wrist HR accuracy especially during indoor or gym activities. Whether I am on the Eliptical, doing HIIT, Cardio or Strength training, the HR recorded is extremely low and barely going over 100. I tried comparing this with HR on the gym equipment (like treadmill/eliptical) and also by using a chest HR strap. The variance is huge with max avg HR on the FR645 only around 100 bpm while the same using the chest strap is closer to 160 bpm.
Surprisingly, any the wrist HR during outdoor activities like running or road cycling works perfectly fine. The same is the case on a routine usage or while resting/sleeping; the HR is accurate and comparable to actual or with other devices. The problem is only when i select an indoor activity.
I have reached out to Garmin support center in Singapore and also in Taiwan but they have been unable to either identify the issue or resolve the problem. I have sent the .FIT files to Garmin 3-4 times with no outcome. They keep saying that I need to wear the watch properly and refuse to accept that there is any problem. I have also tried to update software, reset the watch and now cannot think of anything else.
Really appreciate help from anyone.
Regards,
B.Parikh