HR accuracy when not in activity

Its awful, in an activity it appears ok, but end the activity and the watch thinks you have been lying down for the last 2 hours. Just tested it lifting some weights, Bluetooth strap to phone showing as 140bpm, watch managed to record 89bpm!!

Hello all.  I would recommend rebooting the optical heartrate sensor by performing a hard reset of the watch.

To perform a hard reset, press and hold the power button on your watch.  Ignore the "Power Off" question and the assistance alert (if applicable) on your watch, just continue holding the power button pressed down until the screen goes blank.  Once this occurs, you may release the button.  Allow the watch to sit powered off for a few seconds, then you may power it back on by pressing and releasing the power button.

You can also refer to the FAQ below for more information on this:

The Heart Rate Sensor on My Garmin Watch Is Not Accurate

Hello and thank you for your answer. Unfortunately, the problem persists.

Today i did a Zwift ride with a band and during the training i could see 135hr in Zwift and still 75-80 in the watch. I started an indoor bike activity and about 1min later the HR in Venu2 was similar to the one in Zwift (135-140). I left the activity for a while and after about 15min i stopped the activity in Venu and the hr went to 85 while stil 135 in zwift.

It seems like the sensors is acting differently while in an activity but the problem is that these measurements are a bit useless unless in an activity.

Regards

Yeah something is wrong when not doing an activity. Reset as described but reading are miles off what they should be. 

Please provide the requested information below:

1. Do we have your permission to view/access your Garmin Connect account to investigate further?
2. What setup are you using to see that the band is measuring differently than the optical sensor on the watch?

1. Yes

2. Tried different methods, 1 - Garmin HRM monitor direct to Garmin edge 530, over 60 bpm difference 2. Polar HRM to mobile (same outcome) 3. Polar to Edge 530 same

1. yes

2. HR to PC via BT or Ant+ / HR to Garmin Edge vs Vivo2 without activity the difference is about 20 to 60 (lower in vivo). With activity started, HR is about the same.

 doing a ramp test on trainerroad 

New record 89bpm difference!!!!!!

Exactly the same thing here. Unless I'm recording an activity on the watch, the HR readings are non-sense, specially indoors on the bike trainer. I'm typically above 160 during Zwift races / workouts, and the Venu 2 shows 80-100. Can find a couple of examples if needed.

Strangely that when going by bike outside the values are way more inline, and even acceptable without starting an activity, the problem is localized to indoor, at least in my case.

What I'm doing recently while on the bike trainer, I connected the watch to my Chest Hearth Rate monitor, start an indoor bike activity so it gets the readings from the HRM, and at the end I just delete the activity, so no duplicates. In this case the watch takes the external reading for the duration of the activity, even if deleted.