Hello, just had a garmin fenix 5x plus at at a bargain. I must say, I'm disappointed with the results. I've used both chest-traps and wrist-based HRs in the past, the data as some of you here already mentioned for high intensity workouts is basically uselless. I've watched DesFit's old youtube video with regards to concern in HR accuracy and thought that it should have been fixed by now via some firmware updates, but I dont think this is still the case. This might be more of a hardware (sensor) issue rather than firmware...
It’s not hardware nor firmware.
Some parts of the problem are due to how you wear it. By now most people know it should be snug and as far up your arm as possible.
But most parts it’s personal. I read a lot of review dcrainmaker makes. He has next to no problems with ohr while running but doesn have problems with cycling, I have it the other way around. Lot’s of problems with running, never with cycling.
With running I do get a lot of cadence lock. Tried different watches of different brands. I just gave up and use my cheststrap when doing intervals or don’t bother with heartrate to much when doing trails, or just running for fun. I know my body well enough. Ohr is good for resting heartrate which has some value.
The good news is I don’t have to spend 600 or more euros on a new Garmin watch with a newer sensor. It’s probable not going to give better result (and doesn’t have any new must have features anyway) So I’m still happy with my 5 years old fr 935.