Heart Rate Sensor Issues

I noticed after the 13.10 update that mine was off too. I would be running and nearly out of breath and the watch is reporting 120 or around that. I fixed it by making the strap super tight when doing an activity. I am assuming it had to something to do with the watch sliding up and down my wrist ever so slightly that would mess it up.

Are you recording an activity at the time?  Lots of people here report that it's very inaccurate until you start an activity, at which time the sensor seems to kick into override and record correctly.

Has it always been wrong for you, or did it just start?

No, this is just looking at the watch heart rate monitor. I’ll try start an activity next time...

Right - this is a very common complaint on these forums, there are threads and threads of name calling, anger, upset etc etc due to this issue.  The workaround is to start an activity which will properly record your HR.

Cue the 50 posts of "This isn't acceptable for a watch that costs X, Garmin is rubbish, I'm moving to Apple etc" which will no doubt follow below.

what I've found with mine is if I simply select an activity with a HR display, but don't actually start the activity with the 'start' button, the HR value seems to work fairly well in that mode as well.  Haven't tested it a lot, but from casual observation it appears to be correct whenever I do a manual pulse check on my carotid.

Just same here

Okay, I guess that all makes sense. I do doubt the accuracy of the heart rate sensor daily if you need to start an activity to gain any sort of accuracy. Do we have a margin of error for the sensor day to day ? 

Yep, I have a similar issue. Took an easy run tonight and average HR was way high and higher than the threshold run I did last week. Seems to be intermittent bu I’m clocking over 200bpm at times, just not possible. 
struggling to find a fix

anything that includes tension on/around your wrists will degrade the optical HR measurements. Garmin recommends to have the watch further up the arm for optical to work. (2? inches up from your wrist 'ish)

That being said my old AW4 does a much better job at having correct HR vs the F6Pro. It is not perfect either though compared to a HR strap. 

My wife have tiny skinny arms w. freckles - and NO optical HR works reliable on her - inclusive the "external" optical devices like Polar OH1 etc. No matter where it is placed - it has patchy HR readings. The OH1 is fine on me though. 

So Optical HR is very much dependent on skin type - skin colouring - "size" and quite a few other factors. So I do understand why F6's have issues. But my AW4, is still, IMHO quite a bit better than my F6x Pro for me.

For many runs the AW4 is close to perfect - IF I do not do things like interval runs etc. Then the AW4 starts to lag and miss. The AW4 also needs to be worn for a while before you start your exercise to (I think / speculation) calibrate to your skin. 

I use.Garmin HRM Pro strap and Polar H10 as my main go-to straps. The Polar is much more comfortable to wear with the Polar Pro strap. The Garmin HRM Pro cuts into my skin where the "buckle"/"chafe protection" is - so I tend only to use it for shorter runs. 

This is all well and good but doesn’t explain why for the first month or so it’s been fine. It works ok when hiking, and biking but not running right now. I have done a full reset and to no avail.  It’s just not acceptable. Will be interest to hear what Garmin have to say