Sadly it is back in the box ready for me to return later this week.

I have also strength trained with my 5x and found similar with the wrist hr reading a very low or inaccurate bpm.

when walking or running it's seems fair,y spot on. I have used the onboArd hr occasionally when running but usually I will sync with my hrm monitor for the extra run dynamics it affords.

Most wrist HRM do not do good for lifting/weights IMHO. I have had the similar issues with my Fenix 3HR. Its contact based. Need to ensure that the watch is worn tight on the wrist. Why didn't you try with an external HR belt as opposed to returning it?
I have grown to use the Fenix for everything. I am not too crazy about HR, but I guess the calories etc all take HR as a parameter. So Garmin better get a fix soon

Optical HR is notoriously finnicky during sports activities. It's great for some people in some situations, and it's unreliable for other people in many situations. If your Fitbit works reliably for you, then congratulations and hold on to it. Weight lifting and rowing and activities that cause you to flex your wrist are supposedly extra challenging for optical HR.

Screeen brightness - you can set the amount of backlight from 10% to 100%, so that might help.

As for the size of the watch - caveat emptor.

Not sure what the reason for this post is. Initially, I thought it was some sort of boasting about how much exercise the OP does because there is no reason to mention it otherwise. I mean he wanted to say he was taking his watch back because he doesn't believe it provides good HR values. Perhaps one of the many and I stress many other threads would have driven home the fact the WHR is only really good for non-activity based HR. I find it equally strange because the OP has a chest HR monitor but didn't seem to use it.

Then even after all the complaints about the inaccuracy of the HRM and the "many issues" he reckons if it's cheaper and the firmware is updated he'll buy it again.

Sounds like someone who didn't research their purchase and is suffering buyers remorse.

I personally cannot understand why someone would spend all the money on this and not have a top end HRM as well. It gives you more dynamics making the watch more functional and obviously chest straps are what you use if you want accuracy.

Why buy a 700$ endurance sport watch to lift weights with?? Duh. 5x is for outdoor GPS activities and endurance training. Damn good watch. I've had them all and it's the best. Get a HR strap if you want HR for weights!

Wow, harsh crowd, I was not boasting, I'm sure there are lots more people that do far more training than I. I was simply trying to set some background context to what I was doing. I have a Polar watch with chest strap that is my go to, however I don't like chest straps for everyday use as they cause skin irritations and rashes. I was hoping someone would say something along the lines of, mne was off too until I did this.... I really want to keep this watch.

I purchased this watch, (not that I have to justify my purchases) as an all around fitness watch, from what I read it as great data collection and matrixes to gather as much info as I can. I know it's an outdoor watch, I don't expect the GPS to work while on the treadmill or strength training, however I DO expect the HRM to work while indoor with any activity. I'm a software engineer, I sit on my butt all day so I want to monitor my activity. I do expect a wrist HRM to work, I've had two Fitbits HR's and they work, they are not as accurate as a chest strap but they are consistent. My current Fitbit HR 2 is consistently off from my chest strap, not by much but it is off, however the key word is here is consistently. I use the reading as a relative measurement not an accurate measurement, that way I can still get the feed back on my intensity.

On my outdoor experience with this watch, yes I did test it outdoors, but I don't live outdoors all the time so I want it to handle more than one type of thing. I did find that the millage, pace, gps and steps were accurate, but again the HRM completely off.

I heard back from Garmin on this issue and they asked me to test some things, this was my response to them.

Thank you for the feedback, I had seen that link before, however because I really wanted to keep this watch I unboxed and tried again this morning.

Tuesday is my HiiT and Treadmill training day, I tried the Fenix 5x at different positions but again the readings where unreliable.
Mostly 80% of the time it stayed 100 bpm or below, my chest strap was reading 187 and my Fitbit was reading 179 at some of my high points.
I saw the odd spike at 126 and once at 139 on the fenix but then back to 84 the next second. I did notice that there seemed to be more spiked reading with more exaggerated movement, maybe there is an algorithm based on movement and heart rate sensor.

The most odd reading was during my cool down between HiiT and Treadmill workout, I was clearing my work area getting ready for the treadmill, when a glance at my Fitbit reading 142 and the Fenix read 156? I really do love this watch, it as everything you could possibly want in data gathering but I can justify 700 with the HRM so far off, sadly with a heavy heart I have to return.

The facebook 5x group has a harsh crowd! Say anything bad there and it goes to hell! I really don't like that - at the end of the day its a bloody watch not the first born!

I found I had to let the heart rate settle else would sometimes get odd readings. By settle that was adjust the tightness to 'ride' tightness and then let it get settled for a few minutes. Else I'd find it would sit with low HR then go crazy high or start high then do reverse after a couple of miles. After that its been pretty consistent.

I have a BT strap - keep meaning to use that to see if much different. Though to me it feels (once i settle it) about right for what I'm doing.

Lol @ harsh crowd.

Hey look if it ain't working for you then it ain't working. No dramas.
I'm not sure if two hrm side by side are going to interfere with each other and as with anything it's unlikely they would both show identical hr at the same time simultaneously together.

You could always stop mid workout, put your fingers on your wrist and count your pulse for 6 seconds and multiply by ten. Just a thought.

Used my 5x and garmin hrm at crossfit earlier. This was the trace. Early part was warm up and strength part. The latter part was the work out and the hr was obviously much higher.
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