chest strap versus wrist monitor

Oof, Better don your flame retardant suit. This comes up often and people get uppity about it.

Anyhow, there are a millions thing that will affect the reading on your wrist heart rate reading since it is using light to measure blood flow. Anything from skin color, tattoos, location on your arm, how tight the watch is on your wrist, and any combination.

There is also a thing called cadence lock where your heart rate will match your cadence. Keep in mind that you are a large meat bag with liquid inside.

Basically anything that can alter the blood flow, or perceived blood flow past the sensor will affect the reading.

For me it is good enough for the 24/7 monitoring. It is good enough when I am out on a walk or a pleasure bike ride with the wife.

If I am going to be doing anything more then i put on a chest strap.

Just my 2 cents, your mileage will vary.

I've owned 4 Garmins with heart rate sensors, and all have been hopeless with anything but resting heart rate, the Fenix 6 Pro which I've recently purchased seems to be the worst of the lot (not helped by the latest firmware).

My Fenix 5+ was accurate in a resting state compared to my heart rate belt over a 5 minute period within 1 BPM - the 6 Pro is +/-5 from the belt. The Forerunner 245 is also belt-accurate in a resting state.

I've seen 50-60 BPM discrepancies often - walking where I generally am below 90BPM I've seen it go up to 155 BPM (I run lower than that!), doesn't matter how it's worn (I'm two fingers up from the wrist bone always), or how tight, and also huge random swings when I'm not doing much of anything any it should be below 60 BPM, but reporting 100+.

The Fenix 6 does seem to have the worse heart rate of the lot, but even with earlier Garmns I found an external heart belt essential for anything other than resting heart rate.

So yes, its' very possible, and in all honesty this is probably normal rather than the exception. There is a very good reason why Garmin / Polar / Suunto all sell external sensors...

Or flame retardant chest strap.

Yes, it can be that bad.  But it's all your fault: Too much wrist hair: Not enough wrist hair; Wrists are too small, or they could be too large.  Maybe your blood vessels are the wrong size?  It could be anything but whatever it is, it's absolutely not Garmin's fault.  They wrote a tiny disclaimer next to the product highlights for a $1,000 watch.

If this were a car, under California Lemon Law, a lot of us would be getting our money back or at least a new watch.  But it's software, so, you know, these things happen and it's OK.

One other cheery thought, I had the strap and headphones drop during a run, so even a strap isn't a sure solution.

Experiences vary. Some people have terrible experiences with the WHR, while for others it works fine. Mine has always worked "good enough", the charts it makes are a lot choppier and the accuracy isn't quite as good as with a chest strap, but it's close enough for me. Certainly not off by 50-60 bpm! Maybe more like 5-6 bpm.

There are lots of things you can do to improve the accuracy of the WHR - adjusting the strap tension, wearing it higher on you wrist, etc. But there will never be a substitute for the chest strap - chest electrical HR measurement will always be more accurate than optical wrist pulse measurements.v Which is why, as someone already mentioned above, the very brands that make these watches also make chest straps.

One common cause for OHR inaccuracy is the watch moving on your wrist.

When running, this can cause external light to enter the sensor in a rhythmic way with each arm swing, and the watch locks onto your cadence rather than your HR.

I find I have to have the band 1-2 notches tighter for accurate HR while running than I do for 24/7 monitoring. Positioning the watch on the fleshy part of the wrist, well away from the wrist bone also helps.

When worn with the band snug, I find the OHR pretty accurate, but I still use a chest strap when I am doing intervals, as the chest strap is more responsive to short changes in effort than OHR. For longer intervals, or steady state runs, I just use OHR.

DontGetTheSwiss said:

If this were a car, under California Lemon Law, a lot of us would be getting our money back or at least a new watch.  But it's software, so, you know, these things happen and it's OK.

No, that would be like complaining that your antilock brakes do not stop you in the wet as fast as they can in the dry. I know there will be a difference because I understand how antilock brakes work and the environmental factors which affect available traction.

RobCuadro said:

If I am going to be doing anything more then i put on a chest strap.

Which is exactly what Garmin recommend.

5135968 said:

There is a very good reason why Garmin / Polar / Suunto all sell external sensors...

And all recommend using chest straps for 'active' activities.