Heart Rate Way Wrong

Here we go again...

There are countless threads about optical wrist hr monitoring around these forums.

Here’s an example:
https://forums.garmin.com/forum/on-the-trail/wrist-worn/fenix-5-5s/1453751-fenix-5-report-too-low-heart-rate-at-any-intervall-training

Here we go again? Not sure what you mean by that, but if you're implying that I don't understand the limitations of optical HR, then slow down and please carefully read the following.

1. I've read the posts about HR errors. They are a mix of understanding of the issue and misdirected replies about the tech itself.
2. The optical HR errors on my Fenix 5x+ are not the result of a property limitation of optical HR itself.
3. There is an error with the actual HR reading accuracy that goes beyond the intrinsic spec limits of optical HR.

The problem is not optical HR. The problem is an error, bug, data transformation, or implementation issue.

Is this more clear?

I've owned 5 devices that use optical HR. Three were from other makers (Fitbit, Jawbone way back, TomTom) and two Garmins.

All of these devices had adequately usable HR, with plausible error of +/- 4-7% or so.

My last device was the Garmin F3. Its optical HR accuracy was much closer to actual than the F5x+ is.

What's happening with this device is not a feature of the inadequacies of the type of tech used for HR. I have used optical HR thousands of times over years and am extremely familiar with when, how, and by how much those devices' readings varied.

This is an actual, real-world bug.

Ok.

Ok.

Cool, glad you agree.

I just worked out with my 4-year old TomTom multisport and my brand-new 5x+. I'm reading the data from both devices. The TomTom data looks both more sensitive to the intervals of the workout and the data itself is obvious closer to correct. But, you know, it's the optical HR that they *both* have that's the problem.

The 5x+ is turning out to be a stinker. There's no way around it. Sleep data is totally incorrect, too. What's next? North is "northish"?

Time to dig up the receipt.

I definitely agree! The optical HR is very poor. A lot less accurate then my Fitbit Surge. The Surge seems pretty good up until 130-140 bpm, after that it gets pretty bad. The Fenix is bad from the start. Might have something to do with the weight of the watch? I usually use a chest strap for workouts, but sometimes I don't have it with me. I noticed that if, before starting a workout, I restart the watch it seems to help, somewhat.

As far as sleep tracking? It's a joke. Not much more to say about that.

I won't go into a discussion of which device/brand has the best optical HR sensor (or 'least bad' is probably more correct). I've owned a few devices of different brands myself over the years, and there has probably been differences between them, however none have been good enough to make them a capable tool to for training by pulse/pulse zones.

If the deviation is more than say +/-1-2% then I don't care whether it's 5% wrong or 50% wrong. Wrong is wrong.

But hey, if you're okay with an error of +/- 7% - then I guess you might find a device that suits your needs. +/-7% at 180bpm would mean that you are okay with the watch showing anything between 167 and 193 bpm. In my book that is not "adequately usable HR" as it crosses three of five pulse zones.

Wrist OHR is super for all day tracking, but when HR matters during exercise there's really no other way than putting on the chest strap.


By the way, this might be an interesting read:
https://www.acc.org/about-acc/press-...rd-chest-strap
http://www.onlinejacc.org/content/69...973.1553240516

Yes, I know it's two years old, but I can't remember that I've seen any revolutionary new products in that time, with reservation that the new Polar sensors might have brought something new to the table, but I haven't seen any evidence of that yet...

SAHO - agreed an error of that magnitude makes the HR useless to train by. Also Outside - yes I expect the issue you are seeing is the result of software implementation rather than hardware and raising it and returning logs to Garmin will help them revise the algorithsm - however the 5X is a very bulky heavy device which gives it inherently more problems to overcome with software in intense activity as it is more likely to move on the wrist.

SAHO - agreed an error of that magnitude makes the HR useless to train by. Also Outside - however the 5X is a very bulky heavy device which gives it inherently more problems to overcome with software in intense activity as it is more likely to move on the wrist.

I really think there is something to this idea. This has crossed my mind a few times. I wonder if the device is shifting too much or something due to the small inertial changes. I tried to semi-test this by adjusting the band tension but didn't find any differences. I think the problem with making it too tight could also be affecting the reading, so it's a poor test. Anyway.

Earlier you said there’s nothing wrong with the tech, but just poor software or even a simple bug.

Now you say it might be related to the sensor in combination with the physical properties of the Fenix 5X Plus and how different ways of wearing it might affect the readings.

Which one is it? Poor software or hardware?

Or may I suggest - software that is intended to compensate for limitations in the sensor hardware that just works badly?

Welp, this is my second post about this device and I'm starting to scratch my head about why I spent the money.

I worked out this a few mornings ago-- hard rowing workout. My HR was recording a BPM of around 90 -- way, way lower that it actually was. My actual HR was around 150-160.

Last night I took a really brisk walk, including up a long hill. 5X+ showed a heart rate of between 59 and 65. Actual HR was around 110.

So what's gives?

Any ideas about why this would be so far off? I selected the "row indoor" activity, obviously. I tried both wrists.

Between this giant inaccuracy and the useless (and very misleading) sleep tracking, I'm starting to think this device is no good.

? Things can't be this off.

Funny, I‘m just on a hike expiriencing exactly the same issue. HR drops suddenly from around 110 to 55 and stays there till i either disable an reenable the wrist hr in settings or reboot the watch. I posted already a similar report in this forum. I‘m using a chest strap already for other workouts, but did not want to use it for all day hiking....but it seems I‘ll have to...and I also know the downsides of wrist hr, but I did not expect those big problems....especially as it works pretty well in 24/7 tracking...