Worth remembering about wrist worn HRM - Bridge to 10K

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Worth remembering about wrist worn HRM


It’s not the brand of the device but a problem with the technology:


If your heart rate looks wrong it probably is. My heart rate walking to work today was measured as over 180. Yes it was uphill and I was walking fast, treating it as cross training. But I’m 59 years old and the idea that I could sustain a heart rate of over 180 for twenty minutes with no discomfort is just absurd. Normally the same walk at the same pace takes my heart rate to 120 or maybe 130. I suspect the 180 was my cadence not my heart rate: the article explains how the technology causes the two to be confused sometimes.

11 Replies

When I upgraded my Garmin I considered getting a chest strap but thought I'd see how it performs without. So far I'm very happy with it. I've got a rough idea of where my heartbeat should be so for me it's just a training aid. I wouldn't consider using it for any sort of medical diagnosis.

ArthurJGGraduate10 in reply to SlowLoris

I don’t think I said anything about medical diagnosis but the point is it can give spurious readings that are unhelpful for training too. Strava is telling me to ease off as I’m overtraining this week, but that’s because of one faulty HRM reading that has distorted my effort score for the whole week. That’s the second time that’s happened and I would be resting when I should be running if I wasn’t aware of the fact that every once in a while it will give an off the wall ridiculous reading. Given a number of posts here where people have asked about wrist worn HRM and clearly been unaware of the likelihood of daft readings from time to time, I thought the link was worth sharing. It’s not a question of which model or brand: it’s an inherent issue in ALL wrist worn HRMs.

SlowLoris in reply to ArthurJG

It was the article that mentions using wrist HRM in Clinical trials. You're quite right to post it. The research it is based on is focussed on Fitbit type activity monitors. The one they use is the Vivosmart. Personally I think there's a big difference between that and a dedicated running watch.

ArthurJGGraduate10 in reply to SlowLoris

True the article did say that but it also goes into some detail about WRONG (not imprecise or inaccurate) readings and it makes it very clear that Garmin uses the same technology with the same flaws. Yes there are differences between a Fitbit and a dedicated running watch but the HRM technology is NOT one of them and if you are using it to monitor your training you need to be aware of that.

SlowLoris in reply to ArthurJG

Yeah I get that. I read the original research as well as the newspaper article.


Yes when I first got my Garmin I set it to alert me when my heart rate reached 160bm. I wore it at my parkrun and it kept beeping at me, forcing me to walk in fear of my heart. When I posted on hear there was a unanimous response to switch off the alert and go by how you feel. 💗💓💔

Sandraj39Ambassador in reply to Dexy5

Each to their own, I guess but they are not for me either. I run by feel; push on if I feel good, slow down if things feel hard. Fartleks for increasing pace and 'slow and steady' to build endurance. 🙂

Dexy5Graduate10 in reply to Sandraj39

Yes I stopped the alert after that first run.


DC Rainmaker, who reviews a lot of running gear, says Garmin Fenix series (which I have) compared well when tested against a chest strap worn at the same time, but the watch was slower to bring the heart rate down when reducing effort. Apple claim their watch is respected by medical personnel as do Fitbit.

It seems individual physiology comes into it a great deal, all wrists are very varied! I also had one point where my garmin would flatline unless I restarted it at the beginning of this year, but that seemed to fix with software updates so must have been a programming issue rather than a hardware one. I've actually found my own garmin wrist readings to be fairly accurate (at least, rhr and max—presumably there's a big error margin during activity) and I've not experienced cadence lock. But that's clearly an issue for some people, related to the ease of pulse detection and their movement. There are some strong disclaimers from Garmin, it's promoted very much as fallible and for use only as supporting information. It would be very unwise to use wrist monitoring for anything medical. That said, I find it accurate enough to train with, even for intervals, which is a bonus I didn't really expect, though I may be in the minority there!


OK, I accept that wrist worn HRMs may be inaccurate. So for me, the key question is 'what's the risk?'. If my body is telling me I feel fine but the HRM is giving an anomalous high reading, I may ease off slightly and check if my HR goes down, so no big issue there. If I'm gasping for breath but my HRM tells me my HR is in zone 2, then I'm going to listen to my body and ease off and probably investigate.

So personally, I don't see any real issues that outweigh the benefits of sifting through all the data and analysis that Garmin Connect provides. This is a hobby and having the stats, for me, adds to my enjoyment.

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