HR sensor accuracy
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Hi guys,
Very interesting readings here. Helps a bit understand my “bad HR sensor” impression since wearing the Race (titanium).
Here are 2 photos taken from the same exercice (small fitness) wearing Race versus good old Suunto 5.
I think I’ll try moving the watch up + resetting and I’ll see.
HR sensor is not 100% a major issue for me but when you put a lot of money on a watch that is supposed to work (and be better than the previous one) you expect something better.
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@duffman19 I can upload the manuscript if you wish. I have access.
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Garmin with chest strap suunto on the wrist no major abnormalities.
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Have my Suunto Peak Pro 9 since January 2024. Almost ever since the beginning, once every couple of workouts (very randomly) I have been experiencing horrible HR sensor accuracy. Let’s say I go for a run - I tend to have very high HR during cardio workouts, so my HR will usually be around 160 or more. Then, all of the sudden, my Suunto will start showing something completely false like 90 or 100. It makes the watch absolutely unreliable.
Below is my Strava screenshot from 25 km nordic skiing competition I participated in recently - it was very heavy workout for me, as you can see from the first couple of kilometeres… and then the HR sensor went down to 80 or 90. sn’t HR measurement one of most important things that a sport watch should do?
It happens repeatedly, randomly and makes the HR measurement, which is a really crucial feature for me, completely unreliable.
I have sent the watch to Suunto service - they said that they ran all the tests and everything works fine, so I should consider buying the Suunto chest strap (!!).
My boyfriend has a Garmin of comparable class and the HR works fine for him. I am extremely disappointed with both the product and the service - this is certainly not the quality I had expected from the brand Suunto. I am definitely not getting another Suunto watch ever again.
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@AnnaBi If HR is crucial, you need to use a chest strap. Wrist-based monitoring is garbage for sports, regardless of the brand. (It may seem to work at times, but the values are inaccurate, even if some models appear to perform better than others). The wrist-based heart rate sensor is simply not suited for sports but rather for daily tracking.
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@Ghost as this is true for Suunto, it isn’t for all watches on all brands.
My Epix Pro has really great HR accuracy, unless the software bug hits that prevents it from being. There is almost nothing to gain with a chest strap. I could show you examples, as Garmin records both external and wrist heart rate in the FIT file.
Suunto Race S
Garmin Epix Pro -
@2b2bff I think the reality is that the Optical heart rate sensor on watches in the world is not accurate enough to be comparable to a chest strap with a medical ECG cable.
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@SODIUM identical - no. Comparable and perfectly usable if you don’t need the last beat? Yes.
As an example: Threshold Run - Epix Pro against HRM-DUAL.
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@2b2bff said in HR sensor accuracy:
@SODIUM identical - no. Comparable and perfectly usable if you don’t need the last beat? Yes.
As an example: Threshold Run - Epix Pro against HRM-DUAL.Activity type?
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@Matúš Running, as I said…
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I think the fact is that OHR is not reliable for all people and in all circumstances, whereas a chest strap is. One person could use a Garmin with great results and yet be no good with a Suunto or Polar. Someone else could have completely opposite results. The measurement method depends on too many things to be entirely accurate for all people, all of the time for all activities.
For me, Suunto works well, but I still use a chest strap for running and gym activities.
If accuracy matters - and it seems to for most people - buy a chest strap and stop worrying.
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@2b2bff, sorry, I’ve missed the “Threshold Run” tag.
Is this true even if you’re using poles (if you have ever tried)? -
@2b2bff I disagree. This has absolutely nothing to do with Garmin or the EPIX. You’re lucky because your wrist perfectly fits this model. You’re lucky because your running form is compatible, and you’re lucky because your arm movement isn’t excessive enough to disrupt the measurement.
I invite you to South America, deep in the Amazonian forest, where you have to run through thick brush, cross muddy streams, and then we can talk again about the reliability of wrist-based heart rate measurement. For some individuals, it may work in specific conditions, but certainly not in multisport activities—especially not during intense efforts.
On the other hand, a chest strap provides accurate heart rate measurement in any situation and for all body types, regardless of size, age, or weight. That’s why I’ve explained that wrist-based heart rate tracking is not reliable. It doesn’t work consistently, no matter the brand or model, with only a few morphological exceptions.
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it’s pretty extensively documented that suunto race (original) was worse OHR than competitors in the same scenarios. both desfit and dc rainmaker reached this conclusion. as it has the same gen sensor as the 9PP, you can assume OP has the same issues.
the race s has a upgraded sensor with better results. if the race (original) and 9PP had decent OHR they wouldn’t have updated the sensor. yes, OHR is limited and never as good as a chest strap, but that doesn’t stop there being bad OHR sensors. stop gaslighting OP…
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@Ghost agree to disagree.
I didn’t say wrist heart rate is perfect and a chest strap is unneeded und all circumstances. I’m just a bit allergic to the “wrist heart rate will always lie to you and you need a chest strap for anything that is more than a guess” approach. Simply because it is not true. If you are a casual street runner and don’t aim for perfection wrist heart rate might be all you need - if the values suit you.
Sure chest strep will always be more accurate, but also it is more of a hassle when you add a vest or run for longer periods. And it is another device that could fail.
TBH if I ever happen to run in the jungle, I don’t think I wouldn’t care about HR that much…
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@2b2bff Sure thing. But @AnnaBi said HR was crucial, so I responded: if it is crucial, it shouldn’t be based on casual, approximate data—it should be measured with a chest strap. And I always wear one during sports, to the point that I don’t even notice it anymore, enjoying ZoneSense, running in the jungle or doing jump rope.
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@dankcushions It’s well-documented that wrist-based optical heart rate (OHR) has limitations, and yes, some sensors perform worse than others. The Suunto Race (original) using the same gen sensor as the 9PP did get criticism for its OHR accuracy, and the Race S upgrading the sensor suggests Suunto recognized the need for improvement. That said, OHR performance also depends on individual factors like wrist physiology, fit, and activity type.
No one’s denying that bad OHR sensors exist, but calling it gaslighting is a stretch. If OP needs reliability, a chest strap remains the best option—no wrist sensor will consistently match it.
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I tried the OHR Race S and it performed incredibly well. -
No one’s denying that bad OHR sensors exist
@Ghost right, but that’s not what you said:
Wrist-based monitoring is garbage for sports, regardless of the brand.
This has absolutely nothing to do with Garmin or the EPIX. You’re lucky because your wrist perfectly fits this model. You’re lucky because your running form is compatible, and you’re lucky because your arm movement isn’t excessive enough to disrupt the measurement.
because it DOES have a lot to do with the epix, which has a comparably good OHR sensor, giving serviceable results to a higher portion of users than the Suunto 9PP / Race, which has a comparably bad OHR sensor.
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@dankcushions Thanks for the clarifications. However, I stand by what I said—OHR is garbage for sports across all brands and models, except for a lucky few whose physiology happens to align perfectly with their wearable for somewhat decent approximations. My point was simply in response to someone stating that HR is crucial. If it’s crucial, then you cannot rely on OHR for sports, regardless of the brand or model.
