Time for some more comparison data and discussion.

This time, heart rate measurements via the old-fashioned chest strap versus the newfangled optical heart rate.
Garmin with the fenix 5X and its Elevate sensor oHR versus Suunto (Spartan Ultra and, for once, Ambit3 Peak) chest strap versus Suunto Spartan Sport WHR Baro and its Valencell oHR sensor.

Let the games begin… and leave all hope for something so close to science getting results you should consider as exact :-p

Garmin fenix 5X oHR vs. Suunto Spartan Ultra HR Strap

Remember the runs and hike in Italy that gave a good insight into the bad satellite reception in dense old cities? I also used those for some HR comparison data…

Rome, My Heart

 

Clearly a lower sampling rate from the fenix 5X (or more smoothing of the data), but that’s not exactly a problem. Some spikes where the chest strap recorded lower heart rates are noticeable (at 30′ and at 47′); these seem quite typical for oHR sensors.

Overall, I’d say that the HR (in a qualitative view at it, not a statistical analysis) tracks alright, given the limits of the technologies…

Firenze, Andante

Walking in Florence found the GPS very jumpy. But, what about HR?

Less bounce could mean that oHR has an easier time of it. Less exertion, lower HR, no sweat, though?

No, I guess “easier” is not what it is for oHR. Neither is it ideal for a chest strap-recorded heart rate that is indicative of anything, though.

(The chest strap may have an advantage here, given that it can record heart rate variability and use it to indicate recovery status. On the other hand, going for a walk with a HR strap on isn’t the most comfortable thing to do, and just for an approximation of how intense an activity this walk was or wasn’t, oHR is much more comfortable and, in the average, okay in spite of the spikes. The swings are again noticeable, though.)

Firenze, Adagio (Running)

Faster again in Florence, gone out for an early-morning run even while feeling the onset of a cold. And now?

The oHR didn’t seem to like that very much. Problems at the beginning are not unusual, and later it did track the chest-strap-recorded HR better. It’s still more of a statistically average fit that might come out of it, were the same run/measurement to be repeated many more times, than anything that looks exact.

We are talking about differences that are typically in the range of 5 heart beats, if that, however. Meaning, if someone really wanted to be able to tell which recording is truly more exact, it would take running with an ECG for medical purposes (or tested to standards sufficient for that) and a statistical analysis.

The very thought drives my heart rate to greater differences than what looks likely to have been the measurement error.

Mountains of a Heart Rate

What about a hike, adding some strenuous climbs. bouncy ascents (and bad weather)? Plus the Suunto Spartan Sport WHR Baro with its optical heart rate sensor?

Well.

The result is an image of just why heart rate measurement, clear as HR seems to be, is not easy to evaluate.

Look at the beginning of the recording, and the (blue line) fenix 5X obviously had more issues; the chest strap (here connected to an Ambit3 Peak) and the Spartan Sport WHR Baro oHR are closer to each other.

Looking at it in more detail would be a great example for the possibility of lying with data, though: If I showed the two Suuntos only, the two heart rate recordings would differ as much and more as those between fenix and Spartan did in the above examples from Italy.

Later on in the recording, there are further examples of the fenix 5X Elevate oHR sensor getting rather different results from the two Suunto devices. There are also enough instances where the fenix and the Ambit3 Peak chest strap track each other nicely and the Spartan Sport WHR Baro (green line) is somewhere else.

Again, sorry, but this is ultimately what science would really be: Statistical work. Not impression-based presentations like here.

Conclusions, Suunto vs. Garmin, to Draw?

What should you think of it, then?

The same as always recommended for heart rate-based training:

If you want to do serious HR-based training, especially intervals, HIIT, training in the cold – take a chest strap for that. Especially if you can also get heart rate variability-based data from the device you use, you will want that. Otherwise, no data would be better than bad data.

If you are just going out for light training, need only a bit of guidance to keep yourself from going too hard on easy runs, then an oHR can still do that. And the convenience of it will give you some data that you wouldn’t otherwise have. In that case, if you don’t build your whole training program around HR data you want to get analyzed, average data can be better for you than no data.

And the perennial question of whether Suunto or Garmin provides the better results?

I’ll see if I have or can get some more data around oHR; I’ll also see about comparing two chest straps, to make sure – but I wouldn’t found my decision on claims around data accuracy, anyways, certainly not when it comes to heart rate, especially from an oHR sensor…

 

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