Apple Has Best Optical HR – err…… no it hasn't

TomTom Runner 3 Spark
TomTom – pretty accurate in my experience (my photo)

A bizarrely scientific, yet incomplete, study by the Heart and Vascular Institute, Cleveland Clinic published through the American Medical Association  purports to show that the Apple Watch has the best accuracy of wrist-based optical HR. Or at least that is how it is being headlined by various tech publications on the internet. This is the first page:

Excerpt, to source.



Based on the comparators, that claim looks like complete nonsense to me. Perhaps I don’t know enough about optical HR?.

Scosche Rhythm+ HR Arm Band Strap
Scosche Rhythm+ – Pretty Accurate In My Experience (my photo)

I don’t claim to be a scientist, engineer or expert in this area but this report has a whiff of incomplete pseudo-science about it. Unfortunately the report’s ‘findings’ are being distributed in super-reputable sources like TIME magazine. do point out a shortcoming, by the study not including TomTom.


Garmin 735XT Optical ELEVATE
Garmin Elevate – Pretty Accurate In My Experience (my photo)

The study authors compare the 2016 Apple Watch 2 to an: aging MIO Fuse (same as MIO Link); a Basis Peak that is now withdrawn from the market; and a Fitbit Charge HR. the latter being from FITBIT Inc ie the company being sued for allegedly having an inaccurate optical HRM.

That’s an unrepresentative sample  of optical HR technology if ever I saw one.

Well, to be fair, it is representative of something. Just *NOT* representative of the quality of optical HR units on offer in the ‘mass’ market.

I wonder if the authors heard of Garmin’s ELEVATE technology? Probably not as Garmin are a relatively niche company that no-one has heard of.

Perhaps they could have looked at Polar’s brand new 6-LED optical array in their M600? They obviously have heard of Polar as they use a Polar H7 chest strap as part of the ‘control’. Maybe the study took place some months ago, before the M600. Fair enough.

Perhaps they’ve never heard of TomTom either? No doubt the American authors don’t have any kind of Satnav in their car (Garmin vs TomTom) so they clearly wouldn’t have heard of TomTom either; Americans are renowned for NOT owning cars.

They probably had heard that Fitbit’s optical HR product is alleged to be ‘bad’ (it’s not, IMHO) because of a recent lawsuit in the US (still not resolved). I can’t think why they might have chosen this product to compare to. Can you?

I could quite accept that they had not heard that Epson do a fairly good wrist-based optical HR unit – although they would no doubt have used an Epson printer or two in their time. Similarly they may well not have heard of Samsung or Sony or Valencell. I’d let them off not knowing about Valencell and the fact that Valencell’s super accurate optical unit is in the Scosche RHYTHM+ – as well as their technology being in the Suunto SPARTAN later this year, although possibly a different physical Valencell sensor. Oh, and before you point out that the most accurate device, the Scosche, is worn on the forearm I can tell you it can also be worn on the wrist and is still pretty accurate in that or any other reasonable bodily location.

FWIW: If you search for “optical wrist hr” then the first page of my Google show references to: Valencell, Suunto and Garmin. Perhaps the authors had not heard of Google’s mystical powers either?

So here are some more points:

1. I have NOT tested the apple Watch 2’s optical HR accuracy. It could be absolutely perfect for all I know (it’s not). Below is an early test from the V1 device from dcrainmaker in 2015. AFAIK the optical hardware in the v2 product is the same as in the v1, although to be fair performance since then could be improved by tweaking algorithms in v2. Draw your own conclusions from the graphs. Dcrainmaker tests, show results as bad as the one shown immediately below and, in balance, also some with ‘fairly good’ to ‘good’ results

Image Source x5:

2. To be fair there are plenty of not so good optical HR units out there. I’m surprised that the authors did not cast their net wider to include those; as that could have shown the Apple Watch 2 was even more market leading than they found (in their small sample of the market)

3. I am not sure which individual or company funded the study. Perhaps that can be clarified? As I have no idea. Or maybe it was being undertaken for the good of medical science? I’d love to know, I really would.

Gillinov declared no conflicts of interest according to Forbes.



Reader-Powered Content

This content is not sponsored. It’s mostly me behind the labour of love which is this site and I appreciate everyone who follows, subscribes or Buys Me A Coffee ❤️ Alternatively please buy the reviewed product from my partners. Thank you! FTC: Affiliate Disclosure: Links pay commission. As an Amazon Associate, I earn from qualifying purchases.

6 thoughts on “Apple Has Best Optical HR – err…… no it hasn't

  1. Going from a charge HR to a Garmin vivoactive HR – the Garmin system is much more accurate than fitbits, bar anything that involves using your arms (rowing, weights) its spot on with my chest belt readings when I compared them

    1. yes fair point. The incorrect point being drawn from the study by the media is that the Apple watch wins on wrist based HR accuracy without saying the sample size is flawed.

  2. Study was done with young, healthy adults who were walking on a treadmill going from 2mph to 6mph.

    That’s (almost) like a walk in the park

    In my own experience, at moderate levels, the Apple Watch (and other optical heart rate monitors) are actually accurate enough.

    It’s where exercise becomes strenuous, or when I do interval training or the workouts involve rapid movement of the wrist and arm that Apple Watch becomes completely unreliable. For example showing 215bpm (which is at least 35bpm off for me) or going from 150bpm to 215bpm then 70bpm in a few seconds.

    Maybe what the study wanted to say that the Apple Watch is accurate enough for the soccer mum or the Apple geek who think exercise is 10,000/day or walking the stairs instead of taking the elevator. Not for runners or serious athletes.

    1. I’m sure the study did have a point. Not sure quite what the point was. Regardless of the real point some media seem to be keen to report the ‘winning accuracy’ of the Apple’s wrist-based optical HR – that is wrong.

  3. I agree, and I’d like to see a REAL comparison between the Apple Watch 2 and the best wrist-based HR monitors, such as Garmins and the Scosche.

Comments are closed.