Rob ter Horst tested the accuracy of more than 100 smartwatches scientifically:
But if his tests would be repeated with the protocol the cardiologists of the Cleveland Clinic have used, for instance on a treadmill up to about 15 km/h:
they used a device which is similar to the Schiller CS200 ECG stress treadmill:
We suppose with such as device the result would be completely different. The cardiologists from the Cleveland Clinic in Ohio have basically only written two papers about fitness tracker accuracy :
Then they stopped writing papers about this topic. The protocol of the second paper of the Cleveland Clinic is the most advanced protocol we know to test the accuracy of fitness trackers scientifically at the highest accuracy level possible.
Many years ago, DC Rainmaker introduced optical heart rate monitors with devices such as the Mio Link and the Garmin Forerunner 235. These optical heart rate monitors where handy and good looking. Later on Ray and the5krunner indroduced the Polar OH1 as a very accurate optical heart rate monitor, if not the most accurate. But both of them did not deliver a scientific proof for these statements.
In the two papers of the Cleveland Clinic in Ohio we basically can find everything we need to know about scientific fitness tracker accuracy validation. The Cleveland Clinic delivered scientific data which could be compared from one device to the other with numerical and statistical data. But then they stopped testing. If these fitness trackers would become more and more accurate, as for instance Rob ter Horst claims in his tests, would not reseach insitutes as for instance the Cleveland Clinic continue to validate fitness tracker accuracy. But they don’ t.
This bring us to the hypothesis that these new optical heart rate sensors which where introduced with for instance the Mio Link or the Garmin Forerunner 235 about 10 years ago are suitable for fitness trackers, but they are only of limited use for scientific applications.