Assuming that Polar used novel algorithms to reduce noise in noisy PPG signals in their firmware update of the Verity Sense, they would have achieved a higher accuracy of the sensor.

Is it not suprising, that wrist based watches like the Apple watch are more accurate than the Polar OH1 or the Verity Sense, which can be strapped onto your upper arm?

Which sense does this external sensor make, if it is no longer more accurate than for instance an Apple watch, what was been demonstrated in Rob ter Horst tests?

Does Apple already use these new algorithms in their watches to reduce noise in PPG signals, which makes those more accurate than a Polar OH1 and a Polar Verity Sense?

And assuming that Polar used these new algorithms in the firmware update, which they did not use before, they would have achieved a higher accuracy, which has not been demonstrated somewhere. But the result of the fimware update was a longer battery life.

Was this achieved by an internal reduction of the sampling rate? Was it the goal of Polar, to get a sensor with longer battery life, but not to achieve a sensor with greater accuracy?

The Polar OH1 is a very well validated sports sensor, also scientifically, which the Verity Sense is not yet. It is a suprise that the Polar OH1 and the Verity Sense do no longer belong to the most accurate optical heart rate monitors, according to Rob ter Horst tests, and also and disappointing.

If a company like Apple is capable of developing a wrist based optical heart rate monitor which as been demonstrated in Rob ter Horst and Milind Y. Desai studies, which is the closest to an ECG or a Polar H10 ECG chest strap, why is Polar not capable of developing a sensor with an accuracy which is comparable to the accuracy of a Apple whatch in Rob ter Horst study? Only then the construction with a sensor which can be strapped onto the upper arm makes any sense.

If not, the upper arm sensor construction is superfluous. It is highly desirable that Polar is again developing a sensor that is way ahead in the Rob ter Horst ranking.