How to develop a highly accurate optical heart rate monitor

Last Updated on December 28, 2022 by pg@petergamma.org

When the Polar OH1 came out, we were very happy about a PLOS ONE paper, which found out, that the Polar OH1 can be used instead of an ECG device, as far as accuracy is concerned:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217288

We expected a further development as far as the accuracy is concerned in the Polar OH1 successor Verity Sense. But this was not the case, which can be seen in the data of Rob ter Horst as well in one paper about the Verity Sense.

Instead of that, the running time was prolonged. Other optical heart rate watches like the Apple watches increased the accuracy, but not the Verity Sense.

Polar also increased the running of the Verity Sense by a firmware update. We do not know the details of this update.

One exceptional development appeared in the recent years, and that is HeartPy:

https://scholar.google.com/citations?user=OOhuA6gAAAAJ&hl=de&oi=sra

If Polar is not interested in having the most accurate heart rate sensor, and if Apple manages to beat the accuracy of the non-wrist based Polar and Verity Sense sensors by a wrist based watch, what sense does it make to further validate the Polar sports sensors with expensive research grade ECG devices?

We think it is worth to do some experiments:

The Polar OH1 was one of the most accurate optical heart rate sensors. It was non-wrist based, it has 6 green lights, watches usually have 3 green lights. Our experiments is the following:

Use multiple DF Robot optical heart rate sensors:

https://www.dfrobot.com/product-1540.html?gclid=CjwKCAiAhqCdBhB0EiwAH8M_Gv-5QsCRh1w4tghCAkDH3OoBw0gj0J0i8n0sPQc5vcgE-PBOq6hT8BoC23sQAvD_BwE

Test if this increases the accuracy. Use HeartPy to further increase the accuracy. As a reference device, we can use a 3 lead OpenBCI ECG device. If our tests are positive, we can associate with a research institute which has a high quality ECG device and write validation papers about the 3 lead OpenBCI ECG device as well as the DF Robot optical heart rate sensor.