Last Updated on February 4, 2023 by pg@petergamma.org
As far as we know, the development of HRM measurement devices started with ECG devices. The people who are the most interested in the most accurate devices are scientists and medical doctors.
The medical doctors increased the accuracy of their devices by creating 3 lead ECG devices which is the gold standard for HR measurements. This means that 3 channels are independently measured, analysed and amplified. These are the most accurate devices.
3 lead ECG devices are not very suitable for sporting activities. Sports sensor manufacturers therefore started to develop chest straps, which are more comfortable. But these devices are not 3 lead ECG devices, for instance the Polar H10 chest strap for 90 USD is a single lead ECG device with one channel.
Rob ter Horst uses two Polar H10 chest straps in his test. But he does not use the average of two Polar H10 chest straps.
Why does Rob ter Horst not do this? Every scientist would do everything to increase the accuracy of his reference device? Is this also a secret plan of Rob to cheat us together with the sports watch sellers?
PPG devices started as single channel devices. Then more channels where added. But only for sports watches. We do not know of similar devices for clinical and non exercise physiological applications.
Scientists and medical doctors created 3 lead ECG devices to reach a maximal accuracy. This is eventually not possible with PPG watches. We can increase the number of channels as much as we want, do noise removal and anything which is possible to increase the accuracy, it is eventually limited and not possible to increase the accuracy further. Or only if we invest a lot of money which makes the devices expensive. If this would be possible, we are convinced that someone would have done it. Ask Peter Charlton or another scientist about the details.