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How do cellphones calculate heart rate ? I understand that the cameras there try to count undulation in blood flow, but is the method of calculation same as that of professional SpO2 monitors ?

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I'm not sure this question is on topic here - it's about technology and apps. But assuming you mean how do apps like this one calculate HR. I believe it measures fluctuations in the colour of the skin (it will change as the quantity of blood varies in the capillaries with pulsing action) and it is simply a case of X beats in 10 seconds = 6*X bpm. SpO2 is a measure of oxygen saturation, not heart rate. – rg255 Mar 20 '14 at 8:13
@GriffinEvo Thus us exactly how it is done. The "redness" of the skin changes with the heart rate and this is measured. See this reference. I would suggest you make it a real answer. – Chris Mar 20 '14 at 9:10
@GriffinEvo I was not sure where the question belonged, this looked the most relevant forum. – Bleamer Mar 20 '14 at 11:01
I asked a related question on Skeptics recently and was pointed to this work - it appears to be detecting changes in skin colour related to heart rate. – Rory M Mar 20 '14 at 11:37
Wouldn't this work out only for people with a very fair complexion ?? – WYSIWYG Mar 21 '14 at 5:17

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