u/mc0e

I'm currently messing about with my smartwatch, with a view to getting it to provide the sort of alerts and insights that I might get from the visible armband if it was available in my country (Australia).

I'm curious about the technology visible uses. Is it based on an optical sensor like many smart watches have, which you'd see as a flashing light on the inside of the armband (photoplesythmography)? Alternatively, I gather it's made by Polar, which makes me wonder if they're reading electrical nerve signals? That would presumably show up as electrical contact areas on the inside of the armband, which probably just look like rubbery areas on either side of the measuring device?

If anyone is interested, I'm working on a Pebble Time 2, which is an open source smart watch with a battery life measured in weeks (depending what you get it to do that might tax the battery). Once I've made a bit more progress, I'm likely to be back with more questions about what people find useful or would find useful in an app for ME/CFS, POTS and related conditions.

I also have a Polar H10, and may make use of this also, or instead, though it's non-rechargeable batteries make it somewhat less appealing for long term use.

Less obvious things I'm interested in doing with this include making use of the roughly 0.1 Hz swings in heart rate with POTS, and investigating possible hardening of arteries over time with long term high salt diets.