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It's apprently not very accurate but I suppose good enough.

https://www.acc.org/latest-in-cardiology/articles/2017/07/24...

So I can actually feel my pulse in my upper arm presumably when the device is in it's measurement range so I've always presumed that it's sensing that with a pressure transducer and a simpleish algorithm, but I never thought to ask about how it actually works, and now I wonder if other people can feel them working.

Wont the stiffness and amount of tissue around the vessels change that ? And thus won't it be different from person to person not because the blood has a different pressure but because of the way we are measuring it.

It doesn't just stop the pulse from being detected, it stops the blood from passing into the limb where the cuff is applied.

That's going to mostly depend on how much pressure is behind the blood.

I never knew that, thanks. So when the machine ramps up the pressure, then ramps up some more, then some more, you know you're in trouble?

I've always asked myself the question how this works, but actually never looked it up. Thank you for this explanation!

Brilliant and concise, thanks!