Honestly I'm not sure what a single point-in-time reading even accomplishes. I've been hooked up to a continuous blood pressure monitor a few times and it's always fun to see how low I can get it. It seems pretty useless without seeing where it fluctuates over time not in a doctor's office.
Aktiia makes a continuous optical blood pressure monitor that is available in the EU. It's like wearing a fitbit, but for bp. You calibrate it with a pressure cuff once a month.
I'm pretty sure they're going through fda approval in the USA now.
Once, when hospitalized, I had an arterial BP monitor that was continuous. The last systolic number I remember seeing before passing out from sepsis was in the 70s.
