Reminds me of how I found out I had a weird blood pressure oddity.
I was having a routine checkup as part of a voluntary "collect some data" thing. The medic attached a cuff to my arm attached to a fancy automatic tester thingy. "Just stand there while it takes your pressure".
Ok. Closes eyes and relaxes. Oooo, that feels oooodddddddd.....
CRASH! Wake up on floor surrounded by fragments of fancy tester thing that I'd yanked off the table as I passed out.
A few years later as a pre-op checkup, I mentioned this to my doctor as he prepared to take my blood pressure with, yes, another automatic thingy. "I think I'll pass out if I'm not sat down". No, it'll be fine.
CRASH!
It's now highlighted in my medical notes: patient must be seated when BP taken. I've no idea why they previously asked me to stand as my home test kit specifies sitting, and whenever I've seen BP taken in films and wotnot with the old stirrup pump and valve kit, the patient is always seated.
.