Commonly used arm positions can overestimate blood pressure readings: study

There's definitely a huge variance in blood pressure readings depending on posture, relaxation, arm position, recent activity, etc. If you buy a blood pressure monitor, it's really interesting to see how "random" a single reading at the doctors' is, and how large your fluctuation throughout the day is.

That being said, it really makes me wonder about studies that correlate blood pressure with other things. Is the blood pressure really being measured "correctly" in all those studies? Or not?

In other words, if your "true correct" blood pressure is lower than what the doctor normally takes, but then a lot of the studies are based on real-life "incorrect" higher blood pressures, then don't you similarly want an "incorrect" higher reading for consistency? Or are the studies always really done with far more accurate blood pressure readings, where the patient sits still for 5 min beforehand, keeps their legs uncrossed, is totally free of stress and anxiety, didn't exercise beforehand, etc.?

Also doctors and nurses are known to do an abject awful job of measuring bp according to the defined procedure. It’s usually way off when taken clinically.

Ars article here but there’s plenty in pubmed too.

https://arstechnica.com/health/2024/10/your-doctors-office-c...

[edit] The prep guidance is…

> You must not eat, drink, exercise, or smoke within 30 minutes of a reading. You must have an empty bladder. You must sit straight up in a chair with back support. Your legs must be uncrossed and your feet must be flat on the ground. The arm to be measured must be rested on a flat surface so that it is at the same level as your heart, not lower, not higher. You must sit calmly, without talking for five minutes to relax before the reading. When it's time, an appropriately sized cuff should be wrapped around your bare upper arm, right above the elbow; it should never be wrapped over clothing. At least two readings should be taken, with the average recorded. Ideally, readings should be taken in both arms, with the highest readings recorded.

When was the last time you got it measured properly? Literally never for me in a clinical setting. I don’t know why they bother honestly.

Doctors recognize that non-invasive BP measurement is an imperfect screening tool. Anybody worth their salt isn't getting worked up about these level of details, because it's largely a waste of time and effort. The solution to an error prone screening tool is not to repeatedly use the screening tool. You move on to more accurate and focused methods of testing.