When you last had your blood pressure taken, you might not have given much thought to how you were positioned, but small mistakes can lead to inaccurate readings. Research highlights various reasons for this, such as using the wrong cuff size or patients sitting improperly—legs crossed or feet dangling. Even stress from being in a clinic, known as "white coat hypertension," can elevate readings. Now, add to that another common issue: incorrect arm positioning.

A Johns Hopkins study found that holding your arm incorrectly during a blood pressure check can significantly inflate the numbers, potentially leading to a misdiagnosis of hypertension and unnecessary medication. The study involved over 130 adults and showed that when arms were not properly supported—either resting on laps or hanging by the side—blood pressure readings were often overestimated. For instance, when the arm was on the lap, both systolic and diastolic pressures increased by around 4 mmHg. The problem worsened when the arm was by the side, with systolic pressure rising by 6.5 mmHg and diastolic by 4.4 mmHg.

These inaccuracies might not seem dramatic, but for someone with a systolic pressure of 128 mmHg (just below the hypertensive threshold of 130 mmHg), improper arm positioning could push them into the hypertensive range, leading to unnecessary treatments. Dr. Tammy Brady, the study's senior author, emphasizes that blood pressure readings should not be taken lightly, as decisions about a patient's health often rely on these numbers.

There are established guidelines for accurately measuring blood pressure, including ensuring the patient waits five minutes, keeps their feet flat, has a supported back, and that the room is quiet. However, the rush of daily clinical practice and exam room layouts often make it hard to follow these steps perfectly. As Dr. Stephen Juraschek of Beth Israel Deaconess Medical Center points out, these errors tend to cluster, leading to more severe inaccuracies.

Full article by NPR can be read here.