When it comes to checking blood pressure, even small mistakes can make a big difference. Many people don’t realize that the way they sit, or even where they place their arm, can lead to a falsely high reading. That’s the takeaway from a recent study referenced by cardiologist Dr. Evan Levine in an Instagram post, which shows how arm position during a blood pressure test can lead to unnecessary concern, and in some cases, overtreatment.
The study: How arm position changes readings
Published in JAMA in October 2024, the study looked at 133 adults with an average age of 57. Each participant’s blood pressure was measured in three different positions:resting their arm on a desk at heart level,resting it in their lap, and
letting it hang loosely by their side.The results were striking. When arms hung by the side, systolic blood pressure (the top number) was an average of 6.5 mmHg higher and diastolic (the bottom number) 4.4 mmHg higher than when the arm rested on a desk. Even placing the arm on the lap showed elevated results, with systolic readings 3.9 mmHg higher and diastolic 4 mmHg higher compared to the desk position.For those already diagnosed with high blood pressure, the difference was even greater. In this group, systolic readings were 8.5 mmHg higher when the arm was hanging by the side instead of resting at chest level. These numbers matter, because such differences could lead to patients being prescribed stronger medications than they actually need.
Dr. Levine’s advice: Don’t let position skew results
Dr. Levine highlighted the findings to raise awareness about proper technique. He explained that the blood pressure cuff should always be placed directly on the skin, not over clothing, and positioned on the forearm at heart level. He also cautioned against placing the arm on the lap or letting it dangle by the side.
Blood pressure is one of the most important indicators of heart health. According to the CDC, consistently high readings can influence treatment decisions, including prescriptions for lifelong medication. A reading that’s just a few points higher than reality could mean someone ends up being treated for high blood pressure unnecessarily, with potential side effects from drugs they may not actually need.
The correct way to measure blood pressure
The CDC recommends several best practices to ensure readings are accurate:Avoid eating, drinking, or smoking 30 minutes before the test.Empty your bladder beforehand.Sit comfortably with your back supported for at least 5 minutes before measuring.Place both feet flat on the ground, legs uncrossed.Rest your arm on a table so the cuff is level with your heart.Ensure the cuff fits snugly but not too tight, and always place it against bare skin.Stay silent during the reading.
