The wrong arm position might affect your blood pressure measurement

Is your blood pressure being measured correctly? It's supposed to be measured while you're seated in a chair, feet on the floor, with your arm supported so your elbow is at heart level. That's the position used in studies of the effects of blood pressure on various aspects of health. However, a busy doctor or nurse might not use the proper position. A small randomized trial published online Oct. 7, 2024, by JAMA Internal Medicine found that the wrong arm position leads to inaccurate measurements. Researchers assigned 133 people (average age 57) to have their blood pressure measured three ways, with a different arm position each time (in random order): correctly, with the arm supported at heart level on a desk; with the hand resting on the lap; and with the arm and hand at the side. These sets of measurements were taken three times. Participants also underwent additional measurements with the arm in the correct position. Scientists found that incorrect positions resulted in significantly higher blood pressure readings, particularly on the top number (systolic blood pressure), than measurements taken in the correct position. It's a good reminder to check the position of your arm any time your blood pressure is measured — by you or anyone else.

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