Improper arm positioning can skew blood pressure readings

A study conducted by researchers from Johns Hopkins Medicine, published in JAMA Internal Medicine, reveals that improper arm positioning during blood pressure measurement can lead to significantly inaccurate readings. The study, which involved 133 participants aged 18 to 80, found that leaving the arm unsupported by the side of the body can increase systolic blood pressure readings by approximately 6.5 mmHg and diastolic readings by 4.4 mmHg.

Inaccurate readings can stem from muscle contraction used to hold the arm or the effects of gravity when the arm is placed below heart level, such as on the thigh. To ensure accuracy, medical guidelines, including those from the American Heart Association, recommend sitting quietly for at least five minutes before measurement, supporting the back, keeping feet flat on the floor without crossing legs, and resting the arm on a stable surface at heart level.