A recent medical study has raised concerns that some individuals might have been wrongly diagnosed with high blood pressure. Researchers have warned that different arm positions during testing can significantly affect the results. According to NHS guidelines, the correct posture for taking a blood pressure reading includes sitting down with your back supported and legs uncrossed for at least five minutes prior to the test. Additionally, it’s advised to “sit on an upright chair with a back, place your feet flat on the floor, rest your arm on a table and relax your hand and arm, wear something with short sleeves so the cuff does not go over clothes, relax, breathe normally and do not talk during the test, and take another reading a few minutes after your first reading to check it’s accurate”.
In a new study, researchers at Johns Hopkins Medicine in the US looked at blood pressure readings with arms in different positions. The findings, published in the medical journal JAMA Internal Medicine, found arm position makes a “huge difference” when it comes to an accurate blood pressure measurement. Dr Tammy Brady of the Johns Hopkins University School of Medicine said: “Few studies have rigorously evaluated the effects of arm position on blood pressure. This crossover randomised clinical trial demonstrates the considerable effect of arm position on blood pressure readings.” Specifically when measurements are obtained with arm positions frequently used in clinical practice – ie on the lap or at the side – the readings obtained are markedly higher than those obtained with the arm positioned according to published guidelines.
The NHS advises that normal blood pressure is between 90/60mmHg and 120/80mmHg. High blood pressure is considered to be 135/85 or higher if the reading was taken at home, or 140/90mmHg or higher if the reading was taken at a pharmacy, GP surgery, or clinic. The study found that putting an arm on the lap overestimated systolic pressure (the top number in a blood pressure reading) by 3.9mmHg and diastolic blood pressure, the bottom number, by 4mmHg. An unsupported arm hanging at the side meanwhile overestimated systolic pressure by 6.5mmHg and diastolic by 4.4 mmHg.
This study sheds light on the importance of adhering to proper testing protocols to ensure accurate blood pressure readings and correct diagnosis. Individuals are urged to follow the recommended guidelines for blood pressure measurement to avoid potential misdiagnoses and ensure appropriate management of their health. It is crucial for healthcare professionals to be aware of these findings and implement the necessary precautions during blood pressure assessments to provide patients with reliable and accurate results.