Blood pressure readings can be significantly impacted by a seemingly small change in arm position, according to a recent study conducted by researchers at Johns Hopkins Medicine in the US.
The study examined blood pressure readings taken when the arms were supported on a desk, on a lap, and when hanging at the patient’s side without support. It was discovered that certain arm positions, such as resting the arm on the lap, could lead to a significant overestimation of blood pressure readings.
To ensure accurate blood pressure measurements, the NHS advises individuals to sit upright in a chair with back support, place both feet flat on the floor, and rest the arm on a table or desk. It is also recommended to rest for five minutes before taking a reading and then take another reading a few minutes later to verify its accuracy.
Published in the journal JAMA Internal Medicine, the study revealed that positioning the arm on the lap overestimated systolic pressure by 3.9mmHg and diastolic pressure by 4mmHg. Conversely, an unsupported arm hanging at the side led to an overestimation of systolic pressure by 6.5mmHg and diastolic pressure by 4.4mmHg.
Dr Tammy Brady from the Johns Hopkins University School of Medicine emphasised the importance of arm position for accurate blood pressure measurements, recommending that arms should always be supported on a firm surface like a desk or table.
During the study, 133 adults between the ages of 18 and 80 had their blood pressure taken during a single visit. Prior to the readings, participants emptied their bladders, walked for two minutes to simulate a visit to the clinic, and then rested for five minutes with back and feet support.
Each individual wore an upper arm blood pressure cuff and had multiple measurements taken with a digital blood pressure device. The results indicated that arm position could lead to high blood pressure readings, with the highest readings observed when the arm was hanging by the side.
The NHS considers normal blood pressure to be between 90/60mmHg and 120/80mmHg. High blood pressure is defined as 135/85 or higher when read at home, or 140/90mmHg or higher when read at a pharmacy, GP surgery, or clinic.
This study underscores the importance of proper arm positioning during blood pressure readings to avoid potential misdiagnoses and ensure accurate measurements. It serves as a valuable reminder for healthcare professionals and individuals alike to be mindful of this simple yet crucial factor in assessing blood pressure levels.