Getting your blood pressure checked is a routine part of medical visits, but a new study reveals that the way your arm is positioned during measurement could significantly affect the results – potentially leading millions of people to be wrongly diagnosed with high blood pressure.
Researchers at Johns Hopkins University found that when blood pressure is measured with the arm resting on a patient’s lap or hanging by their side – positions commonly used in doctor’s offices – the readings can be artificially inflated by 4-10 points compared to the recommended position with the arm supported at heart level.
“These findings are eye-opening because they show how a simple thing like arm position can lead to meaningful errors in blood pressure measurement,” says Dr. Tammy Brady, the study’s lead author. “We estimate that improper arm positioning could result in up to 40 million Americans being misclassified as having high blood pressure.”
The Proper Way vs. Common Practice
The correct way to measure blood pressure involves:
- Having your arm supported on a desk or table
- The middle of the blood pressure cuff should be at the heart level
- Being seated with back supported and feet flat on the floor
However, in many medical settings, blood pressure is often taken:
- With the patient’s arm resting on their lap
- With the arm hanging down at their side
- While seated on an exam table without proper arm support
The study found that these incorrect positions can add:
- About 4 points when the arm rests in the lap
- About 7 points when the arm hangs at the side
- Even higher readings in people who already have high blood pressure
Why It Matters
These extra points aren’t just numbers – they can make the difference between being diagnosed with high blood pressure or not. This could lead to unnecessary medication, additional medical visits, and unwarranted anxiety about health.
The problem may be even more significant for certain groups. The study found that people with existing high blood pressure showed even larger measurement errors, with readings off by up to 9 points when their arm wasn’t properly positioned.
What You Can Do
Dr. Brady suggests these steps for more accurate readings:
- Ask for your blood pressure to be taken with your arm supported on a desk or table
- Ensure the cuff is at heart level
- If proper support isn’t available, request that the healthcare provider note how your arm was positioned
- When taking blood pressure at home, follow the same positioning guidelines
The researchers emphasize that this isn’t just about following rules – it’s about getting accurate information to make proper healthcare decisions. With high blood pressure being a leading cause of heart disease worldwide, accurate measurement is crucial for proper diagnosis and treatment.
“The good news is that this is a fixable problem,” says Dr. Brady. “By raising awareness about proper positioning and making simple adjustments in how we measure blood pressure, we can improve the accuracy of these important readings.”
The study, which included 133 participants and was published in JAMA Internal Medicine, underscores the importance of standardizing blood pressure measurement techniques in healthcare settings to ensure accurate diagnosis and appropriate treatment of high blood pressure.
