Many people in the U.S. use home blood pressure monitors to keep track of their health. However, a recent study reveals that millions of adults might be getting inaccurate readings.1
Understanding how cuff size impacts measurements helps ensure accurate blood pressure readings and proper health management.
Blood Pressure Monitors May Not Fit Many Adults Properly
According to early research shared at the American Heart Association’s Hypertension Scientific Sessions 2024, at-home blood pressure kits might not fit many adults in the U.S. properly. (ref)
The research, also published in the journal Hypertension, indicates that many home blood pressure monitors have cuffs that are either too small or too large for about 18 million adults—almost 7% of the population. This improper fit can lead to inaccurate blood pressure readings.
Details on Blood Pressure Monitor Cuff Sizes
In this study, researchers looked at 10 popular blood pressure monitors sold online. Nine out of these 10 monitors had cuffs that fit arm sizes ranging from 8.7 to 16.5 inches in circumference. The researchers focused on these standard-sized cuffs because they are most commonly used by consumers, even though some manufacturers offer additional cuff sizes for an extra cost.
According to the researchers, they found that about 6.7% of U.S. adults (17.3 million people) could not use these devices because their arm sizes were either smaller than 8.7 inches (22 centimeters) or larger than 16.5 inches (42 centimeters). The problem was most prevalent among Black adults (11.8%), compared to white adults (6.6%), Hispanic adults (5.2%), and Asian adults (1.8%).
These figures were derived from comparing cuff sizes with data from the U.S. National Health and Nutrition Examination Survey (NHANES) and U.S. Census data.
Impact of Cuff Size on Blood Pressure Measurement Accuracy
Another clinical trial published in JAMA Internal Medicine examines how the size of a blood pressure cuff affects the accuracy of blood pressure measurements. The study reveals that using a cuff that is either too small or too large relative to the patient’s arm size can lead to inaccurate readings.
Specifically, smaller cuffs tend to overestimate systolic blood pressure, while larger cuffs can underestimate it. The research noted that a well-fitting cuff—covering 80-100% of the arm circumference—is best for obtaining reliable readings.
The findings suggest that healthcare providers need to be mindful of cuff size to avoid misdiagnosis of hypertension or incorrect treatment decisions, particularly for patients with larger or smaller arm circumferences.
The trial employed a randomized crossover design, where participants were tested with various cuff sizes in a controlled setting, ensuring that the results are robust and generalizable. (ref)
High Blood Pressure & Monitoring Recommendations
According to the American Heart Association’s 2024 update, almost half of U.S. adults have high blood pressure. (ref) If not controlled, high blood pressure can lead to serious health problems like heart attack, stroke, and heart failure.
The 2017 guidelines from the American College of Cardiology and the American Heart Association define high blood pressure as having top or bottom readings of 130/80 mm Hg or higher.
They recommend that people with high blood pressure check their levels at home with a home blood pressure monitor between doctor visits. (ref) This helps doctors see if treatments are working.
A 2020 joint report from the American Heart Association and the American Medical Association advises using upper arm cuff devices rather than wrist devices for more accurate readings. (ref)
As research proves, this problem affects a large number of people and can lead to misunderstandings about their health. To avoid these issues, it’s important to use a blood pressure cuff that fits well and to regularly check with a healthcare provider.
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Nancy Maffia
Nancy received a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.
