About 7% of American adults—about 17 million people—don’t fit properly in the blood pressure cuffs that come standard with most at-home blood pressure devices, according to a new study.
This figure is concerning, researchers argued, as ill-fitting blood pressure cuffs can lead to inaccurate readings.
The research, published in Hypertension on September 5, assessed 10 popular blood-pressure monitoring devices. Nine of the devices offered blood pressure cuffs that ranged in size from 8.7 inches to 16.5 inches. However, millions of people have an arm circumference that falls outside this range.
Specifically, 6.4% of adults have an arm circumference that’s above 16.5 inches—of this group, about two-thirds have high blood pressure and, as such, should be monitoring their blood pressure at home.
“Knowing that 16.5 million U.S. adults will be under-cuffed—and thus obtain blood pressure measurements that are overestimated—if they use one of these popular devices raises concern,” study author Tammy Brady, MD, PhD, associate professor of pediatrics at the Johns Hopkins University School of Medicine, told Health.
The study calls into question the accuracy of at-home blood pressure tests that patients report to their doctors. This is a “significant issue” since these results are often used to make important clinical decisions, she explained.
The problem is even more troubling for Black Americans, as nearly 12% don’t fit this standard blood pressure cuff sizing. The data showed that 6.6% of white adults, 5.2% of Hispanic adults, and 1.8% of Asian adults have the same issue.
Here’s what experts had to say about the importance of choosing a blood pressure cuff that fits, plus other tips to ensure your at-home blood pressure readings are accurate.
Last year, Brady and her colleagues authored a study that investigated how using an ill-fitting cuff affected a person’s blood pressure results. All participants used a “regular” size blood pressure cuff, regardless of their arm size. The researchers found that those who should’ve used a “small” cuff had lower blood pressure readings, while people who should’ve used a “large” or “extra-large” cuff had higher readings. Being just one size off can affect a person’s blood pressure reading, the authors said.
To build on these findings, Brady and her team wanted to investigate how often these issues might be coming up for people testing their blood pressure at home. They found that “the cuff sizes typically provided with devices purchased from an easily accessible marketplace don’t fit a large proportion of the U.S. population,” she explained.
There are approximately 122 million American adults living with high blood pressure, and over half likely require a large or extra-large blood pressure cuff, a 2022 study found.
In addition to the fact that Black Americans may be more likely to have issues finding a blood pressure cuff that fits properly, Brady said people with obesity may also be at a higher risk of having this issue.
“Individuals with obesity are most likely to use a cuff that doesn’t fit well—they are most likely to have a larger mid-arm circumference and therefore more likely to not easily find a device ‘off the shelf’ with a cuff that fits their arm,” she said.
Most at-home blood pressure cuffs for adults come in small, regular, large, and extra-large sizes. Some manufacturers do offer non-standard cuff sizes for an additional fee. However, people are more likely to just make do with the cuff that comes with the device, not knowing that they could be at risk of an inaccurate reading, Brady said.
Luckily, issues with blood pressure cuff sizing are largely restricted to at-home devices—readings at your doctor’s office should be accurate.
“Most physicians’ offices are very careful to choose the right cuff size, and all of the staff are typically trained well in this aspect,” Stephen Chan, MD, PhD, director of the Vascular Medicine Institute and the Center for Pulmonary Vascular Biology and Medicine at the University of Pittsburgh Medical Center, told Health.
Because uncontrolled hypertension can lead to heart attack, heart failure, stroke, and other complications, it’s important that people with the condition keep a close eye on their blood pressure readings.
“Everyone with hypertension [should] check home blood pressure periodically,” Luke Laffin, MD, co-director of the Center for Blood Pressure Disorders at Cleveland Clinic, told Health.
The American Heart Association (AHA) recommends using an automatic, cuff-style monitor that goes on your upper arm. Avoid wrist or finger monitors, which can be inaccurate.
Before you order an at-home blood pressure device, measure your arm. You can use a soft or paper measuring tape to determine the circumference of your arm at the midpoint between your elbow and shoulder.
In terms of cuff length, the inflatable part of the blood pressure cuff should cover about 75% to 100% of the distance around your upper arm. The cuff should be wide enough to cover from 40% to 80% of the distance from your elbow to your shoulder, said Chan.
It’s also important that the cuff you use is associated with the specific blood pressure monitor you choose—if you use an “off-brand” cuff, you can’t be assured that it will give you an accurate reading, Brady said.
You can order an at-home blood pressure monitor once you know which size you need. For more guidance, the American Medical Association hosts a website that lists blood pressure monitors that it has validated for accuracy.
Once you’ve ordered an at-home blood pressure monitor, bring it to your next appointment with your healthcare provider so they can ensure you’re using it correctly.
The AHA also offers tips on how to receive the most accurate reading possible:
- Use the bathroom before you take your blood pressure.
- Don’t smoke, drink caffeinated beverages, or exercise within 30 minutes of taking your blood pressure.
- When sitting up, don’t cross your legs, and sit with your back straight and supported.
- Remove clothing on your arm so the cuff is directly on your skin.
- Measure blood pressure at the same time each day or however often your healthcare provider recommends.
- Take a few measurements and write down the results. (Some monitors can keep track of your numbers for you.)
