Arm or wrist blood pressure cuffs – which one is more accurate?

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Many people with high blood pressure may have been advised to measure their blood pressure with a home monitor.  Being able to monitor blood pressure at home has numerous advantages for several reasons:

· It can give a picture of what blood pressure is doing as a person goes about their daily life

· It helps a person to see how their blood pressure compares when taken at home compared to when taken at a doctor’s office

· It can help a person to see how well their medications and lifestyle changes are working for them

· It can give a person a feeling of a sense of more control of their condition

· It gives a person’s doctor a more complete picture of what blood pressure is like from day to day

These advantages are all worthy of investing in a home blood pressure monitoring kit but the real question is which type to use – one that uses a cuff measuring around the upper arm or around the wrist?

Choosing the best cuff to use

Some people prefer using a wrist cuff as it is often easier to access than the upper arm and does not require a person to roll up their sleeves or remove their shirt to gain access to that site.  Another advantage of a wrist cuff is for individuals who are obese and may not be able to use a cuff that fits properly around their upper arm.  Also anyone with an injury of the upper arm would benefit from using a wrist cuff.

However, the American Heart Association does not recommend a wrist cuff for the vast majority of people for several reasons.  There was a study published in 2016 in the journal Hypertension, were researchers’ trained 721 people to use a wrist cuff to measure their blood pressure at home in addition to being trained on how to use a traditional blood pressure cuff that wraps around the upper arm.  Each participant’s blood pressure was measured at a doctor’s office using both devices as a reference.

When the wrist devices were used at home, readings when compared to using an arm device were noticeably different.  Up to 86 percent of participants had systolic (top number) and diastolic (bottom number) readings that were off by at least 5 mmHg compared with their arm measurement.  Also three-quarters of the participants had readings at least 10 mmHg higher compared with the arm reading. 

One of the reasons why readings when using a wrist cuff were apparently artificially higher was due to participants positioning the cuffs on their wrist incorrectly.  When taking a blood pressure reading using the wrist, the arm must be positioned correctly during testing.  If the wrist reading is taken while the wrist is resting in a person’s lap, then the reading will be inaccurate.  When taking blood pressure, it needs to be at heart level, like the upper arm is.  Since the wrist is farther from the heart, this can lead to inaccuracies in blood pressure measurement. 

In another small study in 2013 in Blood Pressure Monitor, wrist and arm devices (one worn on each arm) were used to automatically measure participants’ blood pressure over a 24-hour period.  Both the systolic and diastolic measurements from the wrist monitor were significantly off at certain times compared with the arm monitor. 

Other factors to consider are that the arteries in the wrist are deeper than those in the upper arms, which means they are harder for the monitor to detect.  They are also thinner, resulting in a weaker signal. 

In conclusion

There are many factors to consider in deciding whether to use an arm or wrist cuff in monitoring blood pressure at home.  It appears from studies analyzing this concern to the recommendation from the American Heart Association the best one to use is an arm cuff.  Since the goal in measuring blood pressure at home is to get the most accurate readings possible, a blood pressure monitor using an arm cuff seems to be the most logical solution.