Checking Blood Pressure in Both Arms

Most of us have had our blood pressure taken, generally in the left arm if you are right-handed.

But should blood pressure potentially be taken in both arms? For patients with hypertension or risk factors for cardiovascular disease such as diabetes, the answer is yes.

Cardiovascular experts have long known that a significant difference in blood pressure between the two arms can indicate potential problems such as atherosclerosis—plaque buildup in the arteries. Too much plaque on artery walls can block blood flow to critical organs such as the heart or the brain and result in heart attack and stroke. Catching it early saves lives.

A new study published in the journal Hypertension confirms the importance of measuring blood pressure in both arms. Led by researchers in the UK, the study merged data from 24 other studies and looked at 54,000 adult patients around the world.

The research is the first to show strong evidence that the greater the difference in blood pressure between arms, the higher the additional risk for developing heart disease. For each extra point of difference, researchers reported a one percent increase in the 10-year risk of a new episode of angina, heart attack, or stroke.

What Is Systolic Pressure?

The heart is a pump that works in tandem with the lungs. The right side of the heart sends oxygen-deficient red blood cells to the lungs for gas exchange and the left side of the heart receives back oxygen-rich blood to pump to the rest of the body.

During the pumping phase, pressure in the blood vessels naturally rises. We measure that as systolic pressure—the top number of your resting blood pressure. Normal systolic blood pressure should be around 120.

The UK study identifies 10 points as the critical threshold of difference between the arms. That’s lower than the previous guideline of 15. For example, systolic blood pressure of 118 in one arm and 120 in the other causes little concern. But a reading of 120 in one arm and 131 in the other does. Recognizing this often-overlooked difference and delving further into a personal history and physical exam, together with additional targeted testing, may prevent a catastrophic cardiovascular event down the line.

Blood Pressure Can Fluctuate

In everyday life, of course, the average person’s blood pressure is variable. It changes frequently, around the clock. It rises with exercise or any other physical activity or with emotional excitement and drops during sleep and during times of relaxation.

Doctors focus most often on resting blood pressure for diagnosing and treating hypertension. It is immensely important to get several blood pressure readings, both at your doctor’s office and outside, for accurate diagnosis and appropriate management of hypertension.

In recent years, durable, inexpensive, accurate, portable blood pressure monitors have become readily available to patients. This has helped both patients and doctors to improve blood pressure management. With a portable monitor, my patients are able to monitor their blood pressure at home—under consistent circumstances and over a longer time period—giving me a solid snapshot of their condition on an ongoing basis.

Playing an Active Role

Hypertension is often known as a “silent killer” because a patient can have mild or no symptoms for several years, in spite of ongoing damaging effects of high blood pressure on their critical organs, such as the heart, brain, or kidneys. Because they “feel fine,” some people may resist taking the steps needed to correct their high blood pressure—typically a combination of weight management, reducing sodium in the diet, and medication.

Education is a key part of treatment planning and execution, and fortunately, my patients tend to be very responsive once we emphasize the serious potential for heart attack, stroke, kidney failure, and peripheral vascular disease, vision loss, bowel disease, limb loss, and other problems.

At-home blood pressure gauges can store results, empowering our patients to provide us with high-quality and detailed information that is valuable in helping us tailor a specific treatment plan for them.

My patients also bring their portable units to their office visit, where we can also check its readings for accuracy by comparing them to those of our medical-grade, calibrated office equipment. Access to the portable machine’s recorded results is useful during telehealth visits as well.

An Accurate Assessment

To ensure accuracy when taking blood pressure at home, we recommend using a machine designed for use on the upper arm, which generally delivers a more precise result than one that measures at the wrist.

For the best results, follow the American Heart Association’s guidelines for taking your blood pressure at home:

• Take your blood pressure at the same time each day.
• Don’t exercise, smoke, or drink caffeinated beverages for at least 30 minutes before screening.
• Sit upright with feet flat on the floor for five minutes.
• Place the cuff on bare skin.
• Position the cuff according to your machine’s instructions.
• The first few times that you measure, measure both arms two minutes apart. After that, use the arm with the higher reading, unless your doctor instructs you otherwise.
• Take two readings, two minutes apart. Record the readings if your machine doesn’t do it automatically. This also gives you a permanent record for yourself, should the machine malfunction at some point.

When to Check Both Arms

The practice of taking blood pressure in both arms is not yet a mainstream activity with all patients. But, as mentioned, it is best practice for those with hypertension and other risk factors for heart disease, from age, sex, or family history to the presence of underlying conditions like diabetes.

As we learned from the UK study, a difference between the arms of 10 points or more is reason for the physician to dig more deeply into the patient’s condition. For example, it may indicate a narrowing in the artery that feeds the arm from the shoulder. Atherosclerosis, or plaque, is a systemic process, and narrowing in an arm artery could be an early warning of narrowing in other critical areas. A narrowing in the coronary arteries that supply blood to the heart could cause a heart attack; in the arteries of the neck, it might lead to stroke.

Everyone’s metabolism, risk, and genetic makeup are different, and your doctor is the best source of sound advice. If you have risk factors for heart disease and routinely monitor your blood pressure, it’s best to have a conversation with your doctor about checking both arms. He or she will work with you to determine next steps and any additional testing required, such as a CT scan to detect arterial calcification, a stress test, or an ultrasound of the blood vessels to determine plaque burden.

Communication Is Key

At MedStar Heart & Vascular Institute, we encourage you to be in contact with your physician for a regular physical exam. This is increasingly important as you age: men over 45 and women over 55 in general are at higher risk for heart disease.

If risk factors are identified, our cardiology team works with you to determine the best way to mitigate your risks and will conduct regular monitoring and testing to suit your unique medical profile.

And of course, we want to emphasize the most important point of all: Seek emergency aid immediately if you experience any cardiovascular symptoms—chest pain, tightness, or heaviness; shortness of breath; nausea; dizziness; and pain in the jaw, neck, or left arm.

When the heart muscle is involved, time is of the essence. Our experts in heart and vascular care want to see you today to help you live a long and happy life.