How Can Blood Pressure Be Different In Each Arm?

Overview

If you checked your blood pressure in both arms and there is a little difference between arms, this is no cause for worry as blood pressure can vary slightly between arms. However, if the difference in blood pressure is above 10–15mmHg, it is a risk for cardiovascular diseases.  

What does it mean if you have different blood pressure in each arm?

Different blood pressures in each arm means that you consistently have different systolic (the top number) or diastolic (the bottom number) blood pressures in each arm. It’s common for blood pressure to be slightly different in both arms. This has been observed for over a century. Blood pressure being different in both arms is not associated with handedness, age, sex or race. However, a blood pressure difference above 10–15mmHg is associated with an increased risk for cardiovascular diseases.^1,2,3 

It’s not a strange practice for your blood pressure to be measured in both arms at the doctor’s office. The NICE hypertension guideline recommends this. And if the blood pressure difference between arms is consistently above 10–15mmHg, the guideline recommends that all future blood pressure measurements be taken on the arm with the higher blood pressure. Treatments are usually based on the arm with the higher measurement.

Even though this is the recommendation, it is not practiced most of the time. If blood pressure is not measured in both arms, it could make hypertensive people be misdiagnosed as non-hypertensive (if the arm with the lower blood pressure is used for measurement). This could also lead to poor control of hypertension. You can ask our health care provider to check your blood pressure in both arms on your next visit if this hasn’t been done before.^1,3,4 

What causes different blood pressure in each arm?

A blood pressure difference of more than 10–15mmHg is strongly associated with peripheral artery disease and less commonly associated with an aortic dissection.^5,6 However these are not definitive causes as more research needs to be conducted to find the causes.

Causes

Peripheral artery disease also known as peripheral vascular disease is a progressive condition where blood vessels outside the heart taper and get blocked. This impedes the free flow of blood in these vessels.^6,7,8 

The most common cause of peripheral vascular disease is atherosclerosis, which refers to the buildup of fats in the walls of blood vessels. Other causes include infection, injuries, and a structural problem that blocks the free flow of blood.⁸

You could have this disease without any symptoms. But a common symptom is intermittent claudication,which refers to a pain in one or both legs while you walk that goes away when you rest. Other symptoms include weakness and wasting of the legs, weak pulses in the legs, ulcers in the legs, loss of leg hairs, unusual changes to the skin of the leg, and dead tissue on the leg.^7,8,9

Aortic dissection is a rare, life threatening condition. It is diagnosed in 3 to 5 in 1 hundred thousand people. It is caused by the separation of the layers that make up the wall of the aorta—a large artery that carries blood away from the heart. The separation of the layers of the aorta’s wall is caused by a tear of the innermost layer or bleeding within this wall.

The symptoms of aortic dissection might resemble that of a heart attack. Most people report an intense ripping pain that starts in the chest and moves to the neck and back. Aortic dissection requires immediate treatment via surgery. So if you experience this pain, let your doctor know immediately.^10,11

Can it be treated?

The ideal method of treating blood pressure difference in both arms is to identify and treat underlying conditions. If you are hypertensive, your doctor would base all treatment decisions off the arm with the higher blood pressure and aim to normalize it. Your doctor will also pay special attention to manage your risk for cardiovascular diseases.

Aortic dissection needs immediate surgical treatment to repair the aorta followed by management of blood pressure.¹¹ On the other hand, peripheral artery disease has no cure but its symptoms can be managed by lifestyle changes and drugs.⁷ 

The lifestyle changes for peripheral artery disease include quitting smoking, cutting down alcohol intake, reducing body weight, and eating a healthy diet. Your doctor may also recommend supervised exercise to see how much exercise you can do before you experience leg pain. This exercise may be a simple walk.

The drugs used for peripheral artery disease include statins to reduce bad cholesterol and anticoagulants (blood thinners) to reduce the chances of blood clot formation which could lead to a heart attack or stroke. Coexisting conditions like diabetes and hypertension also need to be treated. Sometimes you might need a surgical procedure known as revascularization to restore the flow of blood.^7,12  

When to seek medical attention?

If you measure your blood pressure at home and the difference between both arms is above 10mmHg, you should wait a while and retake it. If after a few measurements, your blood pressure difference is consistently above 10mmHg, you should contact your doctor.⁴ Measuring blood pressure in your arms one after the other can overestimate the blood pressure difference. There is also a chance that your blood pressure monitor could be faulty. So, it’s important that you confirm your blood pressure at the clinic. If your blood pressure difference is also above 10mmHg at the clinic, then you may be tested for peripheral artery disease or referred to a specialist.    

You also need to see a doctor immediately if you experience a severe pain in your chest. Let your doctor know if you experience any of the symptoms of peripheral artery disease. The symptoms of this disease develop slowly so if you experience a sudden worsening or if you develop symptoms suddenly, contact your doctor for immediate management.⁷  

Summary

It’s normal for blood pressure to vary between your arms. But if the blood pressure difference between both arms is significantly different, more than 10mmHg, you have a high risk of cardiovascular diseases. Blood pressure difference in both arms is associated with peripheral artery disease and may prompt a test for this disease at the doctor’s office.