Causes of blood pressure difference between arms and legs

A 26-year woman comes to the office complaining about pain and numbness in her upper arms, exacerbated by strenuous activity. She also reports a 12-pound weight loss, joint pain and fatigue in the past six months. She has no smoking history and denies any use of illicit drugs. Her blood pressure is 143/89 mmHg in the right arm and 87/56 mmHg in the left. Her temperature is 37.6°C (99.68°F) and her heart rate is 90 bpm. Auscultation of the heart shows no murmurs and lungs are clear. The brachial pulses in her left arm are decreased compared to her right arm. No skin or mucosa lesions are identified, and the abdominal examination is unremarkable. The results of complete blood count and renal function are normal, except for mild anemia and an erythrocyte sedimentation rate (ESR) of 56 mm/hr.

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Find out what causes your blood pressure to be different in each arm and figure out which arm to use with this comprehensive guide by Flo. This article will also explain some medical conditions behind blood pressure differences.

Why do you have different blood pressure in different arms?

It is very normal for your health care provider to measure your blood pressure in both of your arms. Having different blood pressure in each arm may signal a health problem.

A blood pressure difference of a few points between arms isn’t usually a cause for concern and is quite normal. However, a difference of greater than 10 points may indicate trouble.

In younger people, a blood pressure difference between arms can happen when a muscle squeezes the blood vessel (artery) that supplies the arm. It can also happen because of a structural problem that blocks the blood from flowing smoothly through the artery.

In elderly people, a blood pressure difference between arms may indicate blocked arteries in their arms or other health issues such as diabetes.

Blood pressure difference between arms

Blood pressure is measured in millimeters of mercury (mm Hg). A difference greater than 10 mm Hg between arms (for either systolic or diastolic pressure) could indicate a circulatory problem, which may result in peripheral artery disease, stroke, or other heart problems.

People who repeatedly have different blood pressure in different arms (between 10 to 15 mm Hg systolic pressure) have an increased likelihood of developing vascular disease. Their risk of heart disease (and associated complications) is also increased.

Blood pressure higher in the right arm

It is normal to have a blood pressure difference of about five points or fewer between arms. The right arm tends to be a bit higher. According to a study published in the American Journal of Medicine, the average systolic blood pressure difference between arms is about five points. Your health care provider will make treatment decisions based on the higher blood pressure number.

A significant difference in your blood pressure readings may indicate a health issue such as:

• Peripheral arterial disease (blocked artery in your right arm)
• Diabetes
• Cognitive decline
• Heart defect
• Kidney disease

One of the less common causes of a blood pressure difference between arms is an aortic dissection, which is a tear in the aortic wall. The aorta is the largest blood vessel and supplies oxygen-containing blood to the whole body from the heart.

Blood pressure higher in the left arm

Higher blood pressure is more often found in the right arm. Having varying blood pressure in different arms is statistically normal and may not necessarily be a cause for concern. However, if the difference is persistent, your health care provider will use the arm with the higher blood pressure for all further blood pressure measurements.

Your health care provider might want to check for certain medical conditions if you have a blood pressure difference between your arms, particularly if it’s persistent and large. They might check for:

• Coarctation of the thoracic aorta
• Dissection of the thoracic aorta
• Aneurysm of the aorta
• Various kinds of extra- and intra-arterial obstruction in the upper extremities
• Takayasu disease (pulseless disease)

These causes for a blood pressure difference between arms become more likely when the arm with the lower blood pressure also has a diminished pulse.

According to studies, people with a blood pressure difference of 15 points or more between arms are twice as likely to develop peripheral artery disease. Peripheral artery disease is when your arteries become clogged or blocked by cholesterol. It affects about 12 million people in the United States. A blood pressure difference of 10 to 15 points between arms may also raise your likelihood of dying from heart disease or getting a stroke.

Which arm to choose for blood pressure measurement

According to the recommendations by the American Heart Association, the health care provider should measure your blood pressure in both your arms in case there’s a difference. Your health care provider will use the higher blood pressure number to make decisions about treatment. You should also follow the below-mentioned guidelines during blood pressure (BP) measurement:

• Avoid drinking caffeinated beverages or smoking about half an hour before BP measurement.
• Sit quietly for at least five minutes before being measured.
• During BP measurement, sit comfortably in a chair. Keep your feet on the ground and support your arm so that your elbow is at the level of your heart.
• The inflatable portion of the cuff should cover about 80 percent of your upper arm. The health care provider will place it on your skin and not over a shirt.
• Avoid talking during the measurement.

When it’s time to see a health care provider

If you have a significant blood pressure difference between arms (greater than 10 or 15 points), you should see your health care provider. If they also measure a blood pressure difference of more than 10 points between arms, they may order another test referred to as the ankle-brachial index test to rule out peripheral artery disease.

In summary

It is very common to have different blood pressure in different arms, and a difference of a few points is usually normal. A difference of greater than 10 points may indicate a health condition. Some causes of a blood pressure difference between arms include peripheral arterial disease, diabetes, heart defect, dissection of the aorta, and kidney disease.

1. https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/expert-answers/blood-pressure/faq-20058230

2. https://www.health.harvard.edu/blog/different-blood-pressure-in-right-and-left-arms-could-signal-trouble-201202014174

3. https://www.health.harvard.edu/blog/big-arm-arm-difference-blood-pressure-linked-higher-heart-attack-risk-201403057064

4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709227/

5. https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/in-depth/high-blood-pressure/art-20047889

6. https://www.health.harvard.edu/heart-health/tips-to-measure-your-blood-pressure-correctly