Why Blood Pressure Should Be Measured in Both Arms

Ian C. Langtree - Writer/Editor for Disabled World (DW)
Published: 2016/02/28 - Updated: 2025/06/01
Publication Type: Informative
Category Topic: Medical Research and News - Academic Publications

Page Content: Synopsis - Introduction - Main - Insights, Updates

Synopsis: This information reviews medical research showing that significant differences in blood pressure readings between arms can signal underlying health conditions, such as artery blockages, diabetes, heart defects, or kidney disease. Drawing from large-scale studies published in reputable journals like the American Journal of Medicine and The Lancet, the article explains that an arm-to-arm systolic difference of more than 10 mm Hg is linked to a higher risk of heart attack, stroke, and cerebrovascular disease, with a 15-point difference increasing stroke risk by 60%. The article emphasizes the clinical importance of measuring blood pressure in both arms, recommending that future readings and treatment decisions be based on the arm with the higher measurement. This guidance is especially useful for seniors and people with disabilities, who may be at greater risk for vascular disease and could benefit from early detection of silent, symptomless conditions. The authority of this information is supported by its foundation in peer-reviewed research and the expertise of its author, a recognized advocate in disability health communication - Disabled World (DW).

Introduction

Small differences in blood pressure readings between the right and left arm are normal. But large ones suggest the presence of artery-clogging plaque in the vessel that supplies blood to the arm with higher blood pressure.

Main Content

What Exactly is Blood Pressure?

Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels and constitutes one of the principal vital signs. The pressure of the circulating blood decreases as blood moves through arteries, arterioles, capillaries, and veins; the term blood pressure generally refers to arterial pressure, i.e., the pressure in the larger arteries, arteries being the blood vessels which take blood away from the heart. Blood pressure is always given as two numbers;

• Systolic Pressure (when the heart beats)
• Diastolic Pressure (when the heart relaxes)

Blood pressure measurements are written one above, or before, the other with the systolic being the first number, e.g. BP 120/80.

Blood pressure measurement is NOT the same as your heart rate (pulse) or maximum heart rate measurement. Check what your heart rate for your age should be. You can calculate your predicted maximum heart rate by using the calculation: 220 - (age) = Age Predicted Maximum Heart Rate - or see our Target Heart Rate Calculator and Chart.

In a study(1) researchers reviewed some 3,390 people who were over the age of 40 and who did not originally have cardiovascular disease.

• The average arm-to-arm difference in the study was about 5 points in systolic blood pressure (the first number in a blood pressure reading).
• About 10% of the study participants had differences of 10 or more points (10 millimeters of mercury (mm Hg)).

Over the next 13 years or so, people with arm-to-arm differences of 10 points or more were 38% more likely to have had a heart attack, stroke, or a related problem than those with arm-to arm differences less than 10 points. The findings appear in the March 2014 American Journal of Medicine.

• A blood pressure difference of 10 to 15 points or more between arms also boosted the chances of having a stroke or dying from cardiovascular disease.
• A 15 point difference in systolic readings also increased the risk of cerebrovascular disease by 60%.

Cerebrovascular disease is associated with thinking problems, such as dementia, and increased risk of stroke. These results were published in The Lancet.

In general, any difference of 10 mm Hg or less is considered normal and not a cause for concern. A difference of more than 10 millimeters of mercury (mm Hg) for either your systolic pressure (top number) or diastolic pressure (bottom number) may be a sign of an underlying problem such as:

• Diabetes
• Heart defects
• Kidney disease

The arteries under the collarbone supply blood to the arms, legs and brain. Blockage can lead to stroke and other problems, the researchers noted, and measuring blood pressure in both arms should be routine. Blocked arteries in your arms, called peripheral artery disease, shows no physical symptoms, so without testing for a significant difference in blood pressure between a patient's arms, this silent killer can go unnoticed for years.

Doctors should routinely compare your blood pressure readings from both arms. If your blood pressure in one arm is higher than the other, that arm should be the one upon which to base any treatments and to check your blood pressure in the future.

If you're worried about your blood pressure or cardiovascular risk, speak to your GP or practice nurse.

Reference:

(1) - www.amjmed.com/article/S0002-9343%2813%2900972-8/fulltext

You can learn more about blood pressure, and view a chart of what your blood pressure reading should be according to your age here.

Insights, Analysis, and Developments

Author Credentials: Ian is the founder and Editor-in-Chief of Disabled World, a leading resource for news and information on disability issues. With a global perspective shaped by years of travel and lived experience, Ian is a committed proponent of the Social Model of Disability-a transformative framework developed by disabled activists in the 1970s that emphasizes dismantling societal barriers rather than focusing solely on individual impairments. His work reflects a deep commitment to disability rights, accessibility, and social inclusion. To learn more about Ian's background, expertise, and accomplishments, visit his full biography.