Why You Should Check Blood Pressure in BOTH Arms

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Do you check your blood pressure in both arms? You should, according to researchers from the University of Exeter. They measured the blood pressure in both arms of 3350 healthy people, aged 50 to 70 years, with no previous history of vascular disease. After this one-off reading, the volunteers were followed for just over 8 years to see how they fared.

A different blood pressure in both arms is a warning sign

Astonishingly, over 60% of people taking part had more than a 5mmHg difference in systolic blood pressure between their two arms. What’s more, having a different blood pressure in both arms was associated with worse long-term outcomes.

Whether or not they had hypertension, those with a different blood pressure in each arm were 91% more likely to die over the 8 year follow-up period than those with no difference in blood pressure between their arms.

They weren’t just more prone to circulatory conditions such as heart attack or stroke – they were 44% more likely to die from any medical cause overall. And this was even if their blood pressure was initially in the normal range.

For those who did have hypertension at the time of BP measurement, a greater than 5mmHg difference in systolic blood pressure between both arms almost tripled their risk of dying from cardiovascular disease over the follow-up period.

Overall, there was a 2.6 fold increased risk of heart attack or stroke, rising to a three-fold increased risk for those with a greater than 10mmHg difference in systolic blood pressure between their two arms.

Why a different blood pressure in both arms is harmful

It’s now thought that a simple, one-off blood pressure measurement in both arms can help to pinpoint people with significant hardening and furring up of the arteries on one side of the body, which suggests their circulatory health is not as good as it could be.

Guidelines already suggest that doctors should measure your blood pressure in both arms when assessing you for hypertension, but this extra step is often skipped due to lack of time, lack of awareness, or a false sense of security because the reading in the first arm is fine.

If you know you have a higher blood pressure in one arm than the other, your doctor can provide more targeted treatment to reduce your long-term risks. It is even more important to ensure your blood pressure is well-controlled and that other risk factors such as a raised LDL-cholesterol or a raised glucose level are kept within the normal range.

Diet and lifestyle measures are also key – even if you don’t have pre-existing heart disease or hypertension. Eat more fruit, vegetables, oily fish and other foods good for your blood pressure. Cut back on salt, and ensure good intakes of calcium, magnesium, potassium, vitamin C and vitamin D.

Exercise every day, and use relaxation techniques such as aromatherapy, meditation, reflexology and music therapy to help lower blood pressure by reducing stress in your life.

BldpressSo, next time you have your blood pressure measured by a healthcare professional, ask them to check the reading in both arms. It’s also a good idea to buy a home arm blood pressure monitor and keep an eye on your blood pressures yourself.

You can assess your own risk of heart disease based on other factors, at this link.

Image credit: niekverlaan/pixabay; geralt/pixabay


About DrSarahBrewer

Dr Sarah Brewer MSc (Nutr Med), MA (Cantab), MB, BChir, RNutr, MBANT, CNHC qualified from Cambridge University with degrees in Natural Sciences, Medicine and Surgery. After working in general practice, she gained a master's degree in nutritional medicine from the University of Surrey. Sarah is a registered Medical Doctor, a registered Nutritionist and a registered Nutritional Therapist. She is an award winning author of over 60 popular self-help books and a columnist for Prima magazine.


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5 thoughts on “Why You Should Check Blood Pressure in BOTH Arms

  • Alan

    Hi Sarah, Fascinatiing stuff and a source of worry for the likes of me with a persistent systolic inter-arm difference of 15-20 mm Hg!
    However, looking at the original research paper, it seems to me that these researchers tried to imply that they’ve found a significant result when they probably haven’t. Any A-level Maths student will know that confidence intervals that include 1.0 are not statistically significant and all of the results have a CI including 1.0 showing it could have happened by chance…….Perhaps you could throw some light on this and correct me if I’m wrong.

    • DrSarahBrewer Post author

      Hi Alan, most of the confidence intervals do not cross 1, which is the key point. For example, a confidence interval of 0.97 to 1.07 does cross 1 (unity) so could occur by chance alone. A confidence interval of 1.05 to 1.20 does not cross one so is accepted as having a low probability (usually less than 5% depending on how the study was designed) of occuring by chance alone (but doesn’t rule chance out entirely – a different population could show different results). So in this particular study, an interarm difference of ≥5 mmHg was associated with an increased cardiovascular mortality (adjusted hazard ratio [HR] 1.91, 95% confidence interval [CI] = 1.19 to 3.07 which does not cross one), and all-cause mortality (adjusted HR 1.44, 95% CI = 1.15 to 1.79) which does not cross one. Within the subgroup of 764 participants who had hypertension, inter arm differences of ≥5 mmHg or ≥10 mmHg were associated with both cardiovascular mortality (adjusted HR 2.63, 95% CI = 0.97 to 7.02 (which does cross one, so could have occurred by chance alone) but the adjusted hazard ratio of 2.96, 95% CI = 1.27 to 6.88 does not cross one, so is deemed statistically significant. Similarly, both the all-cause mortality (adjusted HR 1.67, 95% CI = 1.05 to 2.66, and adjusted HR 1.63, 95% CI = 1.06 to 2.50) do not cross one. Interestingly, an inter-arm difference of ≥15 mmHg was not associated with survival differences in this study. If you are concerned, however, do ask to be referred to a cardiologist. They all now measure blood pressures in both arms on sitting and standing, so this study, and others, have had a major effect on clinical medical practice. Hope that helps, Sarah B

      • Alan

        Hello Sarah, Many thanks for your detailed explanation. Good of you to take the time. I’d obviously got hold of the wrong end of the numbers stick! By the look of it, I should be thankful my inter-arm BP difference is greater than 15, but I’m off to find a tame cardiologist anyway. Thanks again, Alan

  • Dan

    Wow, that is news to me, I’d only ever heard of checking your blood pressure in the left arm as it gets a stronger reading. How often would you suggest checking blood pressure? Also I’ve heard the electric readers aren’t as accurate, do you know if this is the case.
    great post and a real eye opener.

    • DrSarahBrewer Post author

      Hi Dan, If your blood pressure is raised or borderline, then check as often as your doctor recommends – if uncontrolled you may need to check a couple of times a day until it’s at an acceptable level all the time. If your BP is fine, you can check once a year to see if it’s slowly creeping up – though some guidelines suggest every 3 or even 5 years is ok I think that’s not often enough. As long as your upper arm or wrist BP monitor is validated (and recalibrated as often as the manufacturer recommends) it will give an accurate reading. Here’s my advice on choosing a blood pressure monitor. Hope that helps.