Odds Are, They're Taking Your Blood Pressure All Wrong

By Richard Harris

Published November 20, 2017 at 4:58 AM EST

Emily Blair, a medical assistant at the Colon, Stomach and Liver Center in Lansdowne, Va., takes a blood pressure reading for Robert Koenen. New guidelines say that patients should have their arm resting on a surface while taking a reading and both feet should be placed flat on the ground.

When was the last time you were asked to sit without saying a word for five minutes before your blood pressure was measured? If your answer was "I never remember doing that," you're in good company.

Yet that is one of the many rules that medical professionals are supposed to follow when measuring your blood pressure.

Paul Whelton, a cardiovascular specialist at the Tulane University School of Public Health, says airplane pilots always run down a safety checklist before taking off. "We would be shocked if a pilot told us he was in a rush and just didn't have time to do it."

Yet he says clinicians aren't taking enough care to make an important measurement when it comes to health: reading blood pressure values.

That is topical right now because Whelton is among a group of physicians who have just recommended new standards for blood pressure. Now, if your blood pressure tops 130 over 80, you are in unhealthy territory. Having an accurate measure is important because more people than ever may be keeping a close eye on their blood pressure and trying to keep it in a healthy range through diet, exercise and potentially medications.

The new guidelines from the American Heart Association and the American College of Cardiology, released Tuesday, which lowered the threshold for diagnosing high blood pressure from 140/90, mean that nearly half of the U.S. population will be considered as having high blood pressure, with the greatest impact on younger people.

So Whelton and his committee members rolled out a checklist for medical professionals to follow when they're taking your blood pressure. Here are the do's and don'ts from a patient's perspective, aimed at making it less likely that you'll get a reading that is falsely high, or low:

Do: Sit in a chair, feet flat on the ground, legs uncrossed, with your back supported and without talking, for at least five minutes before you get your blood pressure measured.

Don't: Exercise, consume caffeine or smoke within 30 minutes of your test.

Do: Empty your bladder before your blood pressure is taken.

Don't: Sit or lie on the exam table. Whelton says that can result in a falsely low blood pressure reading.

Do: Roll up your sleeve so the blood pressure cuff rests on bare skin, not clothing.

Don't: Let your arm dangle or rest in your lap during the reading. It should be supported on a surface such as a desk.

If your blood pressure appears high, your doctor's office should take a reading in both arms. And next time you come in, the reading should be from the arm that showed the higher blood pressure.

There is no single number that determines your blood pressure — it can vary throughout the day and be influenced by something as simple as being approached by a well-meaning nurse carrying a blood pressure cuff. So the new checklist says the diagnosis of high blood pressure requires at least two readings on separate occasions.