Most people don't know what normal or healthy blood pressure is, a study shows

Most people don't know what normal or healthy blood pressure is, a study shows

Many Americans do not know the upper limit of normal or healthy blood pressure levels, even though they believe they do. A healthy blood pressure value is below 120/80 mmHg. More than half of adults in the U.S. live with high blood pressure, which is a major risk factor for stroke and heart disease.

Blood pressure readings are a standard part of both routine and urgent health care visits — but most Americans don't know what constitutes a normal or healthy blood pressure reading, new research shows.

The news comes from a study published in the journal last monthMedical decision makingwho found that the majority of Americans, although confident in their blood pressure knowledge, did not know the upper limit for normal or healthy blood pressure levels, which is 120/80 mm Hg (millimeters of mercury).

"Blood pressure is measured at almost every doctor's visit, but in practice there is little rudimentary education about blood pressure because visits often focus on other topics, typically whatever a patient is presenting with," lead study author Wändi Bruine de Bruin, PhD, provost professor of public policy, psychology and behavioral sciences at the University of Southern California, tellsHealth.

More than half of U.S. adults live with hypertension or high blood pressure, but only about a quarter of those people have it under control. And while it's a common condition, it's also deadly — high blood pressure increases the risk of heart disease and stroke, two leading causes of death for Americans.

But since high blood pressure typically doesn't cause any symptoms (it's often called the "silent killer"), the only real way to know if you have it is through routine blood pressure readings—and even then, personal knowledge of normal or healthy blood pressure readings can either help or hinder future health outcomes.

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Overreliance on blood pressure readings may result in delayed treatment

For the new study, Bruine de Bruin and her team surveyed more than 6,500 U.S. adults about their knowledge of blood pressure measurements and their confidence in that knowledge.

The sample included 1,342 adults with hypertension without comorbidities and 795 with hypertension with comorbidities such as heart disease, kidney disease, or diabetes; the authors adjusted for socioeconomic status, education level, and hypertension diagnosis.

Overall, 64% of respondents reported confidence in their knowledge of blood pressure levels - but only 36% correctly stated that 120/80 mmHg was the upper limit for a healthy or normal blood pressure level.

The discrepancies between people feeling confident in understanding the readings and accurately identifying healthy readings were even greater in the high blood pressure groups. Of those who only had high blood pressure, 78% were confident they understood the readings, while only 47% did. Among participants with hypertension and comorbidities, 81% were confident they understood, while only 40% were correct.

The researchers also found that patients who were confident they understood blood pressure readings were more likely to say they would seek interventions for stage 2 hypertension readings, but were less likely to take the same actions for stage 1 readings.

According to researchers, this overconfidence – and therefore lack of willingness to take action – could negatively impact their health.

"The most worrying finding is that most people don't know what normal or healthy blood pressure is," said Bruine de Bruin, "but they are confident that they know, and that can undermine their willingness to seek treatment."

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Blood pressure measurement, explained

Blood pressure readings include two numbers. The first, systolic blood pressure, measures the pressure in your arteries as your heart beats and pushes blood throughout the body. The second, diastolic blood pressure, measures the pressure in your arteries between beats. In general, the lower the numbers, the better.

The American Heart Association and the American College of Cardiology updated the threshold for healthy blood pressure in 2017 after the SPRINT (Systolic Blood Pressure Intervention Trial) clinical trial determined the upper threshold for healthy blood pressure to be less than 120/80 mm Hg.

(This is lower than previously thought, and it is common for clinics to use the old threshold of 130/80 mm Hg, said Willie E. Lawrence Jr., MD, FAHA, FACC, a cardiologist and medical director of the Center for Better Health and Wellness in Benton Harbor, Michigan.)

Current blood pressure categories

Normal/Healthy:Less than 120/80 mmHg

Increased:120-129 and less than 80 mm Hg

Stage 1 high blood pressure:130-139 or 80-89 mmHg

Stage 2 high blood pressure:140 or higher or 90 or higher mm Hg

Hypertensive crisis:Higher than 180 and/or higher than 120 mm Hg

But even healthcare professionals can – and often do – get inaccurate readings. “Most clinics do a terrible job of taking blood pressure,” said Dr. Lawrence and noted that it is important for patients to learn about the proper way to take blood pressure so they can advocate for themselves in the clinic.

To obtain an accurate blood pressure reading, healthcare providers should wait five minutes after the patient moves from the waiting room to the exam room before taking the reading, Dr. Lawrence. Best practices also include ensuring that the patient's legs are uncrossed and that their arm is at the same level as the device. You should also not have a full bladder, talk or actively listen to someone, have an unsupported back, or use a cuff that is too small.

"The patient needs to know what doctors should do, it's about their health," said Dr. Lawrence, adding that patients should feel comfortable asking their doctor to correct any errors.

If you're using a home device to check your blood pressure, Dr. Lawrence first start with a validated device.

"If you don't start with a validated home measurement device, you're unlikely to achieve good blood pressure control," he said.

The website validatebp.org has a list of tested and validated home blood pressure monitors. If you want to monitor yourself at home, Dr. Lawrence, to start here and then follow the same instructions — sitting quietly in a quiet room, not talking, making sure your cuff isn't too small — to ensure an accurate reading.

After that, understanding what the healthy thresholds for high blood pressure are will help a patient advocate for themselves when their reading is high.

“As a patient, it is important to know what the limits are, so if you find out in the doctor's office that you are above these limits, you can address this during your visit,” said Bruine de Bruin.

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High blood pressure is reversible

As people age, their arteries and blood vessels stiffen, making high blood pressure more common, Dr. Lawrence. This is practically inevitable; But diet, exercise and comorbidities, particularly diabetes, all increase a person's risk of developing high blood pressure, and lifestyle changes are almost always part of treatment.

"The basis for high blood pressure is lifestyle intervention. But for people who had bad habits that predisposed them to high blood pressure, maintaining new habits can be difficult," said Dr. Lawrence. “You’re not going to change these numbers overnight.”

For this reason, most people whose blood pressure levels fall into Level 1 or higher also require medication. The general guideline is one medication that relaxes blood vessels for stage 1 hypertension and two medications—usually diuretics, beta-blockers and alpha-blockers, calcium channel blockers, or ACE inhibitors—for stage 2.

"People may think they are a failure if they can't change blood pressure through lifestyle changes, but we need to treat high blood pressure as the chronic disease it is, which means treating it with the medications it needs," said Dr. said Lawrence. “This is not a failure.”