‘Masked’ hypertension: You may have high blood pressure and not even know, docs warn

Have you ever heard of masked hypertension? Doctors warn you may have high blood pressure and not even know it.
Have you ever heard of masked hypertension? Doctors warn you may have high blood pressure and not even know it. File/ Getty Images

You take a deep breath to relax yourself, then your doctor checks your blood pressure. That may be how you’re screened for hypertension but new research is warning that a normal blood pressure reading at your checkup may be too quick, masking a real problem with your health.

Doctors are shedding light on what’s called “masked hypertension” – when a patient’s blood pressure readings are normal at the doctor’s office but increase at other times of the day.

It’s the reverse of “white-coat hypertension,” which is when patients experience a spike in their blood pressure when they’re nervous at the doctor’s.

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Now, scientists out of Columbia University and Stony Brook University say “masked hypertension” is much more prevalent than doctors think and it should be addressed before serious high blood pressure cases go unnoticed. The condition is “easy to miss.”

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Your best bet for a better read is ambulatory monitoring, an around-the-clock screening of blood pressure for 24 hours. That way, doctors can get a better pulse on what’s really going on with your health, they say.

Ambulatory blood pressure is taken when you’re walking around, running errands, driving and even at work. Patients wear a blood pressure cuff on their arm, attached to a small, portable device. The results are much more comprehensive than the quick reading at the doctor’s office, the researchers say.

For their study, the U.S. scientists looked at 888 people between 2005 and 2012. They had their blood pressure tested three times in clinic along with one 24-hour ambulatory test that checked blood pressure 30 minutes. No one was taking medication or diagnosed with high blood pressure.

READ MORE: Canada’s baby boomers face ‘dangerous levels’ of high blood pressure: report

They found that 15.7 per cent of patients with a normal blood pressure at the doctor’s office has “masked hypertension” when they tried day-long monitoring.

This was more common in men than women and in people with borderline hypertension.

Younger people with a normal weight were more likely to have higher day-long readings over a quick clinic test.

“These findings debunk the widely held belief that ambulatory blood pressure is usually lower than clinic blood pressure,” Dr. Joseph Schwartz, the study’s lead author said.

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“It is important for health-care providers to know,” he warned.

READ MORE: Why measuring your blood pressure matters – even for teens

He said the findings reveal a “substantial number” of healthy people who have masked hypertension that needs to be addressed.

High blood pressure means there is too much pressure in your blood vessels. This can damage your blood vessels, putting you at risk of a handful of health problems.

It’s like pumping too much air into a tire or balloon, Hypertension Canada explains on its website.

Anyone can develop high blood pressure but it becomes more common as you get older, according to the organization.

READ MORE: Why measuring your blood pressure matters – even for teens

It estimates that 7.5 million people in Canada are living with hypertension. If you don’t monitor your blood pressure, you could be at risk of stroke, heart attack and kidney disease, among other chronic issues.

The U.S. study will be published in the American Heart Association’s journal Circulation.