A woman checks her blood pressure using a monitor at home.

A little more than a year ago, the blood pressure guidelines were updated. This meant that 31.3 million more Americans were newly considered to have high blood pressure.

The problem, say experts, is that a lot of those consumers—and their healthcare providers—weren’t sure whether they were supposed to start taking blood-pressure-lowering drugs.

"Whenever there’s a major shift like that, it’s a culture change," says Michael Hochman, M.D., director of the Gehr Family Center for Health Systems Science at the Keck School of Medicine at USC. "It just takes a little bit of getting used to."

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But some confusion still lingers, says Andrew Moran, M.D., associate professor of medicine at Columbia University Medical Center.

Under the new guidelines, you have hypertension if you have blood pressure of least 130 for the systolic (top) number or 80 for the diastolic (bottom) number. Previously, the number that put you in the high blood pressure category was 140/90. 

Keeping to the lower levels may save lives. For example, one study published late last year in Circulation estimated that if all U.S. adults age 45 and older were able to keep their blood pressure below 130/80, it would prevent 3 million strokes and heart attacks over a decade.

“A blood pressure level between 130-139/80-89 doubles your risk of cardiovascular complications such as a heart attack compared to people whose blood pressure is under 120/80,” says Paul Whelton, M.D., lead author of the guidelines and the Show Chwan professor of global public health at the Tulane University School of Public Health in New Orleans. That’s because damage to blood vessels begins as soon as blood pressure is elevated.

Here, a quick guide to the numbers you should know and whether you need meds.

1. Know Your Blood Pressure Numbers

The updated guidelines put blood pressure readings in five different categories:

• Normal. A top number less than 120 and a bottom number less than 80.
• Elevated.
A top number between 120 and 129, and a bottom number less than 80.
• Stage 1.
 A top number between 130 and 139, or a bottom number between 80 and 89.
• Stage 2.
A top number of 140 or higher, or a bottom number of 90 or higher.
• Hypertensive crisis.
A top number over 180 or a bottom number over 120. 

It’s important to know where your numbers fall—and all too many people don’t. Even before the 2017 recommendations were issued, 13 million Americans were walking around with undiagnosed high blood pressure, according to the Centers for Disease Control and Prevention.

Left unchecked, excessive pressure can damage blood vessels throughout the body and increase your risk not only for heart attacks and strokes, but also for heart failure, kidney damage, vision loss, and arterial blockages. But if hypertension is detected early, you can adjust course before the damage occurs.

So, have your blood pressure checked at least once every two years, and more often if you’re 50 or older or have other risk factors for hypertension. For most people, it’s a good idea to have it done every time you visit a healthcare provider.

If your initial reading is elevated, don’t panic. That can be due to a number of factors, including stress or caffeine. If your blood pressure is high and you have no history of high readings, your doctor may take another reading after about 5 minutes and, if that's still high, another in a couple of weeks to confirm.

You might want to consider a home blood pressure monitor. Sometimes, people who have high blood pressure at their doctor’s office actually have normal blood pressure in other settings, like at home, a condition known as “white-coat hypertension.” And if you are diagnosed with high blood pressure, a home monitor may help you get it under control.

Take a look at these recommended blood pressure monitors from CR’s tests:

Quick Take
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Unlock Blood Pressure Monitors Ratings

2. Make Lifestyle Changes First

A slightly elevated reading doesn’t mean that you should consider medication, but it does mean you should make some broad-based lifestyle changes, says Mary Norine Walsh, M.D., president of the American College of Cardiology and a cardiologist at St. Vincent Heart Center in Indianapolis. Lifestyle changes are in order if your blood pressure is over 120/80 (which used to be considered normal), she adds.

Regular exercise can lower your systolic pressure by up to 9 points, and losing 11 pounds can reduce it by 2.5 to 10 points. Avoiding excess sodium (anything beyond 2,400 mg in a day) can also lower it between 2 and 8 points in some people.  

3. Consider Drugs Carefully

If your blood pressure is considered “elevated,” you should employ the lifestyle strategies above to lower your numbers.

And even if your blood pressure is considered “stage 1”—130-139/80-89—you should still generally try lifestyle changes first.

The new guidelines don’t recommend that everyone now considered to have stage 1 hypertension receive drugs to lower blood pressure—only those who already have cardiovascular disease or are at a high risk for it.

Note that drug treatment to lower blood pressure is only associated with a reduced risk of death and cardiovascular disease in people whose baseline systolic blood pressure is 140 or higher, according to a review of the research published last year in the journal JAMA Internal Medicine. There’s no strong evidence that medication will help people with lower blood pressure numbers.

So, talk with your doctor about your overall risk level for heart disease, and whether you should be taking blood pressure lowering drugs or not.

4. Take Meds With Care

One sometimes overlooked aspect of the new blood pressure guidelines is that doses might need to be raised for people who are already on medications—to help them meet the lower targets for blood pressure, Moran says.

More aggressive treatment should only be undertaken "after making a sustained effort with the lifestyle changes” first, however, Hochman notes. That's because higher doses, or even adding a drug to your regimen, can hike the risk of potential side effects such as impaired kidney function, or dizziness, which can increase the likelihood of falls, especially in older adults.

When doctors work to reduce the blood pressure of seniors too aggressively, for example, they put them at a “heightened risk for falls and fractures,” says Steven Nissen, M.D., chairman of cardiovascular medicine at the Cleveland Clinic.

“It’s best to be super cautious, especially among the elderly," Nissen adds. "I personally start with the lowest dose of medication possible and then reassess in a couple of weeks."

And according to the new Circulation study’s predictions, with more people taking hypertension drugs or receiving higher doses of those drugs, we might also see more than 3 million more adverse events from drug side effects.

It usually makes sense to start with the oldest, safest, and least expensive drug: diuretics, or water pills, such as chlorthalidone or hydrochlorothiazide.

These can drive up blood sugar levels, however, Nissen says. So if you have type 2 diabetes or are at risk for it, you may need to be monitored closely by your doctor or consider another drug, such as an ACE inhibitor or calcium channel blocker.

If you notice side effects, it’s important to alert your doctor. But don’t just stop taking your medications on your own.

Most side effects are manageable compared with the serious consequences of high blood pressure like heart attack and stroke, according to Circulation study author Adam Bress, Pharm.D., assistant professor at the University of Utah School of Medicine.

If you’ve been on medication for a while and have gotten your blood pressure to target levels, consider talking to your doctor about lowering your dose, especially if you’ve implemented other lifestyle changes such as weight loss and exercise.

Catherine Roberts contributed additional reporting to this story.