Confused about how low your blood pressure should really be? That’s understandable, considering the many headlines that a major new study has generated.

The study, dubbed the Systolic Blood Pressure Intervention Trial, or SPRINT, suggests that a blood pressure level that is much lower than what is currently recommended for some people can significantly cut the risk of heart failure and death from heart problems. That's prompted some experts to suggest new blood pressure guidelines for who needs to take medication, and how low their levels should go.

But many experts, including our own at Consumer Reports Best Buy Drugs, say it’s unknown whether the SPRINT findings are relevant for most people with high blood pressure. That’s because the study looked only at a small, high-risk subset of hypertension sufferers.

Old Questions, New Answers

If you’ve received a hypertension diagnosis, it’s important to keep your blood pressure at a healthy level. Uncontrolled high blood pressure leads to more heart attacks and strokes in the U.S. than any other cause. But how low is low enough?

Under current guidelines, the ideal is a systolic pressure (top number) of 120 millimeters of mercury or less and a diastolic pressure (bottom number) of 80 mmHg or less. You’re considered to have high blood pressure if the systolic hits 140 or the diastolic goes to 90 or above. But experts have long debated whether those with high blood pressure need to get their levels all the way down to the ideal or whether somewhere below the cutoff for high blood pressure is fine.

The SPRINT study sought to end this debate, and at first glance, the results suggest that lower is healthier. Here’s why: The government-funded trial involved more than 9,300 people with elevated blood pressure and a high risk of heart attack. They were given medication to reduce their blood pressure. About half aimed to lower their systolic pressure to 120; the other half stuck with a goal of 140.

The study was slated to run for five years but was stopped after slightly more than three years because results were so dramatic. During that time, 65 people in the group aiming for a systolic pressure of 140 died and 100 developed heart failure. Of those trying to get down to a systolic of 120, only 37 died and 62 developed heart failure, researchers reported in the New England Journal of Medicine.

Gary Gibbons, M.D., director of the National Heart, Lung, and Blood Institute (NHLBI), SPRINT’s primary sponsor, says the findings will prompt new blood pressure guidelines and save lives.

But the benefits came with significant downsides. To get their blood pressure to 120, people in the study had to take three blood pressure medications on average. That led to almost double the instances of serious side effects, including some that required emergency care at a hospital, such as kidney failure, dangerously low blood pressure, and imbalances in potassium or sodium blood levels.

Also, many people find it difficult to take their blood pressure medication consistently, and an additional pill may increase that challenge, notes Michael Pignone, M.D., chief of internal medicine at the University of North Carolina School of Medicine in Chapel Hill. In fact, because of side effects, the need to cut costs, and/or other factors, up to one-half of people stop taking their high blood pressure medication within one year. “Putting somebody on more medications if they’re not consistently taking their current regimen is not a helpful strategy,” Pignone says.

Who's Affected

SPRINT focused on a specific group of people with hypertension: those 50 and older with at least one other chronic condition, such as heart disease or kidney disease (both raise heart attack and stroke risks), and those 75 and older. Only about one in six people with high blood pressure is in such a high-risk group.

If you are, talk with your doctor about whether lowering your systolic blood pressure to 120 is worth the risk, says Harlan Krumholz, M.D., a cardiologist at Yale University. Otherwise, he adds, you may not need to lower your goal to 120, based on these new findings.

Talk with your doctor about making important lifestyle changes that can help reduce blood pressure (see “Make Lifestyle Changes First,” below). Those are especially important for people like those in the group studied in SPRINT.

For the Rest of Us

If you’re not in one of the previously mentioned high-risk categories, what should your blood pressure levels be? Our medical experts consider 150/90 a reasonable goal for most people 60 to 75 who don’t have other risk factors. They suggest a goal of 140/90 for people younger than 60, those with diabetes, and those younger than 50 with chronic kidney disease.

Those numbers are based on recommendations from an independent expert panel convened by the NHLBI. The panel notes that achieving levels below 140/90 can require additional blood pressure drugs or high doses. That increases the risk of previously mentioned side effects, and—depending on the drugs—problems such as persistent coughing, erectile dysfunction, and frequent urination.

But Be Sure of Your Numbers

Uncertain about your blood pressure level? Get it measured, even if you think it’s fine. The U.S. Preventive Services Task Force recommends that everyone 18 and older be screened for hyper­tension. Having high blood pressure generally causes no obvious symptoms, so an estimated one-fifth of American adults with the problem don’t know they have it.

Surprisingly, the most accurate way to measure your blood pressure is not at your doctor’s office. Up to 30 percent of people receive an incorrect diagnosis of high blood pressure, often because their blood pressure is normal at home but spikes in a doctor’s office—perhaps because of anxiety. Blood pressure can also fluctuate depending on factors such as sitting position, bladder fullness, and placement of the monitor’s cuff.

The gold standard method for measuring blood pressure—known as ambulatory monitoring—involves wearing a small, portable device that records your blood pressure at frequent intervals over 24 hours. But that monitoring, prescribed by your doctor, isn’t widely available, and insurance might not cover the cost. A good alternative, the task force says, is a home blood pressure monitor. Record levels once in the morning and once in the evening for a week.

Make Lifestyle Changes First

If your systolic level is moderately elevated (150 to 160 for people 60 and older, 140 to 150 for others) and you are otherwise at low risk for heart disease, try lifestyle changes before considering medication.

Losing weight, exercising more, cutting back on sodium, quitting smoking, and limiting alcohol to no more than two drinks (24 ounces of regular beer, 10 ounces of wine, or 3 ounces of 80-proof whiskey) per day for most men, and no more than one daily drink for women can lower your blood pressure and sometimes allow you to reduce your drug dosage or eliminate your need for it. Consider medication only if your blood pressure hasn’t dropped enough after six months of lifestyle changes.

And if you do end up needing medication, it’s important to continue those healthy habits.

Editor's Note: This article also appeared in the February 2016 issue of Consumer Reports On Health.

This article and related materials are made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by the multistate settlement of consumer-fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).