Perhaps this has happened to you: You go to the doctor, for a checkup or a sprained ankle, and find that your blood pressure is high.

Not really high, not hypertension high, but borderline high. Say 130 over 85. Normal blood pressure is 120/80 or below, and hypertension is defined as 140/90 or higher.

Should you be worried? Is there something you can do now to ward off a later diagnosis of hypertension?

Hypertension increases your risk for heart attack and stroke, as well as for kidney disease and vision loss. And hypertension is very common: The Centers for Disease Control and Prevention estimates that one of every three American adults has the condition.

But the cardiovascular risks don’t suddenly begin at the magic number of 140/90. “It’s important to realize that there’s a continuum of risk,” says Elliott Antman, president of the American Heart Association and a cardiologist at Brigham and Women’s Hospital in Boston. “The higher the blood pressure, the higher the risk.”

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The label “prehypertension” became official when clinical practice guidelines were updated in 2003. Since then, researchers have continued to find significant risks associated with borderline high blood pressure. A 2013 review of studies encompassing more than a million people found that those with prehypertension had a 28 percent increased risk of dying from cardiovascular disease and a 41 percent increased risk of dying from stroke compared with people who had normal blood pressure.

For someone going in for a checkup, it’s important to remember that blood pressure readings are not static; they change with activity level, time of day and stress level. So a single higher-than-normal reading should not guide treatment decisions.

Doctors are well aware of a phenomenon called “white coat hypertension” — when blood pressure readings are high in the doctor’s office because a patient is nervous. (There’s an opposite case known as “masked hypertension” — when blood pressure readings are low in the doctor’s office because a patient feels particularly safe and relaxed.)

By givingnear-hypertension the label of prehypertension, doctors hope patients will take this in-between condition more seriously. It’s a warning sign and offers a chance to prevent a progression to full-blown hypertension, which requires more-aggressive treatments such as a lifetime prescription for antihypertensive drugs, which can mean a lifetime of side effects.

Domenic Sica, president of the American Society of Hypertension and an internist at the Virginia Commonwealth University Medical Center in Richmond, says he hopes that “with a diagnosis of prehypertension, people are more likely to change their health behaviors than if their doctor tells them, ‘Do this because it’s good for you.’ ”

Still, not all doctors are happy with the term “prehypertension.” “Those words, to a patient, say, ‘I don’t have to worry yet,’ ” Antman says.

What can you do about prehypertension? Healthful eating and exercise are the two biggies. Antman also recommends reducing salt in your diet.

The AHA exercise recommendation for lowering blood pressure is to get an average of 40 minutes of aerobic activity three or four times a week.

Diet recommendations include eating plenty of fruits and vegetables and choosing whole grains. The AHA also emphasizes watching your salt intake.

The average American consumes about 3,400 milligrams of salt daily, according to a 2013 Institute of Medicine report. For reducing blood pressure, the AHA sets a fairly strict goal of 1,500 milligrams per day. The American Society of Hypertension is a bit more lenient, recommending 2,300 milligrams for most people and 1,500 for those at high risk, such as people who already have hypertension and African Americans, who, studies have shown, are sensitive to the high blood pressure effects of salt consumption.

Both the AHA and the ASH recommend the DASH diet (Dietary Approaches to Stop Hypertension). “The DASH diet will help lower blood pressure, even without lowering salt,” Marla Heller, a registered dietitian who has written four bestselling books about the diet, said in an e-mail. “The first DASH study showed blood pressure reduction equal to the first-line medications at a daily sodium intake of 3300 mg of sodium.”

Experts say that people with prehypertension should monitor their blood pressure. You can do this at some physicians’ offices and drugstore kiosks; you can even buy a blood pressure cuff to use at home. (Cuffs can vary significantly in price and quality, so it’s worth doing some research.) If you’re exercising and eating better, it can be very motivating to see the positive effects in lower blood pressure numbers. In turn, that positive feedback can inspire people to stick with newly adopted healthful behaviors.