Prehypertension: High Blood Pressure’s Warning Sign

What you need to know if you’ve been diagnosed with elevated blood pressure.

You’re at the doctor getting your blood pressure tested, and the reading comes back: You have prehypertension, a warning sign that you might have hypertension—high blood pressure—in the future.

High blood pressure can put you at greater risk of heart attack, stroke and other life-threatening complications. So, what can you do to stop prehypertension from becoming full-on hypertension? We talked to UNC Health Care internal medicine physician Robert Hutchins, MD, MPH to learn more.

A Word About the Numbers

Blood pressure is measured using two numbers. The first or top number is called systolic blood pressure, and it measures the pressure in your blood vessels when your heart beats. The second or bottom number is called diastolic blood pressure, which measures the pressure in your blood vessels when the heart rests between beats.

For years, hypertension was classified as a blood pressure reading of 140/90 mmHg or higher. In 2015, a clinical study called the Systolic Blood Pressure Intervention Trial (SPRINT) found that lowering the guidelines for hypertension helped better prevent cardiovascular problems in people with a higher baseline risk for cardiovascular disease. Those at risk could be treated earlier—and, as a result, had better outcomes.

The updated guideline classifies hypertension as a blood pressure reading of 130/80 mmHg or higher. For example, people who previously had blood pressures of 130 over 82, which was not considered high blood pressure, are now hypertensive by the new measure.

The change in hypertension guidelines means the threshold for prehypertension has also changed. You now are considered prehypertensive if you have a systolic reading of 120 mmHg to 139 mmHg or a diastolic reading of 80 mmHg to 89 mmHg.

“After that study came out, the treatment paradigm for high blood pressure, whether it was prehypertension or hypertension, changed because the threshold changed,” Dr. Hutchins says. “If you lower the threshold for what you’re calling hypertension, you end up capturing a lot more people in that group of prehypertensive patients.”

Lifestyle Changes That Help Lower Blood Pressure

If you’ve been diagnosed with prehypertension, your doctor may suggest lifestyle changes to lower your blood pressure. Dr. Hutchins says that while it may be difficult, making dietary changes and exercising more often can help prevent hypertension.

When it comes to nutrition, he recommends the Mediterranean or DASH (Dietary Approaches to Stop Hypertension) diets. The Mediterranean diet is based on Mediterranean food culture, with the DASH diet being a slight adaptation of that diet. With both, you eat fruit, vegetables, whole grains, nuts and legumes, along with fish and chicken. Red meat and dairy products are allowed but should be eaten less often. Instead of salt, use herbs and spices for flavor and olive oil instead of butter. Both diets also limit alcohol intake.

Dr. Hutchins also suggests at least an hour and a half or two hours per week of aerobic (cardio) and anaerobic exercise (weights or resistance training).

Lastly, see your doctor more often. “For people with elevated blood pressure, I usually have them check their blood pressure at home for a few months, and then follow up with me to see if it’s still elevated at home, away from the stress of the doctor’s office,” Dr. Hutchins says. “This way, we can see if they really have high blood pressure and also determine if any lifestyle changes they might be engaging in are improving their blood pressure.”

Treatment for Prehypertension  

If you continue to have elevated blood pressure, then your doctor will start you on blood pressure medication.

“If you truly do have high blood pressure, it’s best not to let it remain that way for too long, especially if you have other risk factors for cardiovascular disease, such as high cholesterol, metabolic syndrome, and/or or elevated blood sugar,” Dr. Hutchins says. “Hypertension dramatically increases your risk to not only develop coronary artery disease but also heart failure, peripheral vascular disease and stroke.”

Talk to your doctor if you’re concerned about your blood pressure. If you need a doctor, find one near you.