What Is High Blood Pressure?

Odds are that someone either to the left or right of you has high blood pressure. Nearly one in three adults in the U.S. has high blood pressure (also called hypertension), and many may go for years without knowing they have the disease because often it has no signs or symptoms.

It is crucial to know what high blood pressure is and how it affects your body so you have the power to measure your blood pressure, monitor for changes, and maintain control.

What Is High Blood Pressure?

At its simplest, blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps blood. If this pressure rises and stays high over time, it can damage the body. That’s why it is important to know your blood pressure and follow your health care professional’s instructions if it is too high.

This video, from our partner Million Hearts®, shows how high blood pressure in your body is like a radiator on the fritz in your basement:

Why Does High Blood Pressure Matter?

High blood pressure is a serious condition that can lead to heart disease, heart failure, stroke, kidney failure, vision loss, and other health problems. In fact, high blood pressure puts millions of Americans at increased risk for heart disease and stroke – two of the leading causes of death in the U.S.

How Do I Know If I Have High Blood Pressure?

Your blood pressure is made up of two numbers, like a fraction. It is measured in millimeters of mercury (abbreviated as mmHg). Both numbers are important in determining whether your blood pressure is normal or high. The top number (known as systolic) represents the pressure in your blood vessels when your heart beats, while the bottom number (diastolic) represents the pressure in your vessels as your heart rests between beats.

What do these numbers mean? See the chart below to find your numbers. If your numbers fall into the “at risk” (prehypertension) or “high” classifications, or are often above 140/90, make an appointment with your health care provider.

Blood Pressure Classification

Blood Pressure Levels


Systolic (Top Number): less than 120 mmHg
Diastolic (Bottom Number): less than 80 mmHg

At Risk for High Blood Pressure (Prehypertension)

Systolic: 120-139 mmHg
Diastolic: 80-89 mmHg

High Blood Pressure

Systolic: 140 mmHg or higher
Diastolic: 90 mmHg or higher

Note: If you have diabetes or chronic kidney disease, the goal is to get and keep your blood pressure below 130/80 mmHg (130 top/systolic number, 80 bottom/diastolic number).