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Hypertension/High Blood Pressure Health Center

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High Blood Pressure - Topic Overview


What is high blood pressure?

Blood pressure is a measure of how hard the blood pushes against the walls of your arteries as it moves through your body. It's normal for blood pressure to go up and down throughout the day, but if it stays up, you have high blood pressure. Another name for high blood pressure is hypertension.

When blood pressure is high, it starts to damage the blood vessels, heart, and kidneys. This can lead to heart attack, stroke, and other problems. High blood pressure is called a "silent killer,'' because it doesn't usually cause symptoms while it is causing this damage.

Your blood pressure consists of two numbers: systolic and diastolic. Someone with a systolic pressure of 120 and a diastolic pressure of 80 has a blood pressure of 120/80, or "120 over 80." Blood pressure is measured in millimeters of mercury (mm Hg).

  • The systolic number shows how hard the blood pushes when the heart is pumping.
  • The diastolic number shows how hard the blood pushes between heartbeats, when the heart is relaxed and filling with blood.

An ideal blood pressure for an adult is less than 120/80. High blood pressure is 140/90 or higher. Many people fall into the category in between, called prehypertension. People with prehypertension need to make lifestyle changes to bring the blood pressure down and help prevent or delay high blood pressure.

About 1 out of 3 adults in the United States has high blood pressure.1

What causes high blood pressure?

In most cases, doctors can't point to the exact cause. But several things are known to raise blood pressure, including being very overweight, drinking too much alcohol, having a family history of high blood pressure, eating too much salt, and getting older.

Your blood pressure may also rise if you are not very active, you don't eat enough potassium and calcium, or you have a condition called insulin resistance.

What are the symptoms?

High blood pressure doesn't usually cause symptoms. Most people don't know they have it until they go to the doctor for some other reason.

Very high blood pressure can cause severe headaches and vision problems. These symptoms can also be caused by dangerously high blood pressure called malignant high blood pressure. It may also be called a hypertensive crisis or hypertensive emergency. Malignant high blood pressure is a medical emergency.

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