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High Blood Pressure


The Manual's Editorial Staff

Last full review/revision Jan 2020| Content last modified Jan 2020
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What is high blood pressure?

Each heart beat pushes blood through your arteries. Arteries are the blood vessels that carry blood from your heart to your body. Blood pressure is the pressure of blood in your arteries. Without blood pressure, blood wouldn't flow through your blood vessels and you'd die. But blood pressure that's too high stresses your heart and damages your arteries and other organs.

  • After many years, high blood pressure causes serious problems, such as heart attack, heart failure, stroke, or kidney damage

  • High blood pressure is called the silent killer because it usually doesn't cause symptoms until it's too late

  • High blood pressure causes more deaths and serious problems than almost any other condition, but most complications can be prevented by proper treatment

  • Exercising, eating less salt, losing weight, quitting smoking, and drinking less alcohol help lower blood pressure

  • You also may need to take blood pressure pills—sometimes 2 or 3 different ones

  • It's important to keep taking your medicine even if you feel fine

How is blood pressure measured?

Doctors use a blood pressure cuff to check your blood pressure. Two numbers are recorded. For example, your blood pressure might be 120/80, called "120 over 80."

The first number is the highest pressure in the arteries, when your heart pushes the blood out. This is the systolic pressure.

The second number is the lowest pressure in the arteries, when your heart is relaxed just before it begins to push blood out. This is the diastolic pressure.

Your blood pressure isn't exactly the same every time it's measured. It varies a little throughout the day and day-to-day. But usually the reading stays within 5 or 10 points over time.

How do doctors define high blood pressure?

In adults, doctors classify blood pressure as:

  • Normal: Less than 120/80

  • Elevated: 120–129 systolic AND less than 80 diastolic

  • Stage 1 high blood pressure: 130–139 systolic OR 80-89 diastolic

  • Stage 2 high blood pressure: 140 or more systolic OR 90 or more diastolic

What causes high blood pressure?

High blood pressure usually doesn't have a clear cause—it just happens. This kind of high blood pressure often runs in families. It's more common in people over 45 and in blacks. Risk of this kind of high blood pressure is increased by:

  • Increasing age

  • Being overweight or obese

  • Not being active each day

  • Stress

  • Smoking

  • Eating too much salt

Less often, other medical problems cause high blood pressure, particularly:

  • Kidney problems

  • Hormone problems, such as too much thyroid hormone (hyperthyroidism) or too much adrenal hormones (Cushing syndrome)

  • Sometimes, being pregnant

Many drugs and substances can raise blood pressure. Blood pressure goes down when the effects of the drug or substance wears off unless you have high blood pressure for other reasons. Common substances that raise blood pressure include:

  • Alcohol

  • Birth control pills

  • Caffeine

  • Corticosteroids

  • Nasal decongestants, such as phenylephrine and pseudoephedrine

  • NSAIDs (anti-inflammatory drugs such as ibuprofen)

  • Stimulant drugs such as amphetamines and cocaine

What are the symptoms of high blood pressure?

High blood pressure usually doesn't cause symptoms. You can't tell whether your blood pressure is high based on how you feel. People often think headaches, nosebleeds, dizziness, feeling tired, and other general symptoms are due to high blood pressure. But you're just as likely to have these things when your blood pressure is normal.

However, if your high blood pressure has caused complications, such as a heart attack, heart failure, or stroke, you may have symptoms of those conditions, such as:

  • Chest pain

  • Shortness of breath

  • Headache

  • Confusion or trouble speaking

  • Blurry vision

  • Weakness or paralysis of one side of your body or face

How can doctors tell if I have high blood pressure?

Tests to check for high blood pressure

Doctors use a blood pressure cuff to check your blood pressure 3 or more times. Doctors may use a stethoscope or a machine to measure your blood pressure. Doctors can measure blood pressure in your arm or leg.

The doctor may find high blood pressure when you're nervous or not relaxed, which is a common feeling in a doctor's office. The doctor may ask you to sit for a while or come back for another reading to be sure that you're feeling calm and comfortable so that the reading is accurate. Sometimes, the doctor will have you take your own blood pressure with a home blood pressure machine for a day or two.

Tests if you have high blood pressure

If you have high blood pressure, doctors will do:

  • A physical exam

  • An eye exam

  • An ECG—test that measures your heart's electrical currents and records them on a piece of paper

  • Blood tests and urine tests

Doctors may also do other tests to figure out if there's a more unusual cause of your high blood pressure. They'll do these tests especially if you're young or if the usual treatment doesn't lower your blood pressure.

How do doctors treat high blood pressure?

High blood pressure usually can't be cured. But changing some of your behaviors and taking medicine can help you control it. The goal for your blood pressure depends on your age and what other medical problems you have.

Once treatment is started, it's important to check your blood pressure often to be sure it gets to the right level. Doctors may also ask you to check your blood pressure at home and keep a record to share at your next doctor's visit. Your doctor may need to add or change medicines to bring your blood pressure down.

Behavior changes

Everyone with high blood pressure needs to change their lifestyle. Doctors usually suggest you go on a diet called DASH (Dietary Approaches to Stop Hypertension). This diet has you eating lots of fruits and vegetables and using low-fat dairy products. You can eat poultry, fish, whole grains, and nuts, but not much red meat, sweets, and salt. Doctors may also suggest you:

  • Start exercising or exercise more often

  • Lose weight if you're overweight

  • Drink less alcohol

  • Stop smoking

  • Learn how to relax to deal with stress


Doctors often prescribe one or more blood pressure medicines. Different medicines lower blood pressure in different ways. Sometimes it takes time to find the right combination of medicines at the right doses to bring blood pressure down to your goal level.

Most people need to take medicine for the rest of their life. It's very important that you and your doctor keep checking your blood pressure to be sure that it stays down.

Always tell your doctor if your blood pressure medicine is making you not feel well. Your doctor can change the amount or type you're taking to help you feel better.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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