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Measuring Blood Pressure

What is a blood pressure measurement?

Each time your heart beats, it pumps blood into your arteries. A blood pressure measurement is a test that measures the force (pressure) in your arteries as your heart pumps. Blood pressure is measured as two numbers:

  • Systolic blood pressure (the first and higher number) measures pressure inside your arteries when the heart beats.
  • Diastolic blood pressure (the second and lower number) measures the pressure inside the artery when the heart rests between beats.

High blood pressure, also known as hypertension, affects tens of millions of adults in the United States. It increases the risk of life-threatening conditions including heart attack and stroke. But high blood pressure rarely causes symptoms. A blood pressure measurement helps diagnose high blood pressure early, so it may be treated before it leads to serious complications.

Other names: blood pressure reading, blood pressure test, blood pressure screening, sphygmomanometry

What is it used for?

A blood pressure measurement is most often used to diagnose high blood pressure.

Blood pressure that's too low, known as hypotension, is much less common. But you may get tested for low blood pressure if you have certain symptoms. Unlike high blood pressure, low blood pressure usually causes symptoms. These include:

  • Dizziness or lightheadedness
  • Nausea
  • Cold, sweaty skin
  • Pale skin
  • Fainting
  • Weakness

Why do I need a blood pressure test?

A blood pressure measurement is often included as part of a regular checkup. Adults 18 years and older should have their blood pressure measured at least once every two to five years. You should get tested every year if you have certain risk factors. You may be at higher risk if you:

  • Are 40 years old or older
  • Are overweight or have obesity
  • Have a family history of heart disease or diabetes
  • Take birth control pills
  • Are Black/African American. Black/African Americans have a higher rate of high blood pressure than other racial and ethnic groups

You may need this test if you have symptoms of low blood pressure.

What happens during a blood pressure test?

A blood pressure test includes the following steps:

  • You will sit in a chair with your feet flat on the floor.
  • You will rest your arm on a table or other surface, so your arm is level with your heart. You may be asked to roll up your sleeve.
  • Your provider will wrap a blood pressure cuff around your arm. A blood pressure cuff is a strap-like device. It should fit snugly around your upper arm, with the bottom edge placed just above your elbow.
  • Your provider will inflate the blood pressure cuff using a small hand pump or by pressing a button on an automated device.
  • Your provider will measure the pressure manually (by hand) or with an automated device.
    • If manually, he or she will place a stethoscope over the major artery in your upper arm to listen to the blood flow and pulse as the cuff inflates and deflates.
    • If using an automated device, the blood pressure cuff automatically inflates, deflates, and measures pressure.
  • As the blood pressure cuff inflates, you'll feel it tighten around your arm.
  • Your provider will then open a valve on the cuff to slowly release air from it. As the cuff deflates, blood pressure will fall.
  • As the pressure falls, a measurement is taken when the sound of blood pulsing is first heard. This is the systolic pressure.
  • As the air continues to be let out, the blood pulsing sound will start to go away. When it completely stops, another measurement is taken. This is the diastolic pressure.

This test only takes about one minute to complete.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a blood pressure measurement.

Are there any risks to the test?

You may have a little discomfort when the blood pressure cuff inflates and squeezes your arm. But this feeling only lasts for a few seconds.

What do the results mean?

Your results, also known as a blood pressure reading, will contain two numbers. The top or first number is the systolic pressure. The bottom or second number is the diastolic pressure. High blood pressure readings are also labeled by categories, ranging from normal to crisis. Your reading may show your blood pressure is:

Blood Pressure Category Systolic Blood Pressure
Diastolic Blood Pressure
Normal Less than 120 and Less than 80
High Blood Pressure (no other heart risk factors) 140 or higher or 90 or higher
High Blood Pressure (with other heart risk factors, according to some providers) 130 or higher or 80 or higher
Dangerously high blood pressure - seek medical care right away 180 or higher and 120 or higher

If you've been diagnosed with high blood pressure, your provider may recommend lifestyle changes and/or medicines to control your blood pressure. Your provider may also recommend that you regularly check your blood pressure at home with an automated blood pressure monitor. An at-home blood pressure monitor usually includes a blood pressure cuff and a digital device to record and display blood pressure readings.

Home monitoring is not a replacement for regular visits to your provider. But it can provide important information, such as whether treatment is working or your condition may have worsened. Also, home monitoring may make the test less stressful. Many people get nervous about getting their blood pressure taken at a provider's office. This is called "white coat syndrome." It can cause a temporary rise in blood pressure, making the results less accurate. For more information about home monitoring of blood pressure, talk to your provider.

If you were tested for low blood pressure, a blood pressure reading of 90 systolic, 60 diastolic (90/60) or lower is considered abnormal. Treatments for low blood pressure may include medicines and making certain changes to your diet.

Is there anything else I need to know about a blood pressure measurement?

If you were diagnosed with high blood pressure, your provider may recommend one or more of the following lifestyle changes.

  • Exercise regularly. Staying active can help lower your blood pressure and also help manage your weight. Most adults should aim for 150 minutes of physical activity per week. Check with your provider before beginning an exercise program.
  • Keep a healthy weight. If you are overweight, losing as little as 5 pounds can lower your blood pressure.
  • Eat a healthy diet that includes fruits, vegetable, and whole grains. Limit foods high in saturated fat and total fat.
  • Reduce salt in your diet. Most adults should have less than 1500 mg of salt per day.
  • Limit alcohol use. If you choose to drink, limit yourself to one drink a day if you are a woman; two drinks a day if you're a man.
  • Don't smoke.


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The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.