Home Blood Pressure Test

	Test Overview
	Health Tools
	Why It Is Done
	How To Prepare
	How It Is Done
	How It Feels
	Risks
	Results
	What Affects the Test
	What To Think About
	References
	Credits

A home blood pressure test allows you to keep track of your blood pressure at home. Blood pressure is a measure of the force of blood inside an artery. A blood pressure measurement is taken by temporarily stopping the flow of blood in an artery (usually by inflating a cuff around the upper arm) and then listening for the sound of the blood beginning to flow through the artery again as air is released from the cuff.

As blood flows through the artery, it can be heard through a stethoscope placed on the skin over the artery. Blood pressure is recorded as two measurements.

• The reading on the gauge when blood flow is first heard is called the systolic pressure. Systolic pressure represents the peak blood pressure that occurs when the heart contracts.
• The reading on the gauge when blood flow can no longer be heard is the diastolic pressure. Diastolic pressure represents the lowest blood pressure that occurs when the heart relaxes between beats.

These two pressures are expressed in millimeters of mercury (mm Hg) because the original devices that measured blood pressure used a column of mercury. Blood pressure measurements are recorded as systolic/diastolic (say "systolic over diastolic"). For example, if your systolic pressure is 120 mm Hg and your diastolic pressure is 80 mm Hg, your blood pressure is recorded as 120/80 (say "120 over 80").

Types of blood pressure monitors

The two general types of blood pressure monitors commonly available are manual and automatic.

Manual blood pressure monitors

Manual models are similar to those that your doctor might use to take your blood pressure. Called a sphygmomanometer, these devices usually include an arm cuff, a squeeze bulb to inflate the cuff, a stethoscope or microphone, and a gauge to measure the blood pressure.

Blood pressure is displayed on a circular dial with a needle. As the pressure in the cuff rises, the needle moves clockwise on the dial. As the cuff pressure falls, the needle moves counterclockwise.

Automatic (also called electronic or digital) blood pressure monitors

Electronic battery-operated monitors use a microphone to detect blood pulsing in the artery. You do not need to listen with a stethoscope. The cuff, which is attached to your wrist or upper arm, is connected to an electronic monitor that automatically inflates and deflates the cuff when you press the start button.

The type of blood pressure monitor typically found in supermarkets, pharmacies, and shopping malls is an electronic device.

Ambulatory blood pressure monitoring (ABPM)

Ambulatory blood pressure monitoring (ABPM) is another method that may be ordered by your doctor if other methods do not give consistent results. It is often used if there is a big difference between the blood pressure readings you get at home and your readings in your doctor's office. You will wear a cuff on one arm and a monitor around your waist. Your doctor's office will fit you with the device and tell you how to use it.

Health tools help you make wise health decisions or take action to improve your health.

	Actionsets are designed to help people take an active role in managing a health condition.
	High blood pressure: Checking your blood pressure at home

Home blood pressure monitoring measures your blood pressure at different times and in different places (such as at home and at work) during the day. It may be done to:

• Find out if you have high blood pressure.
• Keep track of how well medicine taken to reduce blood pressure is working.
• Check how lifestyle changes, such as weight loss and exercise, are affecting blood pressure. Home monitoring can help people feel more involved in and more in control of their own health care.
• Watch for changes in blood pressure that may be side effects of medicines.
• Check for problems with high blood pressure during pregnancy or with preeclampsia. For more information, see the topic Preeclampsia and High Blood Pressure During Pregnancy.

Ambulatory blood pressure monitoring (ABPM) is often used if there is a big difference between the blood pressure readings you get at home and your readings in your doctor's office.

Avoid caffeine, tobacco, or medicines known to raise blood pressure (such as nasal decongestant sprays) for at least 30 minutes before taking your blood pressure. Do not exercise for at least 30 minutes before taking your blood pressure.

Take your blood pressure while you feel comfortable and relaxed. Sit quietly with both feet on the floor for at least 5 minutes before you take your blood pressure.

Specific instructions

When you first get a blood pressure monitor, take it to your doctor's office to make sure it is working right. Have your health professional take your blood pressure and then compare that result with your own device. Ask your health professional to watch you use your monitor to make sure that you are using it correctly. It is a good idea to have your monitor checked every year.

The size of the blood pressure cuff and where you place the cuff on your arm can change your blood pressure readings. If the cuff is too small or too large, the measurements will not be accurate. The inflatable part of the cuff needs to wrap around at least 80% of your arm. Hospital and medical supply stores generally carry many cuff sizes and can help make sure that your cuff fits you. See a picture of a cuff with the proper fit.

Your blood pressure in your right arm may be higher or lower than the blood pressure in your left arm. For this reason, try to use the same arm for every reading. Blood pressure readings also rise and fall at different times during the day. They are usually highest in the morning and lowest in the evening. Ask your doctor if you should take your blood pressure at the same time of day each time you take it, or if you should take your blood pressure at different times of the day.

The instructions for using blood pressure monitors vary depending upon the type of blood pressure monitor you choose. Here are some general guidelines:

• Take your blood pressure while you feel comfortable and relaxed. Sit quietly for at least 5 minutes with both feet on the floor. Try not to move or talk while you are measuring your blood pressure.
• Sit with your arm slightly bent and resting comfortably on a table so that your upper arm is on the same level as your heart.
• Place the blood pressure cuff on the skin of your upper arm. You may have to roll up your sleeve, remove your arm from the sleeve, or take your shirt off.

Manual blood pressure monitors

Sit with your arm slightly bent and resting comfortably on a table so that your upper arm is on the same level as your heart. Expose your upper arm by rolling up your sleeve but not so tightly as to constrict blood flow. If you are not able to roll up your sleeve, remove your arm from the sleeve or take off your shirt. Wrap the blood pressure cuff snugly around your upper arm so that the lower edge of the cuff is about 1 in. (2.5 cm) above the bend of your elbow. A large artery (called the brachial artery) is located slightly above the inside of your elbow. You can check its location by feeling for a pulse in the artery with the fingers of your other hand.

If you are using a stethoscope, place the earpieces in your ears and the bell of the stethoscope over the artery, just below the cuff. The stethoscope should not rub on the cuff or your clothing, since this may cause noises that can make your pulse hard to hear. If you are using a cuff with a built-in stethoscope bell, be sure the part of the cuff with the stethoscope is positioned just over the artery. The accuracy of a blood pressure recording depends on the correct positioning of the stethoscope over the artery. You may want to have another person who can use a stethoscope properly help you take your blood pressure.

Close the valve on the rubber inflating bulb. Squeeze the bulb rapidly with your opposite hand to inflate the cuff until the dial or column of mercury reads about 30 mm Hg higher than your usual systolic pressure. (If you don't know your usual pressure, inflate the cuff to 210 mm Hg or until the pulse at your wrist disappears.) The pressure in the cuff will stop all blood flow within the artery temporarily.

Now open the pressure valve just slightly by twisting or pressing the valve on the bulb. The pressure should fall slowly at about 2 to 3 mm Hg per second. Some blood pressure devices have a valve that automatically controls this rate. As you watch the pressure slowly fall, note the level on the dial at which you first start to hear a pulsing or tapping sound through the stethoscope. The sound is caused by the blood starting to move through the closed artery. This is your systolic blood pressure. If you have trouble hearing the start of your pulse through the stethoscope, you can check your systolic blood pressure by noting the level on the dial when you are able to feel the pulse at your wrist once again.

Continue letting the air out slowly. The sounds will become muffled and will finally disappear. Note the pressure when the sounds completely disappear. This is your diastolic blood pressure. Finally, let out all the remaining air to relieve the pressure on your arm.

Be sure to write your numbers in your log book, along with the date and time.

Electronic blood pressure monitors

For electronic models, press the on/off button on the electronic monitor and wait until the ready-to-measure "heart" symbol appears next to zero in the display window. Then press the start button. The cuff will inflate automatically to approximately 180 mm Hg (unless the monitor determines that you require a higher value). It then begins to deflate automatically, and the numbers on the screen will begin to drop. When the measurement is complete, the heart symbol stops flashing and your blood pressure and pulse readings are displayed alternately.

All blood pressure monitors

At first it is a good idea to take your blood pressure 3 times in a row, 5 or 10 minutes apart. As you get more comfortable taking your own blood pressure, you will only need to measure it once or twice each time.

Check your blood pressure cuff frequently to see that the rubber tubing, bulb, valves, and cuff are in good condition. Even a small hole or crack in the tubing can lead to inaccurate results.

To help develop your skills, see:

High blood pressure: Checking your blood pressure at home.

You may feel some discomfort when the blood pressure cuff inflates, squeezing your arm.

There are no risks or complications from this test.

A home blood pressure test allows you to keep track of your blood pressure at home.

Blood pressure readings of less than 90/60 mm Hg are normal as long as you feel well. Generally, the lower your blood pressure, the better. However, if you have low blood pressure and feel lightheaded, faint, or like you may vomit, talk to your doctor.

Reasons you may not be able to have the test or why the results may not be helpful include:

• You have poor hearing or eyesight. An electronic arm- or wrist-cuff model may be a better choice for you.
• You cannot put the cuff on or twist the dial to inflate the cuff.
• The cuff is either too large or too small for your arm.

Blood pressure normally goes up and down from day to day and even from minute to minute, depending upon how active you are, whether you are standing up or sitting down, and what medicines you are taking. Other things that can change blood pressure include being too hot or too cold, whether you have recently eaten, and whether you are relaxed or feeling stressed.

Home blood pressure monitoring works best when you also record your daily activities, such as the time you take medicine if you feel upset or stressed, in a diary. This can help explain changes in your blood pressure readings and help your doctor adjust your medicines.

Your blood pressure may only be high when you go to your doctor's office. This is called white-coat (or office) hypertension and may be caused by stress about seeing your doctor. When you regularly check your blood pressure at home, you may find that your blood pressure is lower when you are not at the doctor's office.

• Home blood pressure monitors should be checked regularly to make sure they are working right. You may wish to take your monitor to your doctor's office or health department to compare blood pressure readings. This is also a good time to have a health professional watch you take your blood pressure to make sure that you are doing it correctly.
• Your blood pressure may go up and down from day to day and from moment to moment. Blood pressure tends to be higher in the morning and lower at night. Stress, smoking, eating, exercise, cold, pain, noise, medicines, and even talking can affect it. A single high reading does not mean you have high blood pressure (hypertension), and a single normal reading does not necessarily mean you do not have high blood pressure. The average of several repeated measurements throughout the day is more accurate than a single reading.
• Do not adjust your blood pressure medicines based on home blood pressure readings unless your doctor tells you to.
• Talk to your doctor about how often you should monitor your blood pressure. Early detection and treatment with a combination of medicine and lifestyle changes (weight loss, diet, exercise, stress reduction) may reduce the health risks caused by high blood pressure. If you are being treated for high blood pressure, you may only need to check your blood pressure once a week or less often. You may want to check your blood pressure more often if your blood pressure is not well-controlled or if you are taking different medicines or changing doses of a medicine.
• Most people will have some difference in the blood pressure between the right and the left arm. However, if you have a large difference (greater than 20 mm Hg), talk to your doctor about what this may mean.
• Some types of blood pressure monitors can store the results of your test and transfer this information to your computer. Some can relay these readings over a phone line to your doctor's office.
• Blood pressure monitors that measure your blood pressure in your finger or your wrist are not usually accurate and are not recommended.

Citations

1. Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (2003). Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure JNC Express (NIH Publication No. 03–5233). Bethesda, MD: U.S. Department of Health and Human Services.