Measuring Blood Pressure
The only way to tell if you have high blood pressure is to have it checked. Checking your blood pressure is easy, quick and painless. Your blood pressure will be measured when you visit your health care provider, but you can also check your own blood pressure at home, or at a local pharmacy or grocery store.
By your health care professional
To measure your blood pressure, the health care provider wraps a special cuff around your arm. Cuffs come in different sizes and it will be important that the proper cuff size be used. The cuff is connected to a gauge that will measure your blood pressure. The cuff will be inflated to squeeze your arm, and then the air will slowly be released. The doctor or nurse will listen to your pulse with a stethoscope and watch the blood pressure gauge. This gauge uses a scale called “millimeters of mercury” (mmHg) to measure the pressure in your blood vessels. Alternatively, an automated or digital device may be used.
Your provider will report your blood pressure as the systolic pressure over the diastolic pressure. Discuss with your provider what your target blood pressure level is.
Your blood pressure can be affected by simple things like talking during the measurement or crossing your legs while the measurement is being taken. Before your blood pressure is measured in the office:
- Do not eat, smoke, or exercise for at least 30 minutes; do not use any medicine that can raise blood pressure (i.e. nasal sprays).
- Rest at least 5 minutes before your blood pressure is measured. Sit in a comfortable, relaxed position with both feet on the floor. Do not move or talk while the blood pressure is being measured.
- Use the bathroom if you need to before getting your blood pressure checked.
Remember that your blood pressure changes throughout the day. Blood pressure is usually highest in the morning when you wake up and move around. Blood pressure usually decreases throughout the day, and is typically lowest in the evening. Blood pressure measurements may differ by as much as 10 to 20 mmHg between your right and left arm. Your health care provider will decide which arm to use for blood pressure measurements if that is the case.
Electronic devices are used more frequently to measure blood pressure in the office. There are specialized electronic devices that perform automated office blood pressure monitoring (AOBP). With AOBP, multiple blood pressure readings are recorded using a fully automated monitor while you are resting quietly and alone. Usually three measurements are taken and the results are averaged. All the conditions noted above, in addition to proper cuff size and placement, are still necessary to ensure accurate readings with electronic devices.
At your local pharmacy
Public blood pressure machines, such as those found in pharmacies, may provide helpful information about your blood pressure, but they may also have some limitations. The accuracy of these machines depends upon several factors, such as a correct cuff size and proper use of the machines. Ask your health care provider for advice on using public blood pressure machines.
How do you choose a home blood pressure monitoring device?
If you are buying your own blood pressure monitor to use at home, there are a few points to consider.
- Finger cuffs on blood pressure monitors are less accurate and are not recommended. For most patients, arm cuffs are most accurate, but wrist cuffs are a good choice if you cannot find a cuff to fit your upper arm.
- Monitors are available with larger displays that are easier to read.
- Always purchase a monitor that has the correct cuff size for your upper arm. Most cuffs have lines showing whether they are of the proper length when wrapped around the arm.
The recommended cuff size for accurate measurement of blood pressure is shown in the table below.
|Arm Circumference||Recommended Cuff Size|
|22-26 cm||12 x 22 cm (small adult size)|
|27-34 cm||16 x 30 cm (regular adult size)|
|35-44 cm||16 x 36 cm (large adult size)|
Ask your health care provider to measure your arm circumference.
The following devices are highly recommended by Consumer Reports and have been certified (confirmed to be accurate) by respected organizations. Bring your blood pressure monitor to your doctor’s office so it can be checked for accuracy.
|Standard arm cuff||Omron 3 series
Model # BP710N
|Fancy arm cuff||Omron 10 series wireless
|Wrist cuff||Omron 3 series
Model # BP629
Target (7 series only): $48.49
Please note that the information in the table above, including pricing, is accurate as of April 2018.
How do I make sure I am measuring my blood pressure accurately?
Follow these steps to make sure that you are measuring your blood pressure accurately.
Before you take your blood pressure:
- Do not measure your blood pressure within 30 minutes of smoking, drinking alcohol, eating, or vigorous exercise. Do not take decongestants for 30 minutes before you take your blood pressure.
- Sit comfortably in a chair with your arm resting on a counter top or table at about the level of your heart.
- Sit with your back supported while keeping your feet flat on the floor.
- Use the bathroom if you need to before taking your blood pressure
- Remove clothing from the arm before applying the cuff.
- Rest for 5 minutes
When you are ready to take your blood pressure:
- Continue to sit with your back supported, your legs uncrossed, and your feet flat on the floor.
- Follow the instructions for your device. Put the cuff on by wrapping it around your bare arm above your elbow. Face the palm of your hand up to relax your arm muscles.
- Rest your arm on a table or another flat surface at the level of your heart. Keep it stretched out and relaxed. Sit still.
- Do not talk while taking your blood pressure.
- Following the directions of the monitor you are using, press the button to start the machine. The cuff will inflate and slowly deflate by itself.
Recording your blood pressure:
- The machine will display two numbers. Write down both numbers, and the data and time of the measurement if the machine does not store that information automatically. If there is a pulse recorded on the display, write that down too. Record every measurement (even if you think it is incorrect!).
- Wait one minute and then repeat the steps. You should always check at least two measurements one minute apart and write them down. This is one set of blood pressure readings.
- Make one set of blood pressure readings in the morning before taking your medications and another in the late afternoon before supper. Do this one or more days each week and then every day during the week prior to your next visit to your health care provider.
Remember to bring your record of blood pressure readings and your monitor to your clinic appointment. Your health care provider may periodically check the accuracy of your home blood pressure device.
You may record your home blood pressure readings on the charts that can be downloaded from this site. You may not need to use it if your blood pressure device is able to store your readings, and you are able to share those readings with your health care provider.
Ambulatory blood pressure monitoring
Your health care provider may decide to have you undergo Ambulatory Blood Pressure Monitoring (ABPM). ABPM may be done to get a more accurate measurement of your average blood pressure, or because you have different readings in the doctor’s office than at home, or for other reasons. This test has been available for years, and many thousands of patients have undergone ABPM without difficulty. You will wear a portable blood pressure monitor on your arm that will measure your blood pressure frequently over 24 hours (during the daytime and while you are asleep at night). From the information obtained and stored in the recorder, a report will be produced. Your health care provider will use this report to help manage your blood pressure.