Blood pressure measurement

Blood pressure is the pressure of the blood in the arteries as it is pumped around the body by the heart. Blood pressure does not stay the same all the time. It changes to meet your body’s needs. It is affected by various factors including body position, breathing or emotional state, exercise and sleep. 

To take a blood pressure reading, you need to be relaxed and comfortably seated, with your arm well supported. Alternatively, you can lie on an examination couch.

To measure your blood pressure at home, you can use either an aneroid monitor or a digital monitor. Choose the type of monitor that best suits your needs.

The aneroid monitor

The aneroid monitor has a gauge that is read by looking at a pointer on a dial. The cuff is placed around your upper arm and inflated by hand, by squeezing a rubber bulb.

One advantage of the aneroid monitor is that it can easily be carried from one place to another. Also, the cuff for the device has a built-in stethoscope, so you don't need to buy a separate stethoscope. It's also easier to manage this way. The unit may have a special feature that makes it easy to put the cuff on with one hand. In addition, the aneroid monitor usually costs less than digital monitors.

The aneroid monitor also has some disadvantages. First, it is a complicated device that can easily be damaged and become less accurate. The device is also difficult to use if it doesn't have the special feature--a metal ring--that makes it easier to put the cuff on. In addition, the rubber bulb that inflates the cuff may be difficult to squeeze. This type of monitor may not be appropriate for hearing-impaired people, because of the need to listen to heart sounds through the stethoscope.

1. Put the stethoscope ear pieces into your ears, with the ear pieces facing forward.
2. Place the stethoscope disk on the inner side of the crease of your elbow.
3. Rapidly inflate the cuff by squeezing the rubber bulb to 30 to 40 points higher than your last systolic reading. Inflate the cuff rapidly, not just a little at a time. Inflating the cuff too slowly will cause a false reading.
4. Slightly loosen the valve and slowly let some air out of the cuff. Deflate the cuff by 2 to 3 millimeters per second. If you loosen the valve too much, you won't be able to determine your blood pressure.
5. As you let the air out of the cuff, you will begin to hear your heartbeat. Listen carefully for the first sound. Check the blood pressure reading by looking at the pointer on the dial. This number will be your systolic pressure.
6. Continue to deflate the cuff. Listen to your heartbeat. You will hear your heartbeat stop at some point. Check the reading on the dial. This number is your diastolic pressure.
7. Write down your blood pressure, with the systolic pressure before the diastolic pressure (for example, 120/80).
8. If you want to repeat the measurement, wait 2 to 3 minutes before reinflating the cuff.

The digital monitor

Digital monitors have either manual or automatic cuffs. The blood pressure reading flashes on a small screen.

Because the digital monitor is automatic, it is the more popular blood-pressure measuring device. The blood pressure measurement is easy to read, because the numbers are shown on a screen. Some electronic monitors also have a paper printout that gives you a record of the blood pressure reading.

The digital monitor is easier to use than the aneroid unit. It has a gauge and stethoscope in one unit, and the numbers are easy to read. It also has an error indicator, and deflation is automatic. Inflation of the cuff is either automatic or manual, depending on the model. This blood pressure monitoring device is good for hearing-impaired patients, since there is no need to listen to heart sounds through the stethoscope.

A disadvantage of the digital monitor is that the accuracy is changed by body movements or an irregular heart rate. In addition, the monitor requires batteries. Some models are designed for use with the left arm only. This may make them hard for some patients to use.

1. Put the cuff around the arm. Turn the power on, and start the machine.
2. The cuff will inflate by itself with a push of a button on the automatic models. On the semiautomatic models, the cuff is inflated by squeezing the rubber bulb. After the cuff is inflated, the automatic mechanism will slowly reduce the cuff pressure.
3. Look at the display window to see your blood pressure reading. The machine will show your systolic and diastolic blood pressures on the screen. Write down your blood pressure, with the systolic pressure before the diastolic pressure (for example, 120/80).
4. Press the exhaust button to release all of the air from the cuff.
5. If you want to repeat the measurement, wait 2 to 3 minutes before reinflating the cuff.

If your blood pressure remains high, it can lead to serious problems like heart attack, stroke, heart failure or kidney disease. The medical name for persistently high blood pressure is ‘hypertension’. There is no ‘ideal’ blood pressure reading. The following classification for clinic blood pressures in adults can be used as a guide:

• Normal blood pressure – generally less than 120/80
• High–normal (the higher range of normal) – between 120/80 and 139/89
• Mild high blood pressure – between 140/90 and 159/99
• Moderate high blood pressure – between 160/100 and 179/109
• Severe high blood pressure – equal to or more than 180/110.

High blood pressure usually does not give warning signs. You can have high blood pressure and feel perfectly well. The only way to find out if your blood pressure is high is to have it checked regularly by your doctor.

If your blood pressure is ‘normal’ and you have no other risk factors for cardiovascular disease, and no personal or family history of high blood pressure, a check every two years and during routine visits to your doctor is recommended.

If your blood pressure is ‘high–normal’ (or higher), or if you have other risk factors for cardiovascular disease, a personal or family history of high blood pressure, stroke or heart attack, it is best to have it checked more frequently. Ask your doctor for advice.

If blood pressure remains high, it can lead to serious health problems. You will be more at risk of these problems if you smoke, are overweight, are physically inactive, have diabetes, have high blood cholesterol, are socially isolated or have depression.
Lifestyle changes are very important to help to control high blood pressure and lower your risk of cardiovascular disease. Suggestions include:

• Reduce your excess body weight
• Be physically active
• Limit your alcohol intake
• Quit smoking
• Decrease your salt/sodium intake
• Increase your potassium intake through eating a wide variety of fruit, vegetables, plain unsalted nuts and legumes.

Healthy eating is important in controlling high blood pressure and reducing your risk of heart disease. Enjoying a variety of foods from the different food groups is the key to healthy eating. Reducing salt intake can also help to control high blood pressure or avoid high blood pressure altogether. 

There is a large variety of medicines available to lower and control high blood pressure. Your doctor might call them ‘antihypertensives’. These medicines do not cure high blood pressure, but they do control it. Once you start to take medicines to control your blood pressure, you will probably need to take them for the rest of your life. However, the dose of these medicines may change over time. If you need to take medicine, your doctor will advise you on the correct type of medicine and the dose. Two or more different medicines are often needed to get good control of blood pressure.