Measuring your blood pressure is an important part of assessing cardiovascular health because raised blood pressure (hypertension) is a very common cause of cardiovascular disease.

It is estimated that one in three people in the UK suffer from hypertension, so this is a common problem. It is important to note that high blood pressure can only be diagnosed by measuring it, since most people have no symptoms at all, even when their blood pressure is very high. Along with high cholesterol, hypertension is an easily treatable risk factor for cardiovascular disease, so blood pressure measurement is one of the simplest and most effective tests that we have in terms of disease prevention.

At The London Clinic, we have several different ways of measuring blood pressure, each of which is used in different circumstances.

What is blood pressure?

When your heart beats, it pumps blood that contains oxygen around your body so that your cells can function. As the blood is pumped through your arteries, it pushes against the vessel walls, which are muscular and flexible. The degree to which your blood pushes against the artery walls is known as your blood pressure. The more forcefully the blood is pumped, the more the artery walls are stretched and the higher your blood pressure will be.

How is blood pressure measured?

Blood pressure is written as two numbers that are recorded in millimetres of mercury (mmHg), for example, 120/80 mmHg. The first number measures the maximum (systolic) pressure of your arteries at the moment when your heart beats, while the second number measures the lowest (diastolic) pressure of your arteries between heartbeats when your heart is resting.

High blood pressure vs. low blood pressure

If your systolic or diastolic number is higher than normal, this means that you have high blood pressure. Having high blood pressure means that your heart has to work harder to pump blood, and your arteries are stretched more than normal, which can result in things like a heart attack or stroke. High blood pressure usually doesn’t come with any associated symptoms, and so the only way to see if it’s too high is to measure it. Low blood pressure is not considered dangerous unless you start to experience symptoms such as dizziness, fainting, dehydration, a loss of concentration, blurred vision or rapid breathing.

How is blood pressure measured?

Your blood pressure is measured using a device called a sphygmomanometer. This device contains an inflatable cuff, a rubber bulb, and a measuring dial. First, your doctor or nurse will secure the cuff to your upper arm and place a stethoscope on the arteries inside your elbow. Next, he or she will pump the bulb attached to the cuff so that it inflates and constricts around your arm. At this point, the cuff will be released, and as your doctor hears the sound of blood flowing back down your arm through the stethoscope, they will take a reading of your systolic pressure from the measuring dial. Once this rushing sound has subsided, your doctor will record your diastolic pressure from the dial.

Different types of blood pressure monitors

Besides using a cuff as described above, there are several other ways to measure your blood pressure:

  • Ambulatory 24-hour blood pressure monitoring: this takes measurements of your blood pressure for 24 hours as you go about your normal daily activities. You’ll wear a device that will record your blood pressure at regular intervals over 24 hours, which allows your doctor to get a good overall picture of your blood pressure and how it varies over time.
  • Digital sphygmomanometers: these are electronic measuring devices that take an electronic reading of your blood pressure instead of using a manual pump system.
  • Portable blood pressure monitors: these are small devices that are powered by batteries. The strap fits around your wrist, and you press a button to get a digital reading on a small screen attached to the strap.