What is high blood pressure?

High blood pressure is also known as hypertension

When blood pressure is high, blood vessels and organs such as the heart, kidney and brain, are persistently under increased pressure. As a result, high blood pressure can increase the risk of cardiovascular disease and stroke. High blood pressure needs to be diagnosed, so it can be managed properly.

What is blood pressure

The heart is a very important organ that is responsible for ensuring that blood is moved around the body. Thanks to the heart, oxygen and nutrients are delivered to every tissue and organ in your body. In order to make this delivery possible, the heart has to generate a force to pump blood around your body. The force the heart generates to make blood run through your arteries is called blood pressure.

A person’s blood pressure is typically expressed as two numbers:

SYSTOLIC

Blood pressure (mm Hg)

The highest level of blood pressure,

when blood is pumped from the

heart to the entire body.

DIASTOLIC

Blood pressure (mm Hg)

The lowest level of blood pressure,

when your heart is relaxed before it

contracts again.

The ideal blood pressure for an healthy adult is <120/80 mm Hg¹.

How to measure blood pressure ?

Most of the time, it is your doctor or a nurse who will measure your blood pressure, for example, during a routine visit. To do so, they will use a sphygmomanometer. It is a pressure-measuring device (manometer) connected to an inflatable cuff that is wrapped around your upper arm. The doctor will inflate the cuff, and you will feel your arm being squeezed quite hard. The air in the cuff is then let out slowly, and you will feel the grip of the cuff lessen. Blood pressure can then be measured with the manometer (in millimeters of mercury [mm Hg]).

Two different sphygmomanometers exist:

A MANUAL ONE

The doctor or nurse inflates the cuff using a hand pump and then uses a stethoscope to listen to your pulse.

A DIGITAL ONE

The cuff inflates and deflates automatically. The pulse is detected by a sensor inside the device.

To get an accurate measurement of your blood pressure, when a measurement is taken you should have rested for at least five minutes previously and be seated and silent, ie, not talking.

What is high blood pressure ?

Blood pressure can be high, normal, or low, but over time and with age, blood pressure rises. Why? The walls of large arteries become more rigid and the small blood vessels become narrower. Because of these changes, the heart has to generate a greater force to keep blood flowing around the body. This leads to an increase in blood pressure. Hypertension is defined as blood pressure that is consistently higher than 140/90 mm Hg¹.

What do my numbers mean?

Optimal

Systolic < 120 and Diastolic < 80

Normal

Systolic 120-129 and/or Diastolic 80-84

“It’s OK, keep going!”

High normal

Systolic 130-139 and/or Diastolic 85-89

“Your blood pressure needs to be checked more often and you should follow lifestyle advice”

What are the causes of high blood pressure ?

There are two types of hypertension: primary (or essential hypertension) and secondary hypertension.

Primary hypertension describes high blood pressure that has no obvious cause. There are a number of factors that can increase the risk of developing high blood pressure:

Lack of physical activity

Stress

Excess weight

Excessive alcohol intake

Excessive salt intake

Chronic heavy smoking

Caffeine

Sugar

Secondary hypertension concerns high blood pressure produced by identifiable causes (for example, an abnormal production of hormones from the adrenal glands). Only a small number of patients suffer from this kind of hypertension. Once the cause is found and treated correctly, blood pressure should return to normal.

National Heart Foundation of Australia. Guideline for the diagnosis and management of hypertension in adults 2016