What is high blood pressure?
Blood pressure is the force that blood exerts against the walls of your arteries as the heart pumps it around the body. Some pressure is necessary — without it, blood wouldn't reach your organs. But when that pressure is consistently too high, it puts strain on the heart, blood vessels and other organs.
High blood pressure, known medically as hypertension, is often called a "silent condition" because it rarely causes obvious symptoms — yet over time it significantly increases the risk of heart attack, stroke, heart failure and kidney disease.
In Australia, around one in three adults has high blood pressure, and many don't know it.
How is blood pressure measured?
Blood pressure is recorded as two numbers — for example, 120/80 mmHg. The first (higher) number is systolic pressure: the pressure when the heart beats. The second is diastolic pressure: the pressure when the heart rests between beats.
A reading consistently at or above 140/90 mmHg is generally considered high. Readings between 120/80 and 140/90 are often described as "high-normal" or "elevated" — a sign worth watching and acting on.
Blood pressure can vary throughout the day depending on activity, stress and other factors, so diagnosis is usually based on multiple readings over time.
What causes high blood pressure?
For most people, there's no single identifiable cause — this is called primary (or essential) hypertension, and it develops gradually over time as a result of a combination of genetic and lifestyle factors.
Key lifestyle contributors include eating too much salt, being physically inactive, carrying excess weight, drinking too much alcohol, smoking and chronic stress. Certain health conditions — including kidney disease, thyroid problems and sleep apnoea — can also raise blood pressure, as can some medications.
Why does it matter?
High blood pressure is one of the most significant modifiable risk factors for cardiovascular disease. It forces the heart to work harder with every beat, gradually thickening and stiffening the heart muscle. It damages the inner lining of arteries, accelerating the build-up of fatty plaque that leads to heart attack and stroke. It strains the kidneys and can impair their ability to filter blood over time.
The insidious thing about hypertension is that all of this can be happening without any warning signs. Many people discover their blood pressure is high only when they have a routine check or after an event like a heart attack or stroke.
How is high blood pressure treated?
Lifestyle changes are the first line of treatment — and for people with mildly elevated blood pressure, they can be enough. Reducing salt intake, eating more fruit, vegetables and whole grains, being physically active, limiting alcohol, not smoking and managing stress all have meaningful effects on blood pressure.
When lifestyle changes alone aren't sufficient, a range of effective medications are available — including ACE inhibitors, calcium channel blockers, diuretics and beta-blockers.
Most people with established hypertension will need medication, often for life, to keep their blood pressure in a safe range.
Regular monitoring — whether at a GP clinic or at home — is an important part of managing the condition.