They don’t call high blood pressure a “silent killer” for nothing. Turns out, around a third of Australians have this condition, which, left unaddressed, can cause hardening of the arteries, stroke, kidney damage, and even early cognitive decline and dementia. Yet most people with high blood pressure (also called hypertension) have no idea they’re affected.

“High blood pressure, in most cases, is asymptomatic,” says cardiologist Dr Lawrence Phillips “So people don’t feel that they have it, which is why regular screening is so important.” (If you haven’t had your numbers checked in two years, see a doc.)

In the simplest terms, blood pressure is the force of your blood against the walls of your blood vessels and arteries, and it is expressed as two numbers: The top number (systolic blood pressure) represents the pressure or force in the arteries when your heart beats, and the bottom number (diastolic blood pressure) is the pressure measured between heart beats, explains cardiologist Dr Amnon Beniaminovitz.

Anything over 140/90 mmHg is considered high blood pressure.

While normal blood pressure is necessary for survival, high blood pressure is dangerous because it means your heart is working much harder to pump blood throughout your body. “You can sort of think of high blood pressure as your blood punching the walls of the heart and other organs over and over again,” says Dr Philips. “If that punching is at a high force, you’re going to develop thickening and damage over time.”

According to the Heart Foundation, anything between 120/80 mmHg and 139/89 mmHg is considered normal to high range, while anything over 140/90 mmHg is considered high blood pressure. The good news: Elevated and high blood pressure can often (but not always) be addressed with diet and lifestyle modifications, says Dr Philips.

Step one: Figure out what’s causing your high blood pressure in the first place. For most people, it’s multifactorial, meaning a bunch of factors work in tandem to spike your levels into unsafe territory. Here, the most common causes of blood pressure and how to address them to bring your numbers back down.