Understanding high blood pressure

What blood pressure is

Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps. It is written as two numbers: the systolic pressure, when the heart contracts, and the diastolic pressure, when the heart relaxes between beats, measured in millimetres of mercury (mmHg).

Pressure rises and falls through the day with activity, stress, sleep and posture. A single high reading does not by itself establish hypertension; diagnosis rests on repeated measurements, sometimes confirmed with home or 24-hour monitoring.

Why it matters

High blood pressure usually causes no symptoms, which is why it is often found only by measuring it. Over years, uncontrolled pressure damages artery walls and raises the risk of heart attack, stroke, kidney disease, heart failure and damage to the eyes and blood vessels.

It is one of the most common long-term conditions worldwide, and many people who have it do not know. Measuring blood pressure is simple and is the only way to find it.

What influences it

Blood pressure tends to rise with age. Factors that raise the risk of lasting high pressure include high salt intake, low physical activity, excess weight, alcohol, smoking, poor sleep and a family history of hypertension. Some medicines and some kidney, hormonal and pregnancy-related conditions can also raise it.

Management usually combines everyday measures - less salt, more activity, weight management, limiting alcohol - with medication when a clinician judges it needed. Treatment targets and drug choices are individual decisions made with the treating clinician.

What this overview cannot do

This is general information, not clinical guidance for any one person. It cannot interpret a specific reading, say whether someone has hypertension, or recommend starting or stopping any medicine. Those decisions belong with a qualified clinician who knows the person's history.