The short version
- High blood pressure produces no symptoms until damage is already done
- One high reading is not a diagnosis — the pattern over time is what counts
- Home readings, taken properly, are often more useful than clinic readings
- Salt, alcohol, weight, activity and sleep apnoea all move the number measurably
What the two numbers are
The top number (systolic) is the pressure in your arteries when the heart contracts. The bottom number (diastolic) is the pressure between beats. Both matter, though systolic becomes the more important predictor with age.
As a general guide, under 120/80 is optimal and 140/90 or above, measured consistently, is generally considered high. Your own target may differ — age, diabetes, kidney disease and other conditions all shift it, and in older adults an aggressive target can cause harm.
Why one reading proves nothing
Blood pressure varies constantly — with the time of day, stress, caffeine, a full bladder, talking, and the walk in from the car park. A single high reading in a clinic is common and often not representative.
This is why your GP may ask for home readings, or arrange 24-hour ambulatory monitoring. White-coat hypertension (high here, normal at home) and masked hypertension (normal here, high at home) are both real, and only measurement outside the clinic distinguishes them.
How to take a reading that means something
- Sit quietly for five minutes first, feet flat, back supported
- Arm supported at heart height, cuff on bare skin and the right size
- No caffeine, smoking or exercise in the 30 minutes beforehand
- Do not talk during the reading
- Take two readings a minute apart, morning and evening, for seven days — and bring the lot to your appointment
Discard the first day when averaging, as it tends to read high. Write the numbers down rather than relying on the machine's memory.
What actually lowers it
The changes with the most evidence behind them are unglamorous and they work: reducing salt (most of which comes from processed food rather than the shaker), reducing alcohol, regular aerobic activity, weight loss where there is excess weight, and treating obstructive sleep apnoea, which is a common and frequently missed driver of resistant high blood pressure.
Medication is added when lifestyle change is not enough, or when the starting point or overall cardiovascular risk is high. It is not a failure and it is not necessarily permanent. Your GP will discuss options with you — prescription medicines cannot be named in public health information under Australian law.
Why it matters if you feel fine
You will feel fine. That is the point. Sustained high pressure damages arteries silently, raising the risk of stroke, heart attack, heart failure, kidney disease and vision loss over years — and most of that risk is reversible if it is treated before the damage accumulates.
From 45 (or 30 for Aboriginal and Torres Strait Islander people), a Heart Health Check combines your numbers, age, family history and habits into a percentage risk over the next five years, which is a far more useful figure than blood pressure alone. See health assessments.
Common questions
Not on its own. Blood pressure varies constantly. Diagnosis rests on a pattern of readings, often including home or 24-hour monitoring.
Often, yes — reducing salt and alcohol, regular activity, weight loss where relevant and treating sleep apnoea all help. Whether that is enough depends on your starting point and overall risk.
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