High Blood Pressure Explained: What Your Reading Means

ByFamily Doctor Editorial

About one in three Australian adults has high blood pressure — many without knowing it. It’s painless, silent, and sits quietly in the background as the largest single risk factor for stroke, heart attack, and kidney disease. A quick blood pressure check at your GP is one of the most valuable health actions you can take.

What the Numbers Mean

Your blood pressure is written as two numbers — for example, 120/80 mmHg:

  • Systolic (top number) — pressure in your arteries when the heart contracts (pumps out blood).
  • Diastolic (bottom number) — pressure when the heart is between beats (refilling).

Both matter. A high systolic (especially in older adults) is a particularly strong predictor of stroke and heart attack.

Blood Pressure Categories

  • Optimal — less than 120/80 mmHg.
  • Normal — 120-129 / 80-84 mmHg.
  • High-normal — 130-139 / 85-89 mmHg. Lifestyle changes recommended; monitor.
  • Grade 1 hypertension (mild) — 140-159 / 90-99 mmHg. Lifestyle changes; medication often needed.
  • Grade 2 hypertension (moderate) — 160-179 / 100-109 mmHg. Medication usually needed; lifestyle too.
  • Grade 3 hypertension (severe) — 180+ / 110+ mmHg. Urgent medical review.

A single high reading doesn’t mean you have hypertension. Diagnosis requires elevated readings on multiple occasions, plus home or 24-hour ambulatory monitoring to rule out “white coat” effect (the clinic reading being artificially high).

Why High Blood Pressure Matters

Over time, high blood pressure damages:

  • Brain — major cause of stroke and contributes to vascular dementia
  • Heart — increases risk of heart attack, heart failure, and atrial fibrillation
  • Kidneys — leading cause of chronic kidney disease
  • Eyes — damage to retinal blood vessels can affect vision
  • Arteries — accelerates atherosclerosis (artery narrowing)

Lifestyle Changes That Lower Blood Pressure

  • Reduce salt intake — aim for less than 5g of salt daily; most of it comes from processed and restaurant foods.
  • Increase potassium — fruit, vegetables, beans, and potatoes help counter sodium’s effects.
  • Lose weight if overweight — each kilogram of weight loss typically drops systolic BP by around 1 mmHg.
  • Exercise regularly — 150 minutes of moderate aerobic activity per week (brisk walking, cycling, swimming).
  • Limit alcohol — no more than 10 standard drinks per week; no more than 4 in a single day.
  • Quit smoking — every cigarette temporarily spikes blood pressure.
  • Manage stress — chronic stress contributes; mindfulness, sleep, and social support help.
  • Sleep enough — 7-9 hours; sleep apnoea in particular is a common and treatable cause of high BP.

Medications

If lifestyle changes aren’t enough, medications are highly effective and well tolerated for most people. Common classes your GP may prescribe:

  • ACE inhibitors (e.g., perindopril, ramipril) — first-line for most patients
  • Angiotensin receptor blockers (ARBs) (e.g., telmisartan, irbesartan) — alternative to ACE inhibitors
  • Calcium channel blockers (e.g., amlodipine, felodipine)
  • Thiazide diuretics (e.g., indapamide, hydrochlorothiazide)
  • Beta blockers — used in specific circumstances

Many people need two or three medications to achieve good control. Modern combination tablets make this simpler — one pill can contain two or three active ingredients.

Home Blood Pressure Monitoring

An automatic upper-arm cuff from a pharmacy (look for models validated by Hypertension Australia) gives more reliable readings than clinic checks alone. Take readings at the same times each day, when relaxed, with back supported and feet on the floor. Share the log with your GP.

Frequently Asked Questions

Why does my GP get a different reading than my home monitor?

“White coat hypertension” is common — clinic readings are often 5-15 mmHg higher than home readings due to stress. Home and 24-hour monitoring give a truer picture.

Can I stop my blood pressure medication once my reading is normal?

In most cases, no — the medication is keeping the reading normal. Stopping it usually means the pressure rises again. Your GP may reduce the dose if lifestyle changes produce strong sustained reductions.

Is high blood pressure hereditary?

Genetics plays a significant role. If a parent or sibling has hypertension, you’re at higher risk — start monitoring earlier.

What about salt substitutes?

Potassium-based salt substitutes can help lower blood pressure — but they’re not safe for everyone. If you have kidney disease or take certain medications, they can cause dangerous potassium levels. Discuss with your GP first.

How urgent is a reading of 180/100?

A reading that high needs same-day medical review. If accompanied by chest pain, severe headache, vision changes, or breathlessness, call 000.

Book a Blood Pressure Check

A quick check takes 5 minutes and could add years to your life. Find your nearest Family Doctor clinic and book a short GP appointment — or ask for a nurse-led blood pressure review.

Similar Posts