Written by
Louise W Lu, PhD, MPH, BMLS
Reviewed by
Alexandra V Goldberg, Registered Dietitian
Ever wondered why one doctor tells you your blood pressure is fine at 135/85, while another says it’s already high?
You’re not alone. The definition of high blood pressure—also known as hypertension—can vary depending on where you live and which medical guidelines your doctor follows.
Let’s explore why that is, and what those numbers really mean for your health.
What is Blood Pressure?
Blood pressure is a measurement of how hard your blood pushes against the walls of your arteries as your heart pumps it around your body. It tells us how much force is being used inside your blood vessels.
Blood pressure is written as two numbers, such as 120/80 mmHg:
- Systolic pressure (the top number): the force when your heart contracts and pushes blood out.
- Diastolic pressure (the bottom number): the pressure when your heart relaxes between beats.
What Makes Blood Pressure High?
It’s considered high when the force inside your arteries is consistently too strong. Over time, this extra pressure can damage your blood vessels and organs.
Why Is High Blood Pressure Dangerous?
High blood pressure usually doesn’t cause symptoms at first—so it’s called a “silent killer.” But if left untreated, it can:
- Cause heart attack and stroke
- Lead to kidney failure
- Cause vision loss or dementia
How Do Guidelines Define and Classify High Blood Pressure?
Different health organisations define high blood pressure using different numbers. This affects when a diagnosis is made and when treatment begins.
Defines Hypertension As
This is the blood pressure number that counts as “high.”
- WHO: 140/90 mmHg or higher
- AHA/ACC (U.S.): 130/80 mmHg or higher
Treatment Target
Once you’re diagnosed and treated, doctors aim to bring your BP down to a “safe zone.”
- WHO: below 140/90 mmHg (or below 130 for high-risk patients)
- AHA/ACC: below 130/80 mmHg for most people
Hypertension Stages
Doctors divide hypertension into stages to help guide treatment:
| Category | Systolic | Diastolic |
|---|---|---|
| Normal | <120 | <80 |
| Elevated (USA only) | 120–129 | <80 |
| Stage 1 | 130–139 | 80–89 |
| Stage 2 | ≥140 | ≥90 |
Global Blood Pressure Guidelines Compared (2024)
| Organization | Defines Hypertension As | Treatment Target | Key Feature |
|---|---|---|---|
| World Health Organization (WHO) | ≥140/90 | <140/90 (or <130 for high-risk patients) | Simple and globally applicable |
| American Heart Association / American College of Cardiology (AHA/ACC) | ≥130/80 | <130/80 | Focus on early prevention |
| European Society of Cardiology / European Society of Hypertension (ESC/ESH) | ≥140/90 | <140 (or <130 if tolerated) | Risk-based approach |
| China: National Guideline (Joint Committees) | ≥140/90 | <130/80 (for some populations) | Practical and adaptable |
| Japanese Society of Hypertension (JSH) | ≥140/90 | <130/80 (<75 yrs), <140/90 (≥75 yrs) | Age-based targets |
| Taiwan Society of Hypertension (TSH) | ≥130/80 (home); ≥140/90 (clinic) | <130/80 | Emphasis on home monitoring |
| Australia: National Health and Medical Research Council (NHMRC) | ≥140/90 | <140/90 (general); <130/80 (high-risk) | Realistic and risk-adjusted |
| New Zealand: Heart Foundation NZ | ≥140/90 | <140/90 (general); <130/80 (high-risk) | Aligned with Australian standards |
Why Are Guidelines Different?
Not all countries use the same blood pressure numbers because healthcare systems and population needs are different.
Access to Healthcare
WHO uses 140/90 mmHg because in many places, people don’t see doctors regularly. A higher threshold keeps things simple.
In countries like the U.S., people can check their blood pressure more often and get treated sooner, so AHA uses 130/80 mmHg.
Different Health Risks
In the U.S., heart disease starts earlier, so early treatment matters more. In Japan and Europe, people live longer and may not need aggressive treatment unless risks are high.
Why AHA Might Be Better If You Have Access
If you have good access to doctors and support, the AHA's lower target gives you the best chance to avoid problems like stroke, heart attack, or kidney damage—often before they start.
So Which Guideline Should You Follow?
If you live in a place with strong healthcare and regular checkups, the AHA guidelines are a smart choice:
- They catch problems earlier
- They emphasise lifestyle changes
- They’re based on strong research
But wherever you live, understanding the goal—and taking action—matters most.
Final Takeaway
Blood pressure guidelines may differ, but the goal is the same: protect your health.
Know your numbers. Monitor them. And work with your doctor to keep them in a safe range—because your heart deserves it.
