In simple terms
Blood pressure is the force of blood pushing against the walls of your blood vessels. Hypertension means that force stays too high over time.
Most people with hypertension feel nothing at all. That is why a measurement is the only reliable way to find out.
How it works
A reading has two numbers, written in millimeters of mercury (mmHg). The first, systolic, is the pressure in the vessels when the heart beats. The second, diastolic, is the pressure when the heart rests between beats.
Where the line is drawn depends on the guideline:
- World Health Organization: 140/90 mmHg or higher.
- United States (2025 AHA/ACC guideline): stage 1 starts at 130/80 mmHg and stage 2 at 140/90 mmHg.
Because thresholds differ, the number a clinician uses depends on where you live and your overall health.
Why it matters
Over time, high pressure can damage the heart and lead to chest pain, heart attack or heart failure. It can also burst or block arteries that supply the brain, causing a stroke, and it can damage the kidneys. WHO describes hypertension as a major cause of premature death worldwide.
WHO advises urgent care for very high readings that come with symptoms such as severe headache, chest pain, dizziness, difficulty breathing or blurred vision.
Where you’ll see it
- Routine health checks at clinics and pharmacies.
- Global health reporting, including WHO estimates of how many people are affected.
- Public health advice about diet, physical activity, tobacco and alcohol.
Example
A reading of 145/92 mmHg is above the WHO threshold of 140/90 mmHg.
Often confused with
Hypotension: blood pressure that is too low, the opposite condition.
Key facts
- About 1.4 billion adults aged 30 to 79 had hypertension in 2024, about one in three worldwide.1
- About 44% of adults with hypertension did not know they had it.1
- Only about 23% of adults with hypertension had it under control.1
- Risk factors that can be changed include unhealthy diet, physical inactivity, tobacco and alcohol use, and excess weight.1
- The 2025 AHA/ACC guideline classes a reading of 120 to 129 systolic with under 80 diastolic as elevated blood pressure, just below the hypertension range.2
This entry explains a medical term. It is not medical advice. If you are concerned about your health, speak with a qualified health professional.
Go deeperWhat Actually Causes High Blood Pressure?In the news
Quick checkIn a reading of 130/85, what does the first number measure?Show answer
The pressure in your blood vessels when your heart beats (systolic pressure).
Sources
- World Health Organization. Hypertension (fact sheet). 25 September 2025 (accessed 11 September 2026)
- American Heart Association. 2025 High Blood Pressure Guideline: top things to know. 2025 (accessed 11 September 2026)
Editorially reviewed by Specialty Digest Editorial TeamLast reviewed September 11, 2026Researched and drafted with AI assistanceReport an issue