What is it?
High blood pressure — known medically as hypertension — means the force of blood pushing against the walls of the arteries is consistently too high. Think of it like water pressure in a hosepipe: if the pressure is always too strong, over time it starts to damage the pipe itself.
Blood pressure is recorded as two numbers. The top number (systolic) measures the pressure when the heart beats. The bottom number (diastolic) measures the pressure between beats when the heart is resting. A reading is written as, for example, 120/80 mmHg (millimetres of mercury — the standard unit of pressure measurement) — said as "120 over 80."
A reading of 140/90 mmHg or above, confirmed on more than one occasion, is how hypertension is clinically defined in UK practice. Many people have no symptoms at all — which is why it is often described as a silent condition. It can be present for years without any awareness of it.
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Why does it matter?
Raised blood pressure puts constant extra strain on the heart, arteries, brain, kidneys, and eyes. Over time this cumulative damage is significant — even in the complete absence of symptoms. Hypertension is one of the leading causes of stroke, heart attack, heart failure, and chronic kidney disease in the UK.
The scale of undetected hypertension — both in the UK and globally — underlines why blood pressure checking in routine healthcare contacts matters. The condition is treatable, the evidence base is strong, and the cardiovascular benefit of even modest reductions in blood pressure is well established.
What your doctor might do
Confirming the diagnosis
In UK practice, a 24-hour blood pressure monitor worn at home — ambulatory blood pressure monitoring (ABPM) — is the standard approach to confirming a hypertension diagnosis. This provides a more accurate picture of blood pressure across everyday activity than a single clinic reading, and avoids the effect of white coat hypertension, where the clinical setting temporarily elevates readings through anxiety or stress.
Where ABPM is not suitable, home readings taken twice a day over several days are used instead.
Checking for organ effects and cardiovascular risk
Assessment typically includes blood tests, a urine test, and sometimes a heart trace (ECG — electrocardiogram — recording the heart's electrical activity) to establish whether elevated blood pressure has affected the kidneys or heart. An eye examination may also be included, as the small blood vessels at the back of the eye can show early signs of hypertensive damage.
Together these investigations provide an overall picture of cardiovascular risk — assessed using a validated risk calculator as part of standard UK clinical practice.
Management — lifestyle and medication
The approach depends on how high blood pressure is and what other health factors are present. For many people, lifestyle measures alone produce meaningful reductions — salt reduction, weight management, regular aerobic exercise, reduced alcohol intake, and smoking cessation are all recognised as having evidence-based blood pressure-lowering effects.
Where medication is indicated, UK practice follows NICE guideline NG136,7 which identifies three main drug classes depending on age and clinical factors: ACE inhibitors or ARBs, calcium channel blockers, or thiazide-like diuretics. Management on a combination of two or more is common.
Once treatment is established, blood pressure monitoring continues to confirm that targets are being achieved. In UK practice, the target for most people under 80 is below 140/90 mmHg in clinic (or below 135/85 mmHg on home monitoring). For those aged 80 and over, targets are slightly higher — below 150/90 mmHg in clinic, or below 145/85 mmHg on home monitoring — in line with NICE NG136.7
What the research shows
Hypertension is one of the most common and most consequential conditions in the UK — affecting around 1 in 3 adults and driving enormous numbers of strokes, heart attacks, and episodes of kidney disease each year. Its defining feature is silence: most people have no symptoms, and diagnosis typically comes through routine checking rather than any clinical warning.
The evidence for treatment is strong. Even modest reductions in blood pressure — as little as 5 mmHg systolic — produce meaningful reductions in cardiovascular events across all risk groups. Lifestyle measures have real, quantifiable effects and are a recognised component of management at every stage. Where medication is indicated, UK practice follows a well-established NICE-guided pathway.
Understanding what hypertension is, what the numbers mean, and how it is managed in UK practice is the foundation for any informed conversation about blood pressure — whether that is at a routine check, following an incidental finding, or after a formal diagnosis. That conversation belongs with a GP or healthcare professional.