High Blood Pressure (Hypertension): Complete NHS Guide
High blood pressure (hypertension) affects around 14 million people in the UK and is a major risk factor for heart attack and stroke. It is sometimes called the “silent killer” because it usually has no symptoms. This guide explains NHS blood pressure thresholds, diagnosis, and treatment.
- UK prevalence: ~14 million people; many undiagnosed
- Normal BP: Below 120/80 mmHg
- NHS treatment threshold: 140/90 mmHg or above (clinic) / 135/85 mmHg (home monitoring)
- High-risk threshold: 180/120 mmHg — seek urgent care
- First-line treatment: Lifestyle changes + ACE inhibitor or calcium channel blocker
Understanding Blood Pressure Readings
Blood pressure is measured in millimetres of mercury (mmHg) and given as two numbers. The higher number (systolic) measures pressure when the heart contracts; the lower number (diastolic) measures pressure when the heart rests between beats.
- Normal: Below 120/80 mmHg
- Elevated: 120–129 / below 80 mmHg
- Stage 1 hypertension: 130–139 / 80–89 mmHg
- Stage 2 hypertension: 140/90 mmHg or above
- Hypertensive crisis: 180/120 mmHg or above — seek immediate medical advice
NHS Diagnosis and Monitoring
High blood pressure is typically diagnosed if readings are consistently elevated across multiple readings. The NHS recommends ambulatory blood pressure monitoring (ABPM) — wearing a blood pressure monitor for 24 hours to take readings at regular intervals — as the most accurate diagnostic method. Home blood pressure monitoring (HBPM) is an acceptable alternative.
Treatment
Lifestyle changes are always the foundation: reduce salt intake (under 6g/day), eat a balanced diet rich in fruit and vegetables, exercise regularly, reduce alcohol, stop smoking, and manage stress. These alone can lower blood pressure by 5–10 mmHg.
NHS medication (NICE guidelines): Under 55 with no diabetes — ACE inhibitor (e.g. ramipril) or angiotensin receptor blocker (ARB) first-line. Over 55 or Black African/Caribbean heritage — calcium channel blocker (e.g. amlodipine) first-line. A thiazide diuretic may be added as second-line. Your GP will review your medication regularly.
Disclaimer: Educational information only. Consult your GP about your blood pressure. Full disclaimer →
Frequently Asked Questions
What blood pressure reading is considered high?
A reading consistently at or above 140/90 mmHg is classified as high blood pressure (hypertension). Optimal blood pressure is below 120/80 mmHg. Your GP will usually take several readings over time — or use home monitoring — before making a formal diagnosis, as blood pressure naturally varies.
Can high blood pressure be treated without medication?
Mild hypertension can sometimes be managed through lifestyle changes: reducing salt intake to under 6g per day, taking regular aerobic exercise, maintaining a healthy weight, limiting alcohol, quitting smoking, and managing stress. If lifestyle changes are insufficient, your GP will recommend antihypertensive medication.
What are the risks of untreated high blood pressure?
Untreated hypertension significantly increases the risk of heart attack, stroke, heart failure, kidney disease, and vascular dementia. High blood pressure rarely causes noticeable symptoms, which is why regular checks are essential. The NHS offers free Health Checks every 5 years for adults aged 40–74.