High Blood Pressure: Symptoms, Diagnosis and How to Lower It

What is blood pressure?

Blood pressure is the force your blood exerts on the walls of your arteries. It is recorded as two numbers in millimetres of mercury (mmHg): the systolic pressure (the higher number, when your heart beats) and the diastolic pressure (the lower number, when your heart rests between beats). A reading of 120/80 mmHg is described as "120 over 80".

High blood pressure (hypertension) puts extra strain on the heart, blood vessels, kidneys and brain. Over time it raises the risk of heart attack, stroke, heart failure, kidney disease and vascular dementia. The British Heart Foundation estimates that around a third of adults in the UK have high blood pressure, and that millions are living with it undiagnosed.

Why it is called a "silent" condition

Most people with high blood pressure feel completely well. Headaches, nosebleeds or blurred vision are uncommon and usually only occur when blood pressure is very high. The only reliable way to know your numbers is to have them measured. The NHS recommends that all adults over 40 have their blood pressure checked at least every five years, and more often if you have other risk factors.

What do the numbers mean?

Category	Clinic reading	Home / ambulatory average
Ideal	90/60 to 120/80 mmHg	—
Stage 1 hypertension	140/90 to 159/99 mmHg	135/85 to 149/94 mmHg
Stage 2 hypertension	160/100 mmHg or higher	150/95 mmHg or higher
Severe hypertension	Systolic 180+ or diastolic 120+	Needs same-day medical review

Source: NICE guideline NG136, Hypertension in adults: diagnosis and management.

How high blood pressure is diagnosed

A single raised reading is not enough for a diagnosis, because blood pressure naturally varies and can rise in a clinical setting ("white coat" effect). Under NICE guidance, if your clinic reading is 140/90 mmHg or above you should be offered ambulatory blood pressure monitoring (ABPM) over 24 hours, or home blood pressure monitoring (HBPM) for at least four days, to confirm it.

If you are diagnosed, your clinician will also check for damage to organs (such as a urine test, blood tests and an ECG) and estimate your 10-year cardiovascular risk.

Who is most at risk?

• People over 65, although it can affect younger adults
• People with a family history of high blood pressure
• People of Black African or Black Caribbean descent
• People who are overweight, inactive, smoke, drink heavily or eat a lot of salt
• People with diabetes or kidney disease

Proven ways to lower blood pressure

Lifestyle changes help everyone with raised blood pressure and may be enough on their own for some people.

• Cut down on salt: adults should have no more than 6 g of salt a day (about a teaspoon). Most salt is already in bread, cereals, ready meals and processed meat.
• Stay active: the UK Chief Medical Officers recommend at least 150 minutes of moderate activity, such as brisk walking or cycling, each week.
• Limit alcohol: keep to no more than 14 units a week, spread over three or more days.
• Lose excess weight: even a modest reduction can lower blood pressure.
• Eat well: plenty of fruit, vegetables and whole grains, and less saturated fat.
• Stop smoking: smoking does not cause long-term high blood pressure on its own, but it greatly increases the risk of heart and circulatory disease.

Medicines for high blood pressure

If you need medicine, the choice depends on your age, ethnicity and other conditions. Common first-line options include ACE inhibitors (such as ramipril), angiotensin receptor blockers (such as losartan) and calcium channel blockers (such as amlodipine). Many people need more than one medicine. Keep taking them even when you feel well, and speak to your pharmacist if you notice side effects such as a persistent dry cough or ankle swelling.

Treatment targets

• Under 80: below 140/90 mmHg in clinic (below 135/85 mmHg at home)
• 80 and over: below 150/90 mmHg in clinic (below 145/85 mmHg at home)

Your target may be different if you have diabetes, kidney disease or another condition, so check with your GP or pharmacist.

Free blood pressure checks at your pharmacy

Through the NHS Pharmacy Blood Pressure Check Service, adults aged 40 and over in England who have not been diagnosed with high blood pressure can have a free check at a participating pharmacy. If your reading is raised, the pharmacist can offer ambulatory monitoring and share the results with your GP.

When to seek urgent help

Call 999 if you have a very high reading together with chest pain, shortness of breath, sudden weakness, confusion, difficulty speaking or a severe headache. These can be signs of a heart attack, stroke or hypertensive emergency.