Hypertension (High Blood Pressure)

Blood pressure (BP) is a measurement of the pressure of fluid (blood) within your circulatory system. The bodies circulation is a bit like a closed central heating system in which the heart is the pump, and the blood vessels (arteries & veins) are the pipes.

As the heart contracts (systole) it pumps out a pressure wave (pulse) which temporarily raises the pressure within the system. As the heart relaxes between contractions (diastole) the pressure within the system drops.

The BP reading records the highest (systolic) and lowest (diastolic) pressures within the circulatory system during this cycle and expresses them in millimetres of mercury (mmHg).

In a healthy circulatory system, the pipes (blood vessels) have flexible walls rather like a piece of rubber tubing. However, over time the vessel walls stiffen and become less flexible which can lead to a rise in the baseline blood pressure. Several factors will influence this process including lifestyle factors, age and family history.

If the blood pressure remains too high, it can accelerate the process of atherosclerosis which leads to narrowing of the blood vessels, particularly the arteries and to further stiffening of the vessel walls. This can eventually cause a restriction of blood flow through the arteries (e.g. angina, vascular dementia & kidney disease) or even to a complete blockage of blood flow (e.g. heart attacks & strokes).

A persistently raised blood pressure also means that the heart must work harder to pump blood through the circulatory system and over time this can lead to enlargement (hypertrophy) of the heart and even heart failure.

It is therefore important to identify and treat persistently raised blood pressure as early as possible to prevent the progression to serious disease.

Low blood pressure (hypotension) is less common than high blood pressure. Some medicines can cause low blood pressure as a side effect. It can also be caused by a number of underlying conditions, including heart failure and dehydration. The symptoms of low blood pressure are tiredness, dizziness and feeling light-headed or faint, particularly when standing from sitting or lying.

Blood pressure is expressed in millimetres of mercury (mmHg) and is given as 2 figures:

• systolic pressure – the pressure when your heart pushes blood out
• diastolic pressure – the pressure when your heart rests between beats

For example, if your blood pressure is “140 over 90” or 140/90mmHg, it means that you have a systolic pressure of 140mmHg and a diastolic pressure of 90mmHg.

As a general guide:

• ideal blood pressure is between 90/60mmHg and 120/80mmHg
• low blood pressure is 90/60mmHg or lower
• high blood pressure is 140/90mmHg or higher

Blood pressure readings between 120/80mmHg and 140/90mmHg could mean that you’re at risk of developing high blood pressure unless you take steps to keep your blood pressure under control.

A blood pressure greater than 180/110 could represent severe hypertension and should prompt an early assessment by your GP. If accompanied by symptoms such as visual disturbance or headache you should seek an immediate medical assessment either by your GP or via A&E.

The only way of knowing whether you have high blood pressure is to have a blood pressure test.

All adults over 40 are advised to have their blood pressure checked at least once every 5 years. Getting this done is easy and could save your life.

You can get your blood pressure tested at a number of places, including:

• at your GP surgery
• at some pharmacies
• as part of your NHS Health Check
• in some workplaces

You can also check your blood pressure yourself with a home blood pressure monitor.

Blood pressure tests can be done at home using your own blood pressure monitor. This is likely to give a better indication of your normal blood pressure than “one-off” measurements taken in a clinical environment because being tested in somewhere like a GP surgery can make you feel anxious and can affect the result. Home testing can also allow you to monitor your condition more easily in the long term.

A variety of low-cost blood pressure monitors are available to buy but it’s important to make sure that you use equipment which has been properly calibrated and tested. The British & Irish Hypertension Society (BIHS) has information about validated BP monitors that you can buy over the counter. It produces the only independent, peer-reviewed list of blood pressure monitors that is not governed by commercial interest.

The BIHS also produces a template Home Blood Pressure Diary which can be downloaded free.  See here for guidelines on how to take your blood pressure at home.

Find out more about home blood pressure monitoring here.

Find out more about getting a blood pressure test here.

In some cases, your doctor may recommend 24-hour or ambulatory blood pressure monitoring (ABPM). This is where your blood pressure is tested automatically around every 30 minutes over a 24-hour period using a cuff attached to a portable recording device worn on your waist.

ABPM can help to give a clearer picture of how your blood pressure changes over the course of a day.

You should continue with your normal daily activities during the test, although you must avoid getting the equipment wet.

If your blood pressure is too high then over time it puts extra strain on your blood vessels, heart and other organs, such as the brain, kidneys and eyes.

Persistently high blood pressure can increase your risk of a number of serious and potentially life-threatening health conditions, such as:

• heart disease
• heart attacks
• strokes
• heart failure
• peripheral arterial disease
• aortic aneurysms
• kidney disease
• vascular dementia

If you have high blood pressure then reducing it, even by a small amount, can help lower your risk of these health conditions.

High blood pressure is one of several factors that contribute to atherosclerosis (hardening of the arteries) which in turn can lead to kidney disease, heart attacks and strokes (collectively known as cardiovascular disease or CVD).

Other factors leading to CVD include smoking, high cholesterol, diabetes and obesity. Whilst addressing high blood pressure can help prevent cardiovascular disease (“primary prevention”) it is particularly important to control blood pressure in people with diabetes or pre-existing cardiovascular disease in order to reduce the risks of disease progression and life-threatening complications such as strokes and heart attacks (“secondary prevention”). It is therefore essential that patients with diabetes or known CVD attend their GP surgery regularly (at least once a year) for review and monitoring.

High blood pressure in pregnancy can lead to serious complications and needs specialist monitoring and management.

The cause of raised blood pressure is not always clear and is generally due to a number of factors. This form of hypertension is called Essential Hypertension.

Other causes include:

• Renal (kidney) disease
• Endocrine (hormone) disease – Cushings, Conns Syndrome, carcinoid, phaeochromocytoma
• Coarctation (narrowing) of the aorta
• Iatrogenic (drug-induced) – e.g., corticosteroids

Known risk factors for developing hypertension include:

• being overweight
• eating too much salt and not eating enough fruit and vegetables
• lack of exercise
• drinking too much alcohol or coffee (or other caffeine-based drinks)
• smoking
• not getting enough sleep or having disturbed sleep
• increasing age (over 65yrs old)
• having a relative with high blood pressure
• being of black African or black Caribbean descent
• living in a deprived area

Making healthy lifestyle changes can help reduce your chances of getting high blood pressure and help lower your blood pressure if it’s already high.

The initial management of raised blood pressure is usually through lifestyle changes, particularly focusing on diet, weight, exercise and smoking cessation. Where these fail to bring your blood pressure down to normal limits your doctor may advise the additional use of medication.

What works best is different for each person, so it is best to talk to a health care professional to help you decide about treatment.

This patient decision aid (PDF, 132kb) can also help you to understand your treatment options.

The National Institute for Health & Care Excellence (NICE) guidance uses ambulatory or home monitoring to classify Hypertension as stage 1 or stage 2:

Stage 1 hypertension:

• Clinic blood pressure is 140/90 mmHg or higher and
• subsequently ambulatory blood pressure monitoring (ABPM) daytime average or home blood pressure monitoring (HBPM) average blood pressure is 135/85 mmHg or higher
• Consider drug treatment if aged under 80yrs and additional risk factors – diabetes, renal disease, CVD or 10-year CVD risk greater than 20%, evidence of end organ damage
• Clinic blood pressure is 160/100 mmHg or higher AND
• subsequently ABPM daytime average or HBPM average blood pressure is 150/95 mmHg higher
• Consider drug treatment for all
• Clinic systolic blood pressure is 180 mmHg or higher or clinic diastolic blood pressure is 110 mmHg or higher
• Start drug treatment immediately

Stage 2 hypertension:

• Clinic blood pressure is 160/100 mmHg or higher AND
• subsequently ABPM daytime average or HBPM average blood pressure is 150/95 mmHg higher
• Consider drug treatment for all

Severe Hypertension:

• Clinic systolic blood pressure is 180 mmHg or higher or clinic diastolic blood pressure is 110 mmHg or higher
• Start drug treatment immediately

Lifestyle changes

These lifestyle changes can help prevent and lower high blood pressure:

• reduce the amount of salt you eat and have a generally healthy diet
• cut back on alcohol (Men 21 units or under per week, Women 14 units or under per week)
• lose weight if you’re overweight (target BMI = 20-25)
• exercise regularly (at least 30 minutes most days)
• cut down on caffeine
• stop smoking

The U.S. National Institute for Heart & Lungs has developed guidelines for Dietary Approaches to Stop Hypertension (DASH) which can be downloaded in .pdf form here.

Medicines

If you are unable to reduce your blood pressure by lifestyle changes alone or your blood pressure is particularly high, then you may be advised to take regular medication in the form of tablets. These usually need to be taken once a day.

Many of these medicines not only lower your blood pressure but also appear to protect against the complications of raised blood pressure such as enlargement of the heart and kidney problems.

These medications usually need to be continued long-term once the blood pressure is controlled because if they are discontinued the blood pressure is likely to rise once again.

Common blood pressure medicines include:

• ACE inhibitors – such as enalapril, lisinopril, perindopril and ramipril
• angiotensin-2 receptor blockers (ARBs) – such as candesartan, irbesartan, losartan and valsartan.
• calcium channel blockers – such as amlodipine, felodipine and nifedipine or diltiazem and verapamil
• diuretics – such as indapamide and bendroflumethiazide
• beta blockers – such as atenolol and bisoprolol
• alpha blockers – such as doxazosin
• other diuretics – such as amiloride and spironolactone

The medicine recommended for you will depend on things like how high your blood pressure is, your age and your ethnicity.

Device-guided breathing (Resperate®)

Results from randomised trials involving the Resperate® device are contradictory, although it would appear the device may reduce blood pressure by approximately 3.5/2.5mmHg when used over an 8-week period. The long-term effectiveness of Resperate is not known.

The British Hypertension Society (BHS) advises that there is currently insufficient evidence to recommend the use of Resperate devices.

In the absence of long-term efficacy data involving patient-centred outcomes Resperate® devices will not be prescribed on NHS prescriptions. Patients wishing to use Resperate® may purchase the device privately.

• How to check your blood pressure
• Keeping Fit – how to do the right exercise for your age
• British Heart Foundation healthy eating
• Lowering Your Blood Pressure – DASH Eating Plan

Blood Pressure UK – How to measure your blood pressure at home

Published: 25 August 2020

British Heart Foundation – How to measure your own blood pressure

Published: 14 January 2015

• Home Blood Pressure Diary – British Hypertension Society
• Measuring Your Blood Pressure At Home – Blood Pressure UK

It is relatively unusual for patients to require a specialist opinion for high blood pressure, but this may be suggested by your GP if you develop high blood pressure at a young age or if your GP is unable to control your blood pressure with usual medical treatments.

If you have been referred for a specialist opinion your details will be reviewed and it may be recommended that you are seen by a hospital clinician, or the specialist may write back to your GP with advice. Information to support you in choosing your preferred hospital, including waiting times can be found using the links below.

How long will I wait?

If a hospital assessment and/or treatment is clinically recommended your information will be sent to a specialist. Click below to find out more about waiting times for routine hospital assessment and/or treatment.

• Waiting times
• Find services near you