High blood pressure (hypertension)


High blood pressure, or hypertension, is a common and dangerous condition that usually has no symptoms. It affects up to 1 in 2 adults in America and more than 1 in 4 in the UK – and many do not know they have it.  High blood pressure increases your risk of strokes, heart attacks and many other conditions.  

What is high blood pressure?

Blood being pumped round your body by your heart exerts pressure inside your blood vessels. The pressure increases as the heart pumps and drops as the heart rests between beats. Blood pressure is measured in ‘millimetres of mercury’ (written as ‘mm Hg’). It is given as two numbers, for example 120/80mm Hg, often referred to as ‘120 over 80’. The first, higher number, is the maximum pressure in your arteries as the heart pumps – systolic pressure – and second is the minimum pressure as the heart relaxes – diastolic pressure. 

Any reading between 90/60mm Hg and 120/80mm Hg is in the normal range. Since 1997, blood pressure between 120/80mm Hg and 140/90mm Hg has been considered raised (known as prehypertension). And people whose blood pressure is sustained at 140/90mm Hg or above were deemed to have high blood pressure, or hypertension. This remains the case in the UK.

In late 2017, however, guidelines from the American College of Cardiology and the American Heart Association lowered the 140/90mm Hg figures to 130/80mm Hg, meaning many people whose blood pressure was previously regarded as raised or elevated should be treated as if their blood pressure is high. This means about 46 per cent of American adults fall into the high blood pressure group. If adopted in the UK, the guideline would add about 7 million people into the numbers with high blood pressure.

A systolic reading from 140-159mm Hg or a diastolic measure of 90-99mm Hg means you have stage 1 hypertension (or stage 2 under the latest US guidelines); in the UK, if systolic pressure is 160mm Hg or higher or diastolic is 100mm Hg or above, you have stage 2 hypertension. If you have systolic pressure of 180 mmHg or higher, or diastolic pressure of 110 mmHg or higher, you have severe hypertension.

Most people have ‘primary’, or ‘essential’, high blood pressure, which develops on its own over years.  Sometimes high blood pressure is caused by medication or another medical condition. This is called ‘secondary’ hypertension. It usually goes away if the medication is stopped or the condition causing it is treated.

There’s a lot you can do yourself to reduce your blood pressure and there’s a range of medications that can help control it.

What are the symptoms of high blood pressure?

Generally, there are no symptoms with high blood pressure, though very rarely it may cause such things as headaches, vomiting, blurred vision or nosebleeds. 

‘I had increased frequency and severity of headaches, blurred vision, and sleeplessness.’

– response in 2018 HealthUnlocked hypertension survey

In a 2018 survey of people with hypertension using the HealthUnlocked website, 71 per cent had their high blood pressure found during routine health checks when they had no symptoms of any kind. Most were found during a doctor visit, but workplace, gym and home testing also featured. In the other 29 per cent, most had blood pressure checked as part of investigating or monitoring of another illness.  

“At the gym my personal trainer decided to check my BP and it read 205/95 …”

– response in 2018 HealthUnlocked hypertension survey

If untreated, high blood pressure will eventually cause damage in your body that could be fatal. According to the UK National Institute for Health and Care Excellence, for example, even in people with blood pressure in the ‘normal’ range, each 2 mmHg rise in systolic pressure is linked to a 7% increased risk of death from coronary heart disease and a 10% increase in risk of death from stroke.  

The only way to know if you have high blood pressure is to have it measured and checked periodically.

How is high blood pressure diagnosed?

High blood pressure is diagnosed by measuring the pressure with a sphygmomanometer – usually just called a blood pressure monitor, meter or gauge. Having your blood pressure reading taken is simple and painless and takes only a few minutes.

There are various types of blood pressure monitor, from traditional manual equipment – stethoscope, inflatable arm cuff, pump to inflate the cuff and a dial that shows the readings – to quite sophisticated digital kit that automates much of the test and readouts. The manual equipment is usually regarded as most accurate, but users require training. Digital equipment is often used for screening or initial testing and is typical for home monitoring. 

Generally, with any blood pressure device, a cuff will be placed round your upper arm and inflated to restrict the blood flow in your arm for a few seconds. The cuff pressure is then slowly released, and the systolic and diastolic blood pressures are recorded as normal blood flow resumes.

You can usually get the results there and then from the health professional doing the check, or from a digital readout. A high reading, however, will not immediately bring a diagnosis of hypertension. 

Your blood pressure naturally changes throughout the day and various things can affect it. Blood pressure is usually lowest when you are asleep. It starts to rise in the early hours and will fluctuate somewhat throughout the day depending on what you are doing – it’s not unusual to have temporary changes of between 5mm Hg and 40mm Hg.  

“Understand what it is, what are some of the causes and what you can do to alleviate problems. Check out the medication – read the accompanying paperwork and make certain you don’t suffer side effects”

– response in 2018 HealthUnlocked hypertension survey

Blood pressure typically goes up when you do physical activity or are excited or nervous. Smoking, alcohol and caffeine can all cause temporary blood pressure increases, as does having a full bladder. Temperature can also affect blood pressure – it tends to rise when we are cold. Some people get raised blood pressure because they find visiting the doctor stressful – this is known as ‘white coat hypertension’.

One high reading, therefore, is not enough to diagnose hypertension. If your initial blood pressure reading is raised, your doctor will usually take several readings at three or more separate appointments and might ask you to record your blood pressure at home and at work with a home monitor. You may be offered ambulatory blood pressure monitoring (ABPM), using a device you can wear for 24 hours that will monitor your blood pressure throughout the period. This should give an accurate picture of your usual blood pressure and how it fluctuates on an average day. 

If the readings show that your blood pressure is consistently at or over 140/90mm Hg (or 130/80 under the latest US guideline), you will be deemed to have hypertension.

Both numbers matter in a blood pressure reading and you may have hypertension if either is raised. 

In people older than 60, the systolic reading is often found to be high while diastolic pressure is normal. This is referred to as isolated systolic hypertension and is known to carry increased risk for strokes and heart attacks. 

What causes high blood pressure?

The cause of high blood pressure isn’t known in more than 9 out of 10 cases. But various things increase your risk of having it.

Some factors that can raise your chances of high blood pressure include:

  • age – the risk of hypertension increases as you grow older; while up to 46 per cent of American adults have high blood pressure overall, the figure rises to 65 per cent among the over 60s
  • a family history of high blood pressure increases risk – hypertension tends to run in families
  • having a diet high in salt or sodium – this causes you to retain fluids, which raises blood pressure 
  • not doing enough exercise
  • being overweight 
  • being of African or Caribbean origin – hypertension is more common in black people than others and tends to develop earlier
  • smoking – using tobacco temporarily raises your blood pressure but can also damage blood vessels and cause arteries to narrow bringing a long-term rise in your blood pressure. 
  • drinking alcohol heavily

“Sodium is hidden in nearly everything we consume. It has a tremendously negative effect on blood pressure and is also easily avoidable. You just need to pay closer attention to what you eat before you eat it.”

– response in 2018 HealthUnlocked hypertension survey

A proportion of people – up to 10% – have high blood pressure because of a known cause. This is called secondary hypertension.

Things that can cause secondary hypertension include:

  • kidney disease
  • diabetes
  • hormonal conditions, such as thyroid problems 
  • conditions such as lupus, that damage body tissue
  • nonsteroidal anti-inflammatory drugs (NSAIDs), which are painkillers such as ibuprofen
  • recreational drugs, such as amphetamines and cocaine
  • oral contraceptives
  • some herbal supplements, such as arnica or liquorice

What are the effects of high blood pressure?

High blood pressure can damage your blood vessels and organs and cause a range of conditions, many of which are life-threatening. The higher the pressure and the longer it is high, the greater the damage. 

Sustained high blood pressure can lead to:

  • thickening and hardening of your arteries – known as atherosclerosis, this can bring clots and blockages (thrombosis) and lead to strokes and heart attacks
  • strokes – where the blood supply to the brain is interrupted. High blood pressure is blamed for about half of the most common type of stroke (ischaemic stroke)
  • heart attacks – where blood supply to part of the heart is blocked
  • aneurysms – where weakness in a blood vessel forms a bulge. If an aneurysm bursts it can be life-threatening.
  • heart failure – where your heart can no longer pump enough blood to fully meet your body’s needs
  • kidney disease – the hypertension damages small blood vessels in your kidneys and stops them working normally
  • damaged eyesight or sight loss – caused by damage to blood vessels in your eyes
  • dementia – high blood pressure, especially in mid-life, is a major risk factor for developing dementia in later life

‘Hypertension if untreated leads to more serious conditions like strokes, heart attacks, and ultimately death to name a few. Remember that when you don’t feel like keeping up treatments/care.’

– response in 2018 HealthUnlocked hypertension survey


High blood pressure can cause complications in pregnancy. If you are pregnant your blood pressure should be checked regularly even if it isn’t usually high. It’s possible to get pregnancy-induced hypertension, which can lead to pre-eclampsia. This can cause problems and in severe cases can provoke seizures that are potentially fatal to mother and baby.

Women who have high blood pressure before they become pregnant have a higher risk of miscarriage, premature births, or stillbirth. 

What’s the treatment for high blood pressure?

The precise treatment you get for high blood pressure depends on things like your age, general level of health, other conditions you are being treated for, and the level of your high blood pressure. In particular, your risk for cardiovascular problems such as heart attack or stroke, or your risk of kidney disease, will influence how you are treated. 

Treatment for hypertension is through lifestyle changes or medication, or most often a combination of the two.

‘Lose weight, be more active, try not to become too stressed and take your pills if prescribed.’

– response in 2018 HealthUnlocked hypertension survey

Everyone – with or without hypertension – can make changes in their daily lives that will help to lower their blood pressure – and in general terms, the lower it is the better (extremely low pressure, below 90/60mm Hg, may cause problems but rarely needs treatment). 

For some people with hypertension, lifestyle changes are all that is needed to lower the pressure and get it under control.

Life changes

There’s lots you can do to improve your blood pressure. Steps you can take include: 

  • cut salt intake to below 6g a day – equivalent to a teaspoon. Most of the salt you eat is in processed and preserved foods, so you need to read labels to know what to cut out. A teaspoon of salt contains 2.3g of sodium, which is the daily recommended maximum. Aiming for 1.5g or less is better for your blood pressure 
  • eat a balanced low-fat diet with plenty of fresh fruit and vegetables. One diet designed to combat high blood pressure is the DASH eating plan – it stands for Dietary Approaches to Stop Hypertension and is recommended by US health authorities 
  • be more active – regular exercise makes your heart stronger, so it can pump blood more easily. If your heart uses less effort, there is less force on your blood vessels and your blood pressure decreases. Being physically active can also help you lose weight. Aerobic exercise such as brisk walking, swimming or cycling is good for the heart and blood vessels   
  • cut down on alcohol – research has shown that regular drinking above recommended levels raises your risk of high blood pressure 
  • if you’re overweight, try to get down to a healthy weight – in general, your blood pressure goes up with your weight. Losing weight can lower your blood pressure and the effect is biggest in overweight people with hypertension.
  • drink less caffeine – in coffee, tea, cola or energy drinks. Caffeine causes a small temporary rise in blood pressure in healthy people. However, its effects are more marked in people who have raised blood pressure – and if your numbers are already high, you don’t want to make them higher
  • stop smoking – using tobacco increases your heart rate and blood pressure. It also hardens and narrows your arteries, and makes blood clots more likely, adding to your risk of a stroke or heart attack
  • get at least six hours sleep a night – research shows that sleeping less than six hours might lead to increased blood pressure. Sleep helps you regulate stress hormones. Too little sleep may mean levels of stress hormones in your body stay high and cause a permanent increase in your blood pressure

‘I’ve changed my lifestyle; lost a lot of weight and started exercising and within months was able to come off medication.’

– response in 2018 HealthUnlocked hypertension survey


A variety of medicines can be used to lower blood pressure. Often, you’ll need to take more than one – a combination is usually needed to get the best treatment with the least side effects.

‘Eventually I settled on a medicine to control my high blood pressure. That took 4 or 5 different medicines.’

– response in 2018 HealthUnlocked hypertension survey

Some people need medication for the rest of their lives, others may be able to reduce or stop treatment if their blood pressure stays at a reasonable level. 

As with all medicines, it’s important to take blood pressure medication exactly as directed to ensure it is effective. As high blood pressure usually has no symptoms, you may not notice any difference when you start the medicine. But you should soon see your blood pressure numbers going down as your medication takes effect.

Medicines for high blood pressure can have side effects, though many people don’t get any. Common side effects include drowsiness, kidney pain, swollen feet, a cough, a rash, and feeling dizzy. If you notice any side effects, you should talk to your doctor, nurse or pharmacist for advice. Because of the variety of medicines available for hypertension, your doctor might be able to change your drugs to stop any side effects.

In all cases you should check that any over-the-counter medicines or supplements – including ‘natural’ remedies – you intend to take are safe to use with your blood pressure medication; some have the potential for dangerous interactions.

Medicines commonly used to combat high blood pressure include:

  • ACE inhibitors – angiotensin-converting enzyme inhibitors
  • ARBs – angiotensin-II receptor blockers
  • Calcium channel blockers
  • Diuretics – thiazide diuretics, often referred to as ‘water pills’
  • Beta-blockers

Other classes of drug that are sometimes used for high blood pressure include alpha blockers, alpha-beta blockers, vasodilators, central-acting agents, and aldosterone antagonists.

Living with high blood pressure

Being diagnosed with high blood pressure doesn’t mean you can’t continue to live life to the full. In fact, by following a healthier lifestyle you might find you enjoy life more. 

The main things you need to do are make the day-to-day changes in how you live that will curb your high blood pressure and take your medication as directed. Your medicines may need adjusting to get the most effective treatment or to deal with side effects.

In a 2018 HealthUnlocked survey among people with hypertension, almost half of respondents said having to take medication or deal with its side effects was what had most impact on their lives. And 16 per cent said the condition had no untoward impact.

“It hasn’t impacted on my life other than more consciously thinking about leading a more healthy lifestyle, for instance losing excess weight, eating more healthy foods and trying to be more active”

– response in 2018 HealthUnlocked hypertension survey

Some people find that having a home blood pressure monitor helps them track the condition and can show what works for them and what doesn’t. It’s encouraging to see your numbers falling over time, but a home monitor will also alert you if the pressure is going the wrong way. Your blood pressure records can give your healthcare team a good picture of your condition and how it is responding to treatment. 

There are various things you need to consider when you have high blood pressure. 

Eating out can be problematic as restaurant food often contains high levels of salt – it’s worth asking about this when you book or before you order. 

‘I’ve had to withdraw from eating out with friends for hypertension control purposes.’

– response in 2018 HealthUnlocked hypertension survey

Driving for personal reasons is fine for most people with high blood pressure unless their medicine causes side effects that make it dangerous. People who drive passenger vehicles or heavy goods vehicles usually can’t do so until their blood pressure is under control. Your doctor or driver licensing agency should be able to advise you.

Travel, including flying, is usually OK unless your blood pressure is very high or unstable. If you have any concerns, check with your doctor before you book anything. 

Insurance for things like travel, life, health and so on might be a little more expensive or harder to find, but in general you do need to declare your high blood pressure to insurers or they might not pay out when you claim.

Some people have relationship problems, either because they become anxious or depressed at having a heart condition, or because hypertension or its medication interferes with their sex life. Some men find they get erectile dysfunction and some women find sex becomes uncomfortable or even painful. These problems can usually be resolved, so talk to your doctor.


Talking to others with high blood pressure can be a great source of advice, information and reassurance. There are numerous online forums, communities, Facebook groups and so forth for people with high blood pressure or heart conditions in general.

Knowing as much as you can about your condition will help you understand and manage it. There are many good sources of information for people with hypertension. You could try:

If you are thinking of getting a home monitor, there’s information on choosing and using these at:

Resources consulted in the preparation of this information

Sources listed here were all accessed in February 2018

US National Library of Medicine

UK National Institute for Health and Clinical Excellence

Blood Pressure UK

The American Heart Association

Mayo Clinic

World Health Organization

British Heart Foundation

US National Center for Biotechnology Information

PLOS Medicine

US Centers for Disease Control and Prevention

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