High blood pressure: causes and symptoms explained

Many people don’t realise that they have high blood pressure, despite around a third of adults in the UK having it. High blood pressure, medically called hypertension, if left untreated, can increase your chances of developing serious health issues, including strokes and heart attacks. 

That’s why understanding what high blood pressure is and what the symptoms are is so important.

What is high blood pressure?

A healthy blood pressure is usually between 90/60mmHg and 120/80mmHg. For those aged under 80, high blood pressure is considered to be 140/90mmHg or higher and for those aged over 80, 150/90mmHg or higher. The unit of measurement, mmHg, stands for millimetres of mercury and the two numbers refer to two slightly different pressure measurements. 

The higher number is your systolic pressure which is the pressure in your arteries when your heart pumps blood out. The lower number is your diastolic pressure which is the pressure in your arteries when your heart is refilling with blood. 

Everyone’s blood pressure is different and what’s normal for one person may be considered high or low for another. However, it’s generally considered that if your blood pressure is between 120/80mmHg and 140/90mmHg, you are at risk of developing high blood pressure and should take steps to reduce it. 

High blood pressure means that too much pressure is being put on your arteries, which can cause damage. You are at higher risk of developing certain life-threatening conditions if your blood pressure is not reduced. 

What’s the difference between primary and secondary hypertension?

Primary hypertension is the most common type of high blood pressure. It’s where a specific cause isn’t known but it’s thought to be caused by a combination of dietary and lifestyle factors. 

Secondary hypertension is when there’s a specific cause of your high blood pressure. This is a rarer form of high blood pressure, affecting 5-10% of people. In some cases, the cause of secondary hypertension can be treated to reduce your blood pressure. 

Secondary hypertension is more common in those aged between 18 and 40 and can be caused by:

• Adrenal gland disease
• Constriction of the aorta
• Hormonal abnormalities or thyroid abnormalities
• Narrowing of the arteries supplying blood to your kidneys
• Obstructive sleep apnoea
• Side effects of medications (including birth control pills)

What causes high blood pressure?

It isn’t always clear why a person develops high blood pressure but there are factors that increase your risk. These include:

• Being of black African or black Caribbean descent
• Being overweight
• Being over the age of 65
• Being related to someone with high blood pressure

There are also lifestyle factors that increase your risk, such as:

• Consuming too much alcohol, caffeine or salt
• Not eating enough fruit and vegetables
• Not exercising enough
• Not getting enough sleep or having disturbed sleep
• Smoking
• Stress

If you’re at risk of high blood pressure, changing your lifestyle and making healthier choices can reduce your risk of developing it, while if you already have high blood pressure these changes can help lower it. 

What are the symptoms of high blood pressure?

Most people are unaware that they have high blood pressure as it doesn’t have any symptoms unless it’s very severe. This is why regular check-ups with your GP are important, especially if you’re at risk of developing high blood pressure or have a family history of it. 

If your blood pressure is very high, it may cause: 

• Blood in your urine
• Chest pain or difficulty breathing
• Fatigue or confusion
• Irregular heartbeat and pounding in your chest, neck or ears
• Nosebleeds
• Severe headaches or vision problems

Other symptoms related to high blood pressure, some of which can also be caused by stress, include: 

• Blood spots in eyes
• Dizziness
• Facial flushing
• Nervousness
• Sweating
• Trouble sleeping

What are the risks of having high blood pressure?

High blood pressure means there is extra strain being put on your blood vessels, heart and other organs, such as your brain, eyes and kidneys. If your blood pressure is consistently high, it can cause several serious and potentially life-threatening conditions. 

High blood pressure can put you at risk of:

• Aortic aneurysms
• Heart attacks, heart disease and heart failure
• Kidney disease
• Peripheral arterial disease
• Stroke
• Vascular dementia

If you are diagnosed with high blood pressure, taking steps to reduce it even a small amount can help reduce your chances of developing these conditions. 

How is high blood pressure diagnosed?

High blood pressure is diagnosed with a blood pressure test. This is a simple test that can be done by your GP, at some pharmacies or at home if you have a blood pressure monitor. If you do track your blood pressure with an at-home monitor, it’s a good idea to have your monitor checked by your GP to ensure the readings are accurate. 

Your blood pressure can increase or decrease depending on several factors including your age, emotions, medications and level of activity. This means that a single reading can’t identify whether you have high blood pressure. 

If your blood pressure seems high, your GP may suggest follow-up readings at different times. A high blood pressure diagnosis is only given if you get at least three high readings. 

Your GP will also ask you about your medical history and about your lifestyle to determine whether there are any risk factors. They will also ask about your family history to see if you are at higher risk due to genetics. 

You’ll also undergo a physical examination, which may include listening to your heart to check for sounds suggesting problems with your heart or arteries. If your GP suspects that you have high blood pressure, they may recommend other tests, such as an ECG (echocardiogram) to check on the health of your heart. 

How is high blood pressure treated?

If you are diagnosed with high blood pressure, your GP may prescribe drugs to reduce your blood pressure. There are several different types of drugs and your GP will discuss the most appropriate options with you.

Common medications for high blood pressure include:

• ACE inhibitors
• Alpha-blockers
• Angiotensin-2 receptor blockers (ARBs)
• Beta-blockers
• Calcium channel blockers
• Diuretics

If your blood pressure is very high, you may be prescribed more than one drug or given a combination drug to better treat it. 

Once you start treatment for high blood pressure, you will need regular visits to your GP for tests and monitoring until your blood pressure is well-controlled. After this point, you will still need to have your blood pressure checked annually by your GP or practice nurse.

How can you manage high blood pressure?

As well as medications, there are lifestyle changes that can help lower your blood pressure and allow you to better manage it. These include:

• Cutting down on caffeine
• Eating a healthy diet
• Losing weight if you are overweight
• Reducing alcohol intake and quitting smoking
• Reducing the amount of salt in your diet
• Regular aerobic exercise

These lifestyle changes should be maintained for a lifetime to help maintain a healthy blood pressure. Returning to bad habits once you have lowered your blood pressure could see it increase again and put you at risk of complications, such as a stroke and heart attack. 

How do you reduce the risk of developing high blood pressure?

Preventing high blood pressure if you’re at risk of developing it largely comes down to your lifestyle. In most cases, unless there is an underlying condition causing it, high blood pressure can be avoided by leading a healthy lifestyle. 

Try to eat a healthy diet that includes plenty of fruit, vegetables and fibre but limits your salt intake as salt raises your blood pressure. You should also limit how much alcohol you drink, ensuring you don’t exceed 14 units in a week.

Regular exercise is also important for weight management and heart and blood vessel health. So aim to do at least 150 minutes of moderate-intensity aerobic activity every week. 

You should also quit smoking as this can put you at greater risk of a heart attack or stroke.