High Blood Pressure

What is blood pressure?

Blood pressure is the pressure measured within the arteries of the body blood is pumped around your body by your heart.  High blood pressure is common but it very rarely causes any symptoms and so many are unaware that it is there. High blood pressure is very important as if left untreated it increases the risk of a heart attack, stroke and kidney damage. Because it can go unnoticed it is important that adults aged over 40 should have their blood pressure checked at least once every five years. Those with an increased risk of high blood pressure, or borderline measurements should have it checked more often.

How is blood pressure measured?

Blood pressure has traditionally been measured using a sphygmomanometer, a device which consists of a stethoscope, arm cuff, dial, pump and valve. The cuff is placed around your arm and pumped up to restrict the blood flow. The pressure is then slowly released as your pulse is checked using the stethoscope. Most doctors now use digital sphygmomanometers, which measure your pulse using electrical sensors.  To get an accurate blood pressure reading, you should be sitting down and not talking when the reading is taken. 

There are now many devices that can be used at home your chemist will be able to advise on the best types if you need one. These often show lower readings than those taken at your GP or in hospital because of the anxieties these places cause an effect known as white coat hypertension. However, the gold standard for measurement is an ambulatory blood pressure monitor, which takes measurements over 24 hours at home or at work. 

What do the numbers mean?

Blood pressure is measured in millimetres of mercury (mmHg) and every blood pressure reading consists of two numbers, one on top of the other, for example 120/80mmHg or "120 over 80 The top number represents the highest level your blood pressure reaches when your heart beats and pumps blood through your arteries - your systolic blood pressure. The bottom number represents the lowest level your blood pressure reaches as your heart relaxes between beats - your diastolic blood pressure. 

What is high blood pressure (hypertension)?

High blood pressure or hypertension means that your blood pressure is constantly higher than the recommended level. Ideally, your blood pressure reading should be below 120/80mmHg. However, anything under 130/80mmHg is generally considered normal. Generally treatment is started if the measurements are persistently over 140/90mmHg.

What are the causes of high blood pressure?

There is usually no cause for the cause of high blood pressure. There can be many contributing factors though such as:

 - lack of physical activity 

 - being overweight or obese 

 - too much salt in your diet 

 - regularly drinking too much alcohol 

 - not eating enough fruit and vegetables 

 - having a family history of high blood pressure. 

However, high blood pressure is unusual in young people and there can be (rarely) underlying causes such as hormonal problems, kidney problems or arterial problems.

If I have been diagnosed with high blood pressure, what other tests may I need?

Your doctor would normally check your urine for protein and blood, and may arrange blood tests to look at kidney function. Often other tests such as cholesterol checks are done at the same time. In those younger patients with hypertension additional tests may be done to look for rare causes of hypertension which include a chest x-ray, a kidney ultrasound and a 24-hour collection of urine to check adrenaline levels.

How is high blood pressure treated?

Blood pressure can be treated by both lifestyle measures and medications. There are some newer techniques too such as renal artery denervation which seem promising in very difficult to treat hypertension

Lifestyle measures

All patients with high blood pressure should look at lifestyle measures, and eating healthily with a low salt diet, maintaining a healthy weight, taking regular exercise, drinking alcohol in moderation and not smoking are all important.  These are summarised below:

Diet - Cut down on the amount of salt in your food - aim to eat less than less than 6g (0.2oz) of salt a day, which is about a teaspoonful . Eat plenty of fruit and vegetables - aim to eat five 80g portions of fruit and vegetables every day. Eat a low-fat diet that includes lots of fibre

Alcohol - Regularly drinking alcohol above the recommended levels (21 units per week in men and 14 units per week in women) can raise the blood pressure over time. Staying within the recommended levels is the best way to reduce your risk of developing high blood pressure. 

Caffeine - Drinking more than four cups of coffee a day may increase your blood pressure, so this should be reduied.

Weight - Being overweight can raise your blood pressure. Losing weight can make a big difference to  blood pressure and overall health.

Exercise - Regular exercise lowers blood pressure helps to  lose weight. Adults should exercise hour  5 days a week. The activity should make you feel warm and slightly out of breath. 

Smoking - Smoking just adds to the risk of hypertension, and the risk of a heart or lung disease in the future is dramatically increased. =


There is a wide range of blood-pressure-lowering medicines to choose from. You may need to take more than one type of medication and often  a combination of drugs is needed to treat high blood pressure.

ACE inhibitors - Angiotensin-converting enzyme (ACE) inhibitors reduce blood pressure by relaxing your blood vessels. The most common side effect is a persistent dry cough. If side effects become particularly troublesome, a medication that works in a similar way to ACE inhibitors, known as an angiotensin-2 receptor antagonist, may be recommended.

Calcium channel blockers - Calcium channel blockers keep calcium from entering the muscle cells of the heart and blood vessels. This widens your arteries and reduces your blood pressure. 

Diuretics - diuretics or 'water tablets' work by flushing excess water and salt from the body through urine.

Beta-blockers - Beta-blockers work by making your heart beat more slowly and with less force, thereby reducing blood pressure. Beta-blockers used to be a popular treatment for high blood pressure but now they only tend to be used less now as it is recognised that they  are considered to be less effective than the other medications (although may be used to treat hypertension if there are also angina symptoms)

Alpha-blockers -  Alpha-blockers work by relaxing your blood vessels, making it much easier for blood to flow through them.

Renal artery denervation

This is a new technique where the nerves found within the arteries to both kidneys are cauterised or 'ablated' by a catheter passed up from the groin (in a similar way to an angiogram). By interrupting these nerves blood pressure can be reduced. This is a new procedure in its early stages but the initial results are very promising. I have now performed this procedure at the Essex Cardiothoracic Centre in collaboration with my colleague Dr Nicholas Robinson. Only very difficult cases will be treated initially but it may well become more common with time.

Every effort has been made to ensure that the information on this website is up-to-date and accurate. However, it is intended to serve as a guide only. Symptoms may vary and if you have any medical concerns you should always consult a healthcare professional.