8 facts about blood pressure you need to know


Dr Roger Henderson brings us up to speed

By Dr Roger Henderson

High blood pressure is a major cause of heart attack and stroke, but most of us don’t even know the facts. Here, NetDoctor GP Dr Roger Henderson gives the low-down on everything you need to know about blood pressure.

  1. Blood pressure keeps you alive

Our heart is a small but very powerful pump that beats steadily and pumps about five litres of blood around our body every single minute of the day and night. To maintain this there has to be a certain degree of pressure in our circulation to keep the blood flowing, and this is what is meant by our blood pressure.

Blood pressure is divided into the pressure that occurs when our heart contracts or squeezes – known as the systolic pressure – and the pressure present when the heart relaxes is called the diastolic pressure. These pressures are what your doctor measures when they check your blood pressure and the figures used are in millimetres of mercury, so a typical reading may be described as 140 / 80 where 140 is the systolic pressure and 80 the diastolic.


  1. It changes throughout the day

Blood pressure varies naturally through the day, increasing with exercise and stress and falling at rest or when asleep. It can also go up just by the process of it being taken by a doctor or nurse – so-called ‘white coat blood pressure’and in these cases buying a blood pressure monitor and taking some readings at home when you are more relaxed can be helpful.

Blood pressure does not usually need to be checked every day or even every week; if you are on medication for high blood pressure and it is stable have it checked every few months, otherwise every few weeks is more than enough. If you have normal blood pressure, checking it a couple of times a year is fine. Most doctors would agree that aiming for a blood pressure of 130/80 or less is acceptable, but if you have diabetes and known heart problems then lower readings are even better.

  1. High blood pressure sometimes just happens…

High blood pressure (also called hypertension) affects many people and is increasingly common as you get older. This usually occurs because the arteries that carry blood around the body become less elastic and more ‘stiff’ with age, but for the vast majority of people there is no obvious cause otherwise – it simply just happens, and this is known as ‘essential’ or ‘primary’ hypertension. In about 10% of cases there is an underlying medical cause for the raised blood pressure, and so this is called ‘secondary’ hypertension. Typical causes in these cases include chronic kidney diseases, problems with the blood supply to the kidneys, chronic alcohol abuse and some hormonal disturbances that affect the kidneys.

  1. …But a variety of factors can trigger it

There are plenty of factors that can trigger high blood pressure, and the main ones include;

  • A family history of high blood pressure
  • Obesity
  • Smoking
  • Too much salt in the diet
  • Lack of exercise
  • Diabetes
  • Kidney diseases


  1. You might not realise you have high blood pressure

One of the big problems with hypertension is that it actually causes very few symptoms in most people. Even apparently very fit people can have high blood pressure without realising it, but in severe cases there may be nosebleeds, headaches, sleeping difficulties, confusion and breathing problems.


If hypertension is left untreated, or you are unaware you have it then your chances of having a heart attack or stroke are greatly increased. By treating it, complications can be avoided and a normal life span can be reasonably expected. Typical complications apart from strokes and heart attacks include heart failure, where the heart gradually loses its ability to pump blood around the body effectively, kidney failure, eye damage and weakening and expansion of the main artery (the aorta) of the body as it passes through the chest or abdomen. This can cause it to suddenly rupture with possible fatal consequences.

  1. But there are things you can do to reduce it

Fortunately you can help yourself if you are diagnosed with high blood pressure and one of the commonest initial treatments is not with drugs but by simple lifestyle changes and in at least a quarter of people this will be enough to bring their blood pressure down to normal levels. These include:

  • Stopping smoking. The biggest single thing you can do to improve your health and blood pressure in general is to give up smoking. Smoking doubles your risk of getting heart disease and trebles your chance of dying before reaching retirement age. If you find it difficult to stop, ask your doctor about treatments that can help you here.
  • Reducing your weight.Every kilogram of weight lost will help to reduce your blood pressure, and the simple advice is to avoid foods rich in saturated fats and eat more white meat, oily fish, fresh fruit and vegetables as well as increasing your fibre intake.
  • Cut back on alcohol. Too much alcohol will push your blood pressure up, so aim to keep intake to below the recommended limits of 3 units a day for men and 2 for women, where one unit is equivalent to half a pint of beer, a glass of wine or a single measure of spirits.
  • Trying to take regular exercise. This need not be strenuous or involve joining a gym but can be as simple as walking briskly for 20 to 30 minutes three to four times a week.
  • Do not add salt to your food, and try to avoid eating salty, processed foods.

Even if these simple measures alone do not bring your high blood pressure down completely, they will still help to reduce the number of tablets you may need to take.

  1. There are many medicines to treat hypertension

There are many highly effective drugs for hypertension that can be used in low doses with few if any side effects. Treatment is tailored to each person, with the commonest types used being diuretics (‘water tablets’), beta-blockers, ACE inhibitors and calcium antagonists. If you are pregnant, or intending to have a baby, always let your doctor know since some drugs are more suitable than others in such cases, and your doctor will want to keep a closer eye on you.

  1. You don’t necessarily need a home monitor

Modern home blood pressure monitors are very cheap and reliable but don’t automatically rush out and buy one if you know your blood pressure is normal– you can get this checked in your doctors surgery as many surgeries now have blood pressure machines in their waiting rooms that you can use.

However, if you have occasionally raised blood pressure readings or known hypertension these can be helpful to confirm treatment is working or that no treatment is needed and taking your own blood pressure when relaxed at home is often a more reliable reading than if you are anxious at your doctors. But do not become obsessed about checking it as this can put your blood pressure up!


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