High blood pressure: Symptoms & Causes

What is blood pressure?

Blood pressure plays a vital role in the way the heart delivers fresh blood, containing oxygen and nutrients required throughout the body. To get the blood to go that far, fast enough, it has to be under pressure. This pressure is created by the relationship between three things:

• the heart’s pumping action
• the size and stretchiness of the blood vessels
• the thickness of the blood itself

Blood pressure can be compared to a central heating system. Three vital components work together to make the system work: the boiler (heart), the pipes (blood vessels) and the hot water (blood). The radiators are the different organs and parts of the body.

In order for the same amount of heat to be delivered to the farthest away radiator, the boiler has to send the water out under pressure. The size of the boiler will affect this pressure, as will the size of the pipes (or blood vessels).

Blood vessels have a layer of muscle within their walls, which makes them able to widen or narrow depending on how much blood each part of the body requires.

 

What is high blood pressure?

It is normal for blood pressure levels to go up and down throughout the day.  This is why there is a normal range of blood pressures.  If your blood pressure is consistently higher than it should be it is called high blood pressure or hypertension.  There are two main types of high blood pressure:

Essential or primary hypertension: This is the type of high blood pressure that most people have.  With primary hypertension there is apparently no specific disease process involved and there is likely to be no single cause. It is probably a result of a number of factors, some of which we cannot control, such as our age or family history.  Some factors we can control however, such as being overweight, having a high salt intake, having a high alcohol intake and coping with stress.

Secondary hypertension:  So called because the change in blood pressure comes as a result of (or secondary to) a specific disease or defect. This is rare and is caused by conditions such as kidney disease, problems with glands that produce hormones, and congenital problems affecting a blood vessel in the heart or brain.

Why is treating high blood pressure so important?
Over the years, high blood pressure slowly damages the blood vessels, making them narrower and more rigid, so that the heart has to work harder to push the blood through the vessels making your overall blood pressure rise even more.  This can lead to serious problems throughout the body.  These include:

• Strokes
• Angina and heart attacks
• Heart failure
• Kidney failure
• Vision problems and blindness

The good news is that by detecting high blood pressure and treating it, these problems can be prevented.

When should I have it checked? 

Because high blood pressure very rarely has any symptoms, there is nothing to tell us that anything is wrong. However we do know that high blood pressure is more common as we get older and that having it checked regularly is very important. 

All normally healthy people over 16 years should have their blood pressure checked every five years.  This is particularly important if:

 

• Anyone in your family has high blood pressure, as it tends to run in families  
• There is a family history of strokes or heart attacks
• You are of Afro-Caribbean or South East Asian descent
• You are taking the contraceptive pill
• You have diabetes
• You are concerned about your lifestyle – being overweight, excess alcohol or salt intake, high saturated fat diet, lack of exercise
• You go to the doctor with symptoms that could be related to having untreated high blood pressure, such as headaches

If your blood pressure is ever found to be high, it should be checked every year.

The information in this section has been adapted from the CHSS leaflet Living with High Blood Pressure.