The tricky thing about detecting high blood pressure is it doesn’t have many symptoms – yet if it goes unnoticed it can result in some serious problems (see box), even death.
Around a billion people in the world have high blood pressure – yet although this means about one in four adults have it, many of them don’t even know it.
This means that nearly 16 million people in the UK are likely to have what’s clinically known as hypertension but of them, around 7 million don’t do anything about it because they don’t realise, according to the British Heart Foundation.
Don’t be one of them.
Many GP surgeries have a free blood pressure measuring kit (sphygmomanometer) that you can use yourself, painlessly and in about two minutes. But what do the numbers mean?
When your heart pumps, it contracts and relaxes in turn. A sphygmomanometer will give you two numbers – the top one (systolic) is the pressure in your arteries as your heart contracts and forces the blood around the body; the bottom one (diastolic) is the pressure in your arteries when it relaxes between beats.
The difference between the two numbers is your pulse pressure, and ideally this should not be greater than 40; however if the difference isn’t that great but both numbers are high, that’s also unhealthy.
An ideal blood pressure reading would be 120/80 Hg, and a reading of more than 140/90 Hg should sound alarm bells.
So what causes high blood pressure, and what can you do about it?
We still don’t know what the exact cause is for hypertension – and there may be no single reason. We do know it is more common in older people and people of African and South Asian descent, and there may be a genetic factor, too.
But it is widely agreed that the usual culprits don’t help – smoking, too much alcohol, too much salt in the diet, being overweight, not exercising enough, lack of sleep, not enough fruit and vegetables.
Some people may have another medical condition that has an effect on blood pressure, for example a kidney problem, which if treated could lower your BP by itself.
Sometimes a healthy diet, plenty of exercise and stopping smoking won’t be enough to lower your blood pressure. You may have high cholesterol, for instance, which causes atherosclerosis (thickening of the arteries) and sometimes this is nothing to do with diet or lifestyle – it’s just bad luck. Statins are commonly taken to treat high cholesterol, and this could solve your high pressure problem.
There are lots of medications, and the four most common types are:
The chemical angiotensin II narrows blood vessels, raising BP. It also makes your body retain water, which will have a similar effect. ACE inhibitors reduce the amount of the chemical, relaxing the blood vessels and reducing how much water your body retains.
Angiotensin receptor blockers
Work in the same way as ACE inhibitors, prescribed according to patient response.
Calcium channel blockers
A build-up of calcium in the blood can also narrow the arteries – these drugs will reduce the amount in your body.
Otherwise known as water tablets, they increase the need to pass water by working on the kidneys to get more salt out of the body. Too much salt causes extra fluid to build up in the blood vessels, raising the pressure. Diuretics help to flush it out.
We’re all different, and respond to different medication in different ways. You will need to take note of certain foods that should be avoided when on particular medicines, but your doctor will advise you of all this.
A reading of 90/60 Hg or lower could be considered low blood pressure – but this is not usually a cause for concern unless you start feeling dizzy. Treatment is rarely required.