By Dr David Delvin

THE MYSTERIES OF BLOOD PRESSURE

"What on earth is that blood pressure business all about?" That's what a friend of mine said to me recently - as I was unwrapped the 'BP' cuff off his arm. "What do you mean?" I asked him. "Well, I want to know why you doctors keep taking our blood pressure. What actually is blood pressure, anyway? And does it really matter if it's high or low?"

I realised that a lot of people shared his puzzlement about the whole subject. So this month, I am going to explain what 'BP' is all about....

WHAT IS BLOOD PRESSURE?

Blood pressure is the pressure inside your arteries; these are the little tubes that carry blood from your heart to the rest of your body.

It has no connection at all with your VEINS; these are the blue tubes, which you can probably see just under your skin (and has no connection with your BLOOD COUNT either). If you want to feel an artery, just put your fingertips on your pulse at your wrist. That throbbing which you can feel is an artery beating.

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WHY DOES BLOOD PRESSURE MATTER?

A very long time ago, doctors realised that if people had high blood pressure, then they were much likely to die of certain things - like heart attacks and strokes.

Furthermore, health professionals found that if a woman's BP went up during pregnancy, she was far more likely to run into serious complications and that her baby was at increased risk too.

Later on, it became clear that if high blood pressure could be lowered to normal levels, then the danger of nasty things happening went away.

So that is why doctors, nurses and midwives (especially midwives!) spend so much time taking people's blood pressures. It is because they know that high BP should be spotted and treated promptly, in order to give people a chance of a healthier and longer life.

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LOW BLOOD PRESSURE 

What about LOW blood pressure? Well, let's get this one out of the way quickly, because compared with high blood pressure, it is not really much of a problem.

Indeed, in the United Kingdom low blood pressure is not considered to be an illness at all. This is a dramatic contrast with the Continent, where many doctors routinely diagnose 'low blood pressure' in their patients.

But in Britain, a low blood pressure is generally considered to be a cause for congratulations, since it means that you are likely to live long and with luck avoid strokes and heart attacks.

So you won't find many British doctors who are willing

:
(a) To recognise that low blood pressure exists as a disorder or
(b) To treat it with drugs to make the pressure higher.

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MEASURING BLOOD PRESSURE 

How is blood pressure measured? Back in the 19th century, researchers made a simple but vital discovery. If you wrap an inflatable band round a person's upper arm and then pump it up, there will come a point when it stops the blood flowing through the arteries. And at that moment, the pressure in the inflatable 'cuff' is same as the pressure in the arteries.

So, all they had to do was to connect a measuring device to the inflatable cuff and they would be able to tell what the blood pressure was.

Traditionally, the measuring device has been that oblong box with a column of mercury in it, which you still see on many doctors' desks. Later, scientists found other ways of measuring the pressure, for instance, electronic devices but for most purposes the old-fashioned mercury device still serves pretty well.

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WHAT DO THE TWO FIGURES MEAN?

If you have had your BP taken a few times, you'll probably know that the measurements always consists of two figures. For instance, a health professional may say to you: "Your blood pressure is 140 over 80", this is written as '140/80'

Now what do these two different figures mean? It is like this:

The HIGHER figure is the blood pressure at the moment when the heart is actually in the middle of the beat

The LOWER figure is the blood pressure IN BETWEEN beats.

The higher figure is called "the systolic" and the lower figure is called the "the diastolic". Both of them are important. But the higher (systolic) figure is more easily affected by things like whether you are a bit worried or upset at that particular moment.

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WHAT SHOULD YOUR BLOOD PRESSURE BE?

Now let us bear in mind that high blood pressure is a warning sign of potential trouble (like strokes or heart attacks). So how high is "high"? In other words, what should your BP be?

Until quite recent years, doctors were fairly happy if your lower figure (your diastolic) was 100 or less. As for the higher figure (the systolic), they believed that it should be '100 plus your age'. This was because of the well-known fact that blood pressure increases as you get older.

So the general idea was that for a young lad of 20, a systolic BP of 120 was ok. And for a person of 70, then a reading of 170 was OK. This was all very convenient, but it was wrong!

Yes, it is now realised that in folk who are past their 40th birthday, blood pressure shouldn't normally exceed 140 systolic and 90 diastolic (that is 140/90).

If the pressure is regularly above these levels, then there is some increased chance of running into trouble with a heart attack or a stroke. So it is very definite worth trying to keep your BP below these levels as far as possible.

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HAVING YOUR BLOOD PRESSURE TAKEN 

Unfortunately, having your blood pressure taken can be quite an unsettling experience. It is often particularly bothersome for men because males are not as used to it as women are. The average woman has had her BP taken endlessly - from the time she went on the Pill and all through the years when she was having babies!

And alas, if you are the slightest bit unsettled by the experience of having your pressure checked, the inevitable result is that it goes up! So, a chap whose real BP is 130/85 may find that the experience of having that tight band pumped up round his arm can easily push his reading up to 150/90.

Indeed, it has been found that if a doctor in a white coat takes your BP, the reading is likely to be higher than if a nice, soothing nurse takes it! This phenomenon is actually called "White Coat Hypertension". Oh yes, I didn't explain that 'Hypertension' means exactly the same thing as 'high blood pressure'. People often think that 'hypertension' means 'excessive stress', but that's not the case.

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BEING DIAGNOSED AS HYPERTENSIVE

It is important to realise that one can't really make a diagnosis of high blood pressure on one BP reading alone. The pressure varies quite a lot during the course of the day, going down when you are relaxed and going up if you have been rushing or are worried.

So often, the doctor or nurse has to take several readings over a period of weeks before deciding that you definitely do have high blood pressure. Not until this diagnosis has been definitely established do you need treatment.

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TREATMENT

If possible, the first line of treatment should be natural methods. These include:

SLIMMING DOWN - If you are carrying too much weight. People find this difficult, but in fact shedding a stone can often bring your BP down dramatically.

GETTING REGULAR EXERCISE - Taking fairly vigorous exercise about three times a week will also help bring the pressure down.

AVOIDING STRESS - Being mentally relaxed will also help lower the blood pressure. Some authorities claim that meditation or yoga will bring it down significantly.

Other useful natural measures include cutting down on SALT; avoiding SMOKING; and keeping ALCOHOL consumption to modest levels.

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DRUG TREATMENT

However, most people who have high blood pressure do end up taking daily medication for the rest of their lives. It is a nuisance for them, but it could well save them from a stroke or heart failure.

The choice of BP lowering drugs is up to your family doctor or specialist. But please bear in mind that all of the many drugs which are available can (and frequently do) cause side effects. So if you think that you are getting such effects, don't hesitate to ask your GP about changing the pills.

In particular, please be aware that many BP medications can cause impotence. If this occurs, always ask for a change of medication.

There are over 40 different blood pressure pills on the market. They fall into the following categories:

Thiazides - these are usually the first choice in treating hypertension.

Beta-blockers

ACE inhibitors

Calcium channel blockers

Alpha blockers

Angiotensin II receptor antagonists

Whichever type of pill the doctor put you on, it is well worth reading the leaflet that comes with it, to find out a little about the drug and its possible side effects.

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YOUR FUTURE

Even though you have high blood pressure, you can lead a full life and a long one. But please do not omit to take those tablets!

Also, do not forget the simple natural tips, which I have outlined above, like keeping your weight down and getting plenty of exercise. If you neglect these things, then your pills may be fighting a losing battle.

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Q What actually CAUSES high blood pressure?

A I am ashamed to say that in the majority of cases, we still do not know! For a long time, an epidemic of high BP has affected Western people, probably as a result of our poor diet, which 'furs' up our arteries.

In a few cases of high blood pressure, there IS a clear-cut cause (see below).

Q My son age 29, has suddenly developed high blood pressure. Why has this happened?

A In a young person, there is often some clear-cut reason. Very frequently, the cause turns out to be KIDNEY disease, which usually pushes the BP up. 

So your son should very definitely checked out by special hospital tests. If they find a kidney condition, it may be possible to cure it completely.

Q What are the actual SYMPTOMS of raised blood pressure? In other words, how would I know whether I've got it?

A Actually, high blood pressure generally produces NO symptoms. People often think that the raised pressure is causing some symptoms, but this is most unlikely to be true.

So the only way in which you can find out whether you have got raised pressure is to go and have it taken.

Q Should everybody have their BP taken from time to time?

A Yes, very definitely. This is particularly important for people over 50, who should have their BP checked at least once a year.

Q Is blood pressure the same all over the body?

A No it varies from place to place.

Q What actually keeps the blood pressure up in the various parts of the body?

A It is just a combination of 
a) the thrust coming the beat of the heart and;
b) the firmness of the walls of the little tubes through which the blood is pumping.

Q If pressure varies in different parts of the body, why is it always measured in the upper arm?
A Simply for convenience and consistency. Life would get very muddled if we sometimes took it in the leg and sometimes in the wrist.

Q My husband won't take this blood pressure pills. I know this could lay him open to the risk of heart attacks. But are there any other dangers?
A Absolutely, ma'am. Untreated hypertension may cause heart failure, cerebral haemorrhage, kidney trouble and serious eye disease. Please urge him to talk things over with his doctor.

Q I am now 60 and my BP pills are making it difficult for me to get an erection. Would other brands do the same?
A Not at all, sir. Ask your GP to change the brand immediately. Good luck!

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Q People at my golf club keep coughing without their hankies! Could this give me germs?
A Absolutely, sir! I am appalled at the modern habit of coughing all over the place, instead of coughing into a handkerchief or tissue. Many of the public do not seem to know about the old slogan: 'coughs and sneezes spread diseases'

Q My husband is 66 and takes pride in the fact that he has not been to the dentist for 20 years! Is this is sensible?
A No it is NOT, ma'am. He could be laying up all sorts of trouble for himself. Making a regular visit to the dentist is almost as important as having regular EYE check ups.

Q The white of my eye went bright SCARLET last week, but the doctor says it was nothing to worry about and would go away. Is he right?
A Yes, provided that he has examined you. Many older people suddenly get an alarming looking red stain on the white of the eye. This is caused by a 'sub-conjunctival haematoma' which means a harmless little bleed into the white of the eye. It is often provoked by coughing.

Q Is it true that when a person becomes elderly, their GP HAS to visit them regularly?
A No, this is a widespread myth. Doctors are given a small financial inducement for doing occasional medical check-ups on older folk. But your doctor is most unlikely to come and see you UNLESS somebody asks her to.

Q I really am fed up with the 'casual' way and offhand way my doctor has been treating me since I've got older. I'd like to change GP's. Do I have to ask his permission?
A No. You used to have to notify your old GP, but nowadays you DON'T have to. Just find another doctor and ask his practice to take you on.

Q I seem to be going very deaf in one ear. How could I examine my ear to find out if it is wax?
A This would require mirrors, a special instrument and a good deal of contortionism. If you go to the nurse at your local practice, she can tell you in five seconds whether you have got wax or not. Fortunately, it is very easy to treat with eardrops and possibly ear syringing.

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