Why is blood pressure important?

High blood pressure is bad for you. The higher your average blood pressure, the greater your risk of suffering a stroke, a heart attack or heart failure.

But your blood pressure goes up and down. You’d expect it to be lower when you’re sipping a cocktail in the Bahamas than when you’re driving to an appointment in London.
So any blood pressure reading is a snapshot – the picture at one moment in time.

That’s why your doctor is unlikely to diagnose ‘hypertension’ (persistently raised blood pressure) on the basis of one reading. The average blood pressure after three readings is a much better guide.

The lower that average reading, the better – unless it’s so low that you get dizzy or faint. As your average blood pressure goes down, so does your risk.

Even a blood pressure of 130/85 mmHg, which you might be quite proud of, is high enough to count towards the metabolic syndrome. Your risk would be significantly lower with an average pressure of 120/80 mmHg.

Both the top figure (systolic) and the bottom figure (diastolic) are important: if either is persistently high, it increases your risk, even if the other is normal.

Over the age of 50, it is the systolic pressure that usually goes on rising with age. ‘Isolated systolic hypertension’, in which only the top figure is high, is common in older people.

You can have a very high blood pressure and feel fine; you can have a normal blood pressure and feel dreadful. The only way to tell what your blood pressure’s up to is to measure it.

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