Making sure you get an accurate reading from your blood pressure monitor.

A good way of ensuring that you are getting an accurate set of readings from your clinically validated home blood pressure monitor is to follow the guidance of the European Society of Hypertension.  These are simple, and, if you have been wondering if you are just suffering from “white coat” hypertension or are indeed in need of a lifestyle change then this is a good an accurate approach that will also be useful for your doctor.  I am assuming that you are using a clinically validated automatic blood pressure monitor and that you know how to use it.  If not, you can gets advice on purchasing a validated monitor and using it at www.expertsinbloodpressure.co.uk. 

The idea behind the European Society Guideline is to produce a number of blood pressure readings over a seven day period which then allows an average to be taken – giving a better idea of what your actual blood pressure is that when a single measurement is taken in a surgery, at the pharmacist or at home.

Choose a time, both in the morning and the evening, when you know you are likely to be able to take the time to relax and take your blood pressure.  These time do not have to be exact but can be in a “window”, so for instance between 7am and 9am and then between 7pm and 9pm.  If your blood pressure monitor has a memory then great, but if not – and you might want to do this anyway, make sure you have a pen and piece of paper ready.

Every day for 7 days, take your blood pressure twice in the morning and twice in the evening – noting down the results – remember to make sure you are relaxed, using a clinically validated monitor and following the manufacturer’s instructions.  At the end of the week your readings may look something like this:

	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
Morning	142/88	145/90	140/90	132/82	145/90	140/90	132/82
	137/85	140/87	132/78	140/78	140/87	132/78	140/78
Afternoon	140/86	138/84	133/76	128/76	138/84	133/76	128/76
	138/82	135/80	135/81	129/78	135/80	135/81	129/78

You can now start to work out what your average blood pressure is.  First, disregard the readings you took on the first day.

	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
Morning	142/88	145/90	140/90	132/82	145/90	140/90	132/82
	137/85	140/87	132/78	140/78	140/87	132/78	140/78
Afternoon	140/86	138/84	133/76	128/76	138/84	133/76	128/76
	138/82	135/80	135/81	129/78	135/80	135/81	129/78

You now have a total of 24 reading that you have token at specific times through the week.  Using these numbers you can get an average of your blood pressure in the morning, in the evening and as a whole.  If you are taking medication for your blood pressure, it is worth noting down when you take it.

For my readings I can calculate the following.  The average morning reading was 138/84, the average evening reading was 133/79 and the average for the whole week was 135/81.  This will be a reading that is more accurate than a one off taken in the week and will allow your GP and yourself to get a much better picture of your blood pressure.

Your GP or clinician might want you to have a 24hr ABPM test, but may well be satisfied with these figures.  And if you do have white coat hypertension with high readings when you visit the surgery, this approach will also show that.