So the big news this week is that the American Heart Association has just released new guidelines.
What does that have to do with us? Well the UK and European guidelines all look at the same research studies and no doubt they will be updated soon.
The new guidelines define high blood pressure as greater than 130mmHg systolic and 80mmHg diastolic.
This is lower than before but the guidance on labelling and treatment is a little more complicated. Essentially if there are any risk factors such as being older or having diabetes then we should aim to get down into the normal range.
This is supported by the Sprint trial which was published in 2015, which actually suggested lower pressures of down to 120mmHg were better still, but given the fact that trial populations are quite tightly controlled he guideline committee went for a higher target for the general population.
The bottom line is that we should all look at our blood pressure and try to manage our weight, salt intake and exercise to keep the pressure normal. Many people will need medications also to help keep in a normal range and stay hale and hearty for longer!
What does systolic and diastolic mean?
The heart pumps blood every beat – so the systolic blood pressure is the higher number just after the heart contracts, and the lower number is the diastolic pressure which is what the pressure falls too when the heart is relaxing and the valves are closed to prevent blood rushing back to the heart.
The unit is a millimetre of mercury – that’s right – blood pressure was first measured by connecting a column of mercury to the arterial circulation of dogs and horses to see what height it would rise to (Poiseuille, 1828)! They needed a denser and so heavier fluid than water to fit in a column. We still use the units today – there was a push to change to SI units – kilo pascals but it never took off.