What do my numbers really mean?
I have my blood pressure checked fairly regularly. Generally, as long as my doctor doesn’t look worried by the digits he types into my medical records, I’m happy.
Sometimes I might ask what the reading is: “blah blah over blah” he replies cheerily. I nod my head and smile, none the wiser.
I’m familiar with the style of blood pressure readings, and know that there’s a big number ‘over’ a small number, but I wanted to find out what those numbers really mean…
Put simply, blood pressure is the pressure of blood in your arteries - the tubes that carry your blood from your heart to your brain and the rest of your body. You need a certain amount of pressure to get the blood around your body.
Your heart pumps in a regular rhythm squeezing oxygen-rich blood out of the big main artery – the aorta – which divides and branches into smaller and smaller vessels, nourishing every organ and tissue in the body.
The pressure of blood flowing through your arteries varies according to whether the heart is pumping or relaxing. Each time your heart pumps it contracts and blood is squeezed out, it creates a surge of pressure in the arteries. It’s this peak in pressure against the inside walls of your arteries that gives the top reading, which in medical terms is called your ‘systolic’ pressure.
After each beat/pump of your heart it has to relax to refill with blood, and the pressure of blood in your arteries falls, and this is the bottom reading. This is called your ‘diastolic’ pressure.
So, taking these two measurements give a reading of how much pressure your blood places on the inside walls of your arteries. This is blood pressure.
You should have your blood pressure measured so that you know what your target is. If you don’t have heart or circulatory disease, diabetes or kidney disease your target is to have a blood pressure below 140/85mmHg. (mmHg stands for millimetres of mercury, which are the units that are used to measure blood pressure).
However, if you have heart or circulatory disease – including being told you have coronary heart disease, angina, heart attack or stroke, have diabetes or kidney disease then your blood pressure should be below 130/80mmHg.
Ideally though your blood pressure would be quite well below these levels.
Know Your Numbers week starts today. We’ve got lots of booklets and info online about the ways to help your maintain a healthy blood pressure.
