Blood pressure refers to the pressure which exists within the body’s arteries as blood is pumped around the body by the heart. It is expressed as two numbers e.g.120/80. This is because there are two phases in each heart beat – systole, when the blood is pumped out of the heart, and diastole, when blood returns to the heart. A raised blood pressure is often first identified when seeing the doctor for some other reason, and when the pressure is routinely measured. This is because most cases of hypertension have no symptoms whatsoever.