Hypertension (or high blood pressure) is a common disorder in which the pressure of blood in the arteries is persistently raised.

Hypertension is classified as either primary or secondary; in most cases it is primary which means there is no clear underlying medical cause whereas secondary hypertension is caused by other medical conditions that affect the heart, kidneys, arteries or endocrine system.

If left untreated hypertension can increase the risk of stroke, heart failure, heart attack, kidney failure or vascular disease.