Worldwide, three out of every 10 people have hypertension (high blood pressure); the World Health Organisation has called it the planet’s “number one killer”. Latest figures show 1 billion people have been diagnosed with the condition. But half those people who have high blood pressure are unaware of it and some who are aware do not take any medical action due to access or choice. For World Hypertension Day on 17 May, the theme is Know Your Numbers, with the goal of increasing awareness of high blood pressure.