India, Sept. 29 -- Hypertension's cruelty is that it asks nothing of you until it takes everything. Most people feel no pain or symptoms, though a small minority get warning signs like headaches or dizziness. For years, it slowly damages the heart, brain and kidneys, then, without warning, speaks all at once with a stroke, a heart attack, or failed kidneys. A parent driving to work may struggle to speak, walk, or recognise loved ones. Survivors call stroke worse than death; families ask too late how this happened when all seemed normal.

Often, the answer is a number no one thought to check: blood pressure. High blood pressure is quietly at work for years before it declares itself. This World Heart Day, observed under the theme "Don't Mis...