Hypotension is abnormally low blood pressure — generally below 90/60 mmHg — the mirror image of hypertension and, when symptomatic, just as disruptive. Insufficient pressure means insufficient perfusion: dizziness on standing (orthostatic hypotension), fainting, blurred vision, and fatigue as the brain and organs go short of blood. Causes range from dehydration, blood loss, and sepsis to heart failure, endocrine failure, and the blood-pressure drugs treating hypertension a little too well. Athletes and the young may run naturally low pressures without any symptoms — hypotension is only a disease when it causes trouble. Treatment targets the cause: fluids, salt, compression stockings, medication review — and, rarely, pressor drugs.