Hypertension damages the brain very early on, even before measurable blood pressure rises. Research in mice has shown that key brain cells associated with blood vessels, signalling and myelin maintenance begin to age prematurely and fail as early as three days after the induction of hypertension, that is, before blood pressure rises. After 42 days, these changes worsen and are associated with cognitive decline. The endothelial cells of the vascular lining lose strength, leading to damage of the blood-brain barrier. These damages are similar to those seen in Alzheimer's disease and other cognitive disorders. The drug losartan was able to partially reverse some of this early damage in mice. Patients with hypertension have a 1.2- to 1.5-fold higher risk of developing cognitive impairment compared with people without hypertension[1][3][5].