The brain is dependent on blood flow for everything from oxygen and glucose to micronutrients and the removal of waste products. It has been believed for some time that elevated blood pressure is a major risk factor for vascular cognitive impairment, defined as a range of changes in brain function, from mild to severe, caused by the impaired flow of blood to the brain. After a review of multiple studies, it appears that high blood pressure is a major risk factor for vascular cognitive impairment and is emerging as a potential risk factor for Alzheimer's disease. This is likely to provide impetus for more specific studies in this area. It also may be a wake-up call for those with high blood pressure to work with their healthcare providers to do everything possible to keep their blood pressure within desirable limits for their age. Prevention runs circles around treatment.