The small arteries of the brain are sensitive to elevations in blood pressure, and long-term hypertension carries the risk of injury to these small vessels, impairing blood flow and resulting in damage to or atrophy of brain tissue. As such, high blood pressure is hazardous to the brain, contributing to the development of vascular dementia, Alzheimer’s Disease , and cognitive impairment: 
High diastolic blood pressure at age 50 predicts poorer cognitive function at age 70. 
Even in younger subjects - 40 and under - higher blood pressure correlates with poorer cognitive performance.
An MRI study determined that higher systolic blood pressure is associated with white matter lesions – a type of damage to brain tissue that arises due to poor circulation and poses risk for dementia. 
According to long-term (20-year) studies, the risk of Alzheimer’s and other forms of dementia is more than doubled if systolic blood pressure is in or above the range of 140-160 mmHg. 
Most cognitive impairment is not age-related, it is lifestyle-related.
Over many years, the Western diet combined with high blood pressure inflicts a great deal of damage on the brain’s delicate small vessels. Keeping your blood pressure in the favorable range is an important step toward maintaining your brain function as you age.
Dr. Fuhrman’s strategies for healthy blood pressure levels:
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