Memory problems may be linked with reduced blood flow to the brain caused by high blood pressure.
Previous research has linked high blood pressure to small and subtle impairments in mental ability, such as memory problems. This has been taken a stage further by researchers at the University of Pittsburgh who ran brain scans on volunteers during memory tests.

They looked at two groups - those with normal blood pressure and those with high blood pressure. The scans revealed that there was reduced blood flow to the brain during the memory tests in those with elevated blood pressure. They also did a little worse on the memory tests which included everyday tasks such as remembering a phone number for long enough to dial it. This 'running memory' often gets somewhat worse with age. So it's as if high blood pressure adds a few years to your mental age - another good reason for keeping it under control.