With tests that track the brain's activity in response to specific tasks, researchers determined that people with high blood pressure get less blood to the brain than people with normal blood pressure. "The reduced blood supply reduces the brain's ability to perform needed tasks, such as remembering an unfamiliar phone number," said J. Richard Jennings, Ph.D., study author and professor of psychiatry and psychology at the University of Pittsburgh in Pennsylvania.
Since memory does "lose its edge" as a person ages, Jennings said that one way to look at high blood pressure is to think of it as adding a few years to mental age.
"For several years, researchers have observed that people with high blood pressure seemed to perform a little differently on mental tasks. These were subtle differences, almost the sort of thing that would suggest the test subject was not paying good attention," Jennings said. "But those reports were anecdotal observations with no physiological data to back them up."
When brain imaging technology advanced to the point where scans could detect the metabolic activity of the brain during certain tasks, Jennings' team decided to look for proof that high blood pressure did impair memory.
High blood pressure is defined as a systolic pressure (the top number in a blood pressure reading) of 140 millimeters of mercury (mmHg) or higher and/or a diastolic pressure (bottom number) of 90 mmHg or higher.
They recruited 59 volunteers, average age 60, with blood pressure readings below 140/90 mmHg, and 37 volunteers, average age 61, with hypertension, defined as systolic pressure of 140 mmHg or greater or diastolic pressure of 90 mmHg or greate
Contact: Carole Bullock
American Heart Association