High Blood Pressure Causes Memory Lapse?

Short-Term Memory Slightly Worse in Those with Hypertension

From the WebMD Archives

Sept. 23, 2003 -- There's more evidence that taking measures to prevent heart disease and stroke may benefit your mind as well as your body. A new study suggests that some short-term memory lapses often attributed to aging may actually result from having high blood pressure.

"It's not that people with high blood pressure suddenly lose their memory, but they are slightly inferior in doing tasks that require them to pay attention and remember things for brief periods compared to those with normal blood pressure readings," says researcher J. Richard Jennings, PhD, of the University of Pittsburgh.

While these differences are subtle and involve tasks such as recalling an unfamiliar phone number, Jennings says they are equivalent to five to 10 years of aging.

"It's like you lose your edge in short-term memory a little bit with high blood pressure," he tells WebMD. However, his research gives no indication that hypertension affects long-term memory.

In July, a study estimated that nearly one in three American adults has high blood pressure, defined as having a systolic pressure (top number-or the pressure that the heart must pump against to push blood through blood vessels)) of 140 millimeters of mercury (mmHG) or higher, and a diastolic pressure (lower number- or the resting pressure that the heart has in between heart beats) of 90 mmHg. Previously, hypertension was thought to affect one in five adults.

Recently, federal blood pressure guidelines included a new classification -- a "prehypertension" stage that includes the one in four adults whose systolic blood pressure falls between 120 and 139 or whose diastolic blood pressure is between 80 and 89. Untreated, these people will likely develop high blood pressure.

Jennings' study, presented Monday at the American Heart Association's annual High Blood Pressure Research Conference, tracked 59 people with normal blood pressure readings and 37 others diagnosed with hypertension.

Using sophisticated tests, his team measured their brain activity in various memory tests. The study volunteers also had ultrasound imaging scans to measure blood supply to their brains.

These scans showed that some hypertensive patients had less blood reaching their brains. "But even when blood flow was normal, brain neurons didn't activate as rapidly and as much as they should in the people with high blood pressure," Jennings tells WebMD.

This "slower" brain activity -- which may be attributed to so-called "senior moments" characterized by occasional memory lapses that occur after age 50 -- was noted at similar levels in all the hypertensive patients he evaluated, no matter their age. The participants were between ages 50 and 70 and none had been treated with high blood pressure medication when the study began.

"One message of our finding may be that if you're noticing occasional memory lapses, high blood pressure may be a contributing factor," he says. Unfortunately, many people with high blood pressure are unaware they have it.

Jennings' finding may also add to the increasing body of evidence that suggests there is a strong link between stroke and heart disease, both of which can result from high blood pressure, and the severe memory loss seen in patients with Alzheimer's disease.

Two weeks ago, that relationship was detailed at the American Medical Association's annual conference for science reporters in Philadelphia by Vladimir Hachinski, MD, professor of neurology at the University of Western Ontario in Canada and editor-in-chief of the medical journal Stroke. He noted that within three months of having a stroke, about one in four patients develop significant memory impairment, and two in three eventually develop Alzheimer's disease. Likewise, those with Alzheimer's appear to be more prone to stroke.

"The key is prevention, and the time to do it is middle age," he tells WebMD. "By taking measures to reduce your risk of stroke and heart disease, you can also reduce the risk of Alzheimer's."

Show Sources

SOURCES: Jennings, J. Abstract presented at the American Heart Association's 57th annual High Blood Pressure Research conference, Washington, D.C., Sept. 23, 2003. Hajjar, I. The Journal of the American Medical Association, July 9, 2003; vol 290: pp 199-206. J. Richard Jennings, PhD, professor, psychiatry and psychology, University of Pittsburgh. Vladimir Hachinski, MD, professor, neurology, University of Western Ontario, Canada; editor-in-chief, Stroke.
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