High Blood Pressure and the Elderly Mind

Oct. 30, 2003 -- A new study shows that having mild hypertension may actually help older people think more clearly.

Israeli researchers say that among the 495 elderly patients they studied, those with slightly elevated blood pressure performed the best on tests gauging memory, concentration, verbal fluency, and visual retention. Those with normal blood pressure levels performed the worst on all tests except for verbal fluency. All the patients were between ages 70 and 85.

But this study, published in the October issue of the American Journal of Hypertension, doesn't suggest that high blood pressure -- a key risk factor in heart disease and stroke -- is good. Rather, the real message is that doctors should consider a patient's age when deciding how aggressively to treat high blood pressure.

"We already know that good control of blood pressure is the best protection for elderly people against stroke and heart disease," says Michael A. Weber, MD, past president of the American Society of Hypertension. He was not involved in the study but serves as an editor of the journal in which it was published.

"The important lessons from Israel is that when clinicians treat blood pressure in older people, they should be sensitive to the possibility that there could be subtle but important changes in how people react to that treatment," he tells WebMD. "Doctors should be on the lookout and either ease back a little on the treatment or try different medications."

And what does it mean to patients?

"This report indicates that some elderly people who are being treated aggressively may discover that their ability to think clearly may be slightly impaired," he says. "It's possible that when blood pressure is reduced too quickly or using certain types of drugs may have an effect on our thinking process."

This likely occurs because of a process called "auto-regulation," which controls blood supply to the brain so it can function normally when blood pressure drops.

"In young people, auto-regulation is very strong, so their brains are able to adapt to lower levels of blood pressure when it may be deprived of blood," says Weber, associate dean and professor of medicine at the State University of New York Health Science Center at Brooklyn. "But as you age, this auto-regulation becomes less efficient, and the brains of elderly people may take longer to adjust, sometimes days or even weeks. So by all means, treatment should be individualized, and age should be considered."

The Israeli researchers, led by Ester Paran and her colleagues at Ben-Gurion University of the Negev, studied patients in four groups -- half of whom were actively receiving treatment for high blood pressure. The patients either had normal blood pressure, high blood pressure that was controlled with drugs, high blood pressure with no treatment, or had high blood pressure that wasn't controlled with medication.

They found those who scored highest on the mental tests had a high blood pressure that was treated but not controlled with medication. High blood pressure is defined as anything above 140/90 and affects some 50 million Americans.

"After adjusting for confounding variables, treated but uncontrolled hypertensives performed significantly better" while those with normal blood pressure performed the worst, they write.