Study suggests link between brain’s blood supply, memory
DEAR DOCTOR: I’ve read that memory is linked to the heart’s ability to pump blood, with a reduced ability leading to poorer memory. Is there anything I can do to keep the blood flowing to my brain? DEAR READER: Our brains, like the rest of our bodies, rely on optimal blood flow for optimal functioning. But in the case of the brain, that means a larger volume than you would expect. While the brain accounts for just 2 percent of a person’s total weight, a series of specialized anatomical processes ensure that it gets a whopping 12 percent of the blood that flows through the body. And according to the results of an intriguing study published last fall, there appears to be a link between the brain’s blood supply and cognitive function.
The study, published online in the journal Neurology, looked at a group of individuals with an average age of 73 who are taking part in the Memory and Aging Project at Vanderbilt University Medical Center in Nashville. This is an ongoing study that tracks the health and cognitive abilities of the participants and analyzes the resulting data.
Using imaging techniques, researchers calculated how much blood each person’s heart pumped in relation to his or her body size, a value known as “cardiac index.” They also measured the resulting volume of blood flow in the brain. They found that a lower cardiac index correlated to reduced blood flow to the left and right temporal lobes, the memory-processing areas of the brain.
Reaction to the study is that the findings bolster what previous research has long suggested — there is a strong connection between the health of the heart and the health of the brain.
But the solution may not be as simple as joining a gym or heading out for a brisk walk. That’s because of those physiological mechanisms that dole out a proportionally greater blood flow to the brain than to other parts of the body. Whether these mechanisms are directly affected by the health of the heart, or whether their decline is related to advancing age or the onset of cognitive decline is not yet known.
Eve Glazier, M.D., MBA, is an internist and assistant professor of medicine at UCLA Health.
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