A recent study offers a hint that the best way to keep your mind sharp is to take care of your body, particularly your heart.
Study subjects whose hearts pumped the most blood had the largest brains. As the brain ages, it tends to shrink, and a decrease in brain size is considered a sign of brain aging. But there were no obvious signs of diminished brain function seen in study subjects who had the lowest brain volume. So while the study does not link blood flow to mental capacity, it does suggest that the relationship between the two bears further investigation.
Both the group with lowest cardiac index (those whose hearts pumped the least effectively) and the group with middle cardiac index had brains that appeared, on average, two years older than the group with highest cardiac index index (as judged by brain volume).
It's been known for some time that poor heart health increases the likelihood of developing certain cognitive impairments, such as dementia. But little is known about the relation between circulation and brain health in people with average heart function.
The researchers measured cardiac index, the amount of blood the heart pumps relative to a person's body size, and brain size, both by MRI scan. When the subjects were grouped into thirds, based on their cardiac index, the researchers found some surprising results. Both the group with lowest cardiac index (those whose hearts pumped the least effectively) and the group with middle cardiac index had brains that appeared, on average, two years older than the group with highest cardiac index (as judged by brain volume).
Most of the study subjects were in good health. Only 7% had heart disease, and the relationship between blood flow and brain size held even for people who did not have heart disease.
Since the decrease in brain volume was seen even in study members with average blood flow, one possible interpretation of the results is that maintaining the best possible blood flow may delay the inevitable decrease in brain size that accompanies aging.
There are certainly reasons why lower blood flow could lead to worsened brain health. Less blood flowing to the brain means less oxygen and nutrients for brain cells to utilize. But as the researchers emphasize, it's way too early to dole out health advice based on such a preliminary study. But like many others, the study does suggest that heart and brain health go hand in hand.