Exercise has been shown to be good for the heart and also the brain. Now researchers may have come up with a possible explanation. They measured something called cardiac index, which is a marker for how much blood the heart pumps relative to body size. People with a lower cardiac index score also had demonstrable brain shrinkage. Roughly 1500 people were studied. The relationship was seen even for people in their thirties with no obvious heart disease. The investigators were quick to point out that smaller brain volume was not necessarily linked to cognitive decline, but it is associated with aging. They hypothesize that the pumping power of the heart could influence the amount of blood, oxygen and nutrients that get to brain cells.
[Circulation, online, August 2, 2010]
The People's Perspective on Medicine