.jpg)
Keeping your heart fit and strong can slow down the ageing of your brain, US researchers say.
A Boston University team found healthy people with sluggish hearts that pumped out less blood had "older" brains on scans than others.
Out of the 1,500 people studied, the team observed that the brain shrinks as it ages.
A poor cardiac output aged the brain by nearly two years on average, Circulation journal says.
The link was seen in younger people in their 30s who did not have heart disease, as well as elderly people who did.
Lead researcher Dr Angela Jefferson said: "These participants are not sick people. A very small number have heart disease. The observation that nearly a third of the entire sample has low cardiac index and that lower cardiac index is related to smaller brain volume is concerning and requires further study."
The participants with smaller brain volumes on magnetic resonance imaging did not show obvious clinical signs of reduced brain function.
But the researchers say the shrinkage may be an early sign that something is wrong.
More severe shrinkage or atrophy occurs with dementia.
Click here to view article