Researchers at the University of Montreal and its affiliated Institut universitaire de geratrie de Montreal Research Centre studied 31 young people between the ages of 18 and 30 and 54 older participants aged between 55 and 75.

"Our body's arteries stiffen with age, and the vessel hardening is believed to begin in the aorta, the main vessel coming out of the heart, before reaching the brain," said Claudine Gauthier, first author of the study.

"Indeed, the hardening may contribute to cognitive changes that occur during a similar time frame.

"We found that older adults whose aortas were in a better condition and who had greater aerobic fitness performed better on a cognitive test.

"We therefore think that the preservation of vessel elasticity may be one of the mechanisms that enables exercise to slow cognitive ageing," Gauthier said.

The researchers compared the older participants within their peer group and against the younger group who obviously have not begun the ageing processes in question.

None of the participants had physical or mental health issues that might influence the study outcome.

Their fitness was tested by exhausting the participants on a workout machine and determining their maximum oxygen intake over a 30 second period. Their cognitive abilities were assessed with the Stroop task.

The Stroop task is a scientifically validated test that involves asking someone to identify the ink colour of a colour word that is printed in a different colour.

A person who is able to correctly name the colour of the word without being distracted by the reflex to read it has greater cognitive agility.

The participants undertook three MRI scans: one to evaluate the blood flow to the brain, one to measure their brain activity as they performed the Stroop task, and one to actually look at the physical state of their aorta.

The researchers were interested in the brain's blood flow, as poorer cardiovascular health is associated with a faster pulse wave, at each heartbeat which in turn could cause damage to the brain's smaller blood vessels.(KH)