The study used high-tech neuro-imaging to monitor the effect of exercise on the human brain to discover a positive link between physical activity and improvements in decision-making.

'Six months of brisk walking produced significant physical changes in the brains of the exercise subjects,' says psychologist Arthur Kramer. 'They had increased connections between neurons in parts of the brain that make a person better able to pay attention compared with people who were physically inactive.'

Molly Wagster, program director for neuro-psychology of ageing research for the National Institute on Ageing saw the findings of the study as very interesting and hopeful. 'Here's a demonstration where physical exercise in humans is something that produces not just a hedging against cognitive decline with age but actually shows that one can have improvement of cognitive function,' she said.

The findings may also be used to explain the common experience people report of being more alert and better able to think after exercise. Moreover, the report also supports a growing trend among therapists who are using exercise to help increase the attention span of children with attention deficit disorder, says Dr John Ratey, clinical associate professor of psychiatry at Harvard Medical School.

'It has come as a big surprise in neuroscience that physical activity is a big promoter for keeping our brains healthy and adaptive,' he says. 'This is the kind of data we need to reverse a growing practice of schools eliminating physical education as a cost-cutting measure,' he said.