Want to develop your brain power? Exercise -- bicycling, walking or aerobics -- will boost your cognitive functions, say a flurry of recent studies.

'The science behind exercise increasingly shows that it provides a short-term boost to the ability to process data... Acute bouts of exercise have also been found to reduce depression, anxiety and illness,' says a report in The Wall Street Journal.

Quoting a flurry of studies in this regard, the report also said that exercise had helped ward off the mental effects of ageing, perhaps even Alzheimer's.

A study conducted with 884,715 students this year by the Journal Of Exercise Physiology revealed that the 'fittest students' scored more marks than those who were not as fit, the paper said. 'Results indicate a consistent positive relationship between overall fitness and academic achievement.'

Arthur Kramer, who is the director of the Biomedical Imaging Centre, said aerobics yielded a 20 percent improvement in performance. 'There were substantial effects of exercise on cognition (the mental process of knowing, including aspects such as awareness, perception, reasoning and judgment),' he said in his study published in 2003.

The evidence, the report said quoting Journal Of American Medical Association, was even stronger for long term benefits of exercise.

Now researchers are trying to determine just how much and what type of exercise produces the greatest cognitive benefits.

"How long do you need to exercise? At what intensity? And how long-lasting are the effects?" asks Jennifer Etnier, a University of North Carolina professor who is researching these questions.