A study by Australian researchers has found that regular, moderate exercise may help improve memory in older people and delay the onset of dementia.
The study by researchers at the University of Melbourne has found that walking for the equivalent of two and a half hours a week can significantly improve memory problems in the over-50s.
The study, Fitness for the Ageing Brain, was led by Professor Nicola T. Lautenschlager, the Chair of Old Age Psychiatry at the university and involved 170 participants aged 50 and over, who had some memory problems but did not have dementia.
The study was carried out over an 18 month period at the University of Western Australia and is the first to show that moderate exercise can positively affect cognitive function.
The 170 participants were divided into two groups - one group continued their usual activities - the other took part in an 24-week home-based physical activity program of walking for three 50 minute sessions or doing other moderate exercise each week.
The participants in the exercise group did an average of 142 more minutes in a week, or 20 minutes in a day, than those in the control group.
Professor Lautenschlager says by the end of the study, participants in the exercise group performed better on cognitive tests and had better delayed recall and also had lower clinical dementia rating scores.
Professor Lautenschlager says the trial is the first to demonstrate that exercise improves cognitive function in older adults with subjective and objective mild cognitive impairment and the benefits of physical activity were apparent after 6 months and persisted for at least another 12 months after the intervention had been discontinued.
According to the World Health Organization an estimated 37 million people worldwide now live with dementia, with Alzheimer's disease making up the majority of cases and that figure is expected to increase rapidly over the next 20 years.
This means researchers are under pressure to find ways of delaying the onset of dementia and helping older people stay active and independent.
Professor Lautenschlager says the results were very promising because unlike medication, which has no significant effect on mild cognitive impairment, physical activity has the advantage of other health benefits such as preventing depression, improving quality of life, preventing falls, improving cardiovascular function and reducing disability.
Professor Lautenschlager says if the onset of dementia could be delayed by 12 months, there would be 9.2 million fewer cases worldwide.
The study is published in the Journal of the American Medical Association.