It is estimated the number of people with Alzheimer's Disease will jump from 26 million today to 106 million worldwide by the year 2050.  As researchers work to find a cure for the deadly brain disease, experts are looking for ways to delay the onset of dementia caused by Alzheimer's.  VOA's Jessica Berman reports.

Experts say the number of people afflicted with Alzheimer's will quadruple by the middle of the century because people around the globe are living longer and Alzheimer's tends to strike older individuals.

But a new study suggests that the dementia that is a hallmark of the disease could be delayed among patients who exercise moderately three times per week.

Researchers at the University of Western Australia conducted a study involving 138 adult men and women aged 50 and over that had memory problems, but not dementia.  

The participants were randomly assigned to a moderate intensity exercise program for six months.  Researchers had them exercise an average of 50 minutes three times per week.  Most of them walked.  The other group was educated about exercise, but was not encouraged to do so.  

At the end of the study, those in the regular exercise group did better on cognitive tests to assess their memory, according to Nicola Lautenschlager, a psychiatrist who specializes in the elderly.  

"What we do not know at this point of time is the mechanism underlying this effect," said Nicola Lautenschlager.

Researchers found the benefit was small, with a modest improvement on the cognition scale.  But Lautenschlager says the study showed that exercise is more effective than medication, which has little or no effect at improving mild memory loss.

Lautenschlager is sufficiently encouraged that she says doctors may change their advice to patients with Alzheimer's disease.

"We need to reconsider what we recommend to older people when they ask us what kind of healthy lifestyle do I need to do to protect my brain," she said.

The study on the benefits of exercise in delaying the dementia in Alzheimer's disease is published in the Journal of the American Medical Association.