In an indication that the brain like the body needs exercise in old age, researchers reported that older people given training in mental functions stayed sharper for years afterward.

The training involved formal sessions using such things as mnemonics that teach people to remember by using acronyms and rhymes. But it is reasonable to infer that games like Sudoko that emphasize reasoning skills could have some of the same benefits, said Michael Mariske of the University of Florida, one of the authors of the study.

He said one of the study's surprises was that the impact of formal training in memory, reasoning and speed of thinking could still be traced five years later in a group of people who's average age was 73 when the research began.

And since the training lasted only 10 to 18 hours in all, "imagine if you could do something like Sudoko where people practice these skills every day," he said in an interview.

Sherry Willis of Pennsylvania State University, lead author of the study, said "Older adults really can continue to exercise mentally and to improve their cognitive abilities ... It's just like physical exercise ... Always challenge oneself. Don't do the same activity over and over in a routinized manner."

This and other research shows "the promise of non-drug treatments" to combat mental decline in aging, added Sally Shumaker of Wake Forest University School of Medicine.

"The medications available today produce only low to moderate improvements in mental function. And they can have adverse side effects," she said. "Showing that cognitive training can protect mental function means that individuals who cannot tolerate existing drugs would have additional treatment options."

INDEPENDENT LIVING

"It's possible to envision a future treatment approach that combines lifestyle and drug treatments to meet the specific needs of each individual," Shumaker added.

The study, published in this week's Journal of the American Medical Association, involved more than 2,800 people with an average age of 73 who were living independently in several U.S. cities. It ran from 1998 through 2004.

Some of those in the study were given the formal training in memory, reasoning and speed of processing plus booster sessions in ensuing years and others got no training.

"Immediately after training, individuals who were trained on memory or individuals who were trained on reasoning or speed showed significantly higher performance than those who received no training," Willis said.

After five years all trained participants reported less difficulty compared with the untrained group in performing important activities of daily living, the study said.

The research provides "limited evidence that cognitive interventions can reduce age-related decline in self-reported instrumental activities of daily living that are the precursors of dependence ... associated with increased use of hospital, outpatient, home health, nursing home services, and health care expenditures," the report concluded.

It cautioned, however, that more study is needed since it would probably take more than five years to find the full extent of the training, given that those studied were living independently when the research began.