The group that ate well and exercised regularly had an overall 30 percent improvement in mental function by the end of the four-month period, the researchers noted.
Physical activity does seem to have a direct effect on brain cells, Smith said. "There are neurochemical changes that happen with exercise, he said. There is increased production of brain-derived neurotrophic factor, which stimulates connection with other brain cells, he said, but also there is some evidence that it helps grow new brain cells."
And the combination of good eating and exercise also produced the expected physical advances. Diet-and-exercise participants lost an average of 19 pounds and lowered systolic blood pressure (the higher of the 120/80 reading) by 16 points and diastolic pressure by 10 points by the end of the four-month program.
Some experts believe the study has shortcomings, however. It's a well-done study, but one that has flaws, said Dr. Donald LaVan, a clinical associate professor of medicine at the University of Pennsylvania and a spokesman for the American Heart Association.
"Its entirely too small," LaVan said. "I would call it a keyhole study, suggestive but nothing definitive. Also, it did not have a control group to look at the effect of exercise alone. We need a bigger study with a longer duration and a control group for exercise alone."
Nothing in the study should deter anyone from exercising for the sake of the mind as well as the body, LaVan said.
"Exercise is great," he said. "But how much exercise itself contributes to mental function is not clear."
Advice on physical activity is given by the American Heart A
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