Can Exercise Keep Our Minds Sharp? Seems That Way

Some initial studies find that getting moving can help fight dementia, but more research needed.


Published: Tuesday, June 1, 2010 at 12:01 a.m.
Last Modified: Friday, May 28, 2010 at 3:08 p.m.

I do some of my best writing on the run. I mean literally. When the words won't come, when the syntax doesn't feel right, when I just can't figure out what angle to take on a column, I'll often go for a good, hard run.

And usually it works. With the sweat pouring and lungs working overtime, the mental fog lifts. I make connections I hadn't seen earlier. How to be clear becomes, well, a little more clear.

If you work out routinely, I bet you've had the same experience. Three researchers I interviewed for this story say they have achieved it regularly, on a treadmill, on outdoor runs and on a bicycle, respectively. A couple of studies seem to confirm it.

Can exercise help keep our minds sharp? And if so, can it help delay or prevent the truly terrifying mental deterioration of dementia, most commonly seen as Alzheimer's disease?

Researchers studying both animals and humans increasingly say the answer is yes.

Because the science of this mind-body connection is only about 15 years old, there are many caveats and a wide range of opinion on how effective exercise is. At one end of the continuum are people such as John J. Ratey, a Harvard University psychiatrist who wrote the intriguing 2008 book "Spark: The Revolutionary New Science of Exercise and the Brain."

Ratey says flatly that there is overwhelming evidence that exercise produces large cognitive gains and helps fight dementia.

"Look, the studies are very clear," he said when I called him. "Even if you're in middle age, and you begin to exercise three to four times a week, at fairly moderate rates ... adding some weights in there ... you're going to push back cognitive decline by anywhere from 10 to 15 years."

In his book, Ratey notes research that MRI scans of the brains of sedentary people who suddenly improve their fitness show increased volume in the hippocampus and frontal and temporal lobes, regions of the brain associated with cognitive functioning.

A panel of experts convened by the National Institutes of Health for a "State of the Science" conference last month on preventing Alzheimer's disease and cognitive decline was much more cautious. Looking at reducing the risk of "cognitive decline in older adults," it wrote: "Preliminary evidence suggests a beneficial association of physical activity and a range of leisure activities (e.g., club membership, religious services, painting, gardening) with the preservation of cognitive function."

I asked Mark Mattson, chief of the Laboratory of Neurosciences at the National Institute on Aging, for help in making some overall sense of this. Mattson's best guess is that sedentary, out-of-shape people who take up exercise may indeed see a significant improvement in their cognitive abilities. People who already are fit probably won't see much gain, he said.

"If you're overeating (and) not getting enough exercise, getting enough exercise is going to be good for your brain, just like it's good for your heart," he said.

This story appeared in print on page B7

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