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Fit teens perform better on cognitive tests than their less fit peers, according to a new study.
By MSNBC contributor
updated 1/6/2010 8:21:31 AM ET 2010-01-06T13:21:31

If you’re trying to motivate yourself to get moving in the new year, here’s some added inspiration: Mounting research shows that exercise isn’t just good for the body, it’s also good for the brain — and not just the brains of older folks.

While much of the research on the effects of exercise on the mind has focused on countering dementia in seniors, recent studies show that kids and young to middle-aged adults can get a brain boost as well.

One large new study, for instance, found that teenage males in the best cardiovascular shape performed better on various cognitive tests at age 18 than their less fit counterparts. And those who improved their fitness levels between the ages of 15 and 18 achieved higher test scores than those who decreased their fitness during that time.

What’s more, the fittest 18-year-olds were more likely to achieve both higher educational and socioeconomic status later in life, according to results published in December in the Proceedings of the National Academy of Sciences.

“We cannot determine from this study alone that physical fitness causes better cognitive functioning,” says study author Georg Kuhn, a professor at the Center for Brain Repair and Rehabilitation at the University of Gothenburg in Sweden. “But taken together with other studies, we can assume that better cardiovascular fitness may optimize cognitive performance and academic achievements.”

Kuhn and colleagues based their conclusions on a study that followed more than 1.2 million Swedish men who were born between 1950 and 1976 and enlisted for mandatory military service at age 18. The group had more than 260,000 sibling pairs, including more than 3,000 twins, almost half of whom were identical twin pairs.

The identical twin data are particularly telling, allowing the researchers to more clearly show the effects of environmental influences such as exercise over genetic factors. “On an average, the fitter twin was also the twin that scored higher in the IQ tests,” Kuhn says.

Dr. John Ratey, an associate professor of psychiatry at Harvard Medical School in Boston and author of “Spark: The Revolutionary New Science of Exercise and the Brain,” calls the new paper a “huge and important study” that, while not proving a causal association, is powerful enough to get “close to fact.”

The Swedish researchers found that muscle strength did not correlate to cognitive function, supporting the notion that aerobic exercise that promotes healthy blood flow throughout the body also helps to nourish the brain, particularly young brains in development. Scientists believe this may boost cognition in various possible ways, such as by delivering growth factors or other helpful substances to the brain, promoting the growth of brain cells and healthy nerve connections, and reducing inflammation.

The new study expands on other research in recent years showing that physical fitness appears to help young school children do better academically. 10 ways to boost your brainpower

But the brains of young to middle-aged adults can benefit, too. There’s plenty of evidence that regular aerobic exercise can help the adult brain by reducing stress and anxiety, easing depression and fighting problems such as cardiovascular ills and diabetes that can promote strokes and cognitive decline, Ratey notes.

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There’s also other research showing that exercise may boost brain power in adults. One pivotal study published in 2007 showed that a 12-week aerobic exercise program increased blood flow to the brains of adults ages 21 to 45, and likely — based on similar studies in mice — promoted the growth of new nerve cells in the hippocampus, a region of the brain that’s important for memory and cognitive aging.

Better productivity
For people hoping to get a leg up at the office, Ratey says there’s every reason to think that regular aerobic exercise can only help. “At minimum, it will increase cognitive ability by 10 percent,” maybe as much as 20 percent, he says. And that’s enough to notice a difference in concentration, focus, stress management and mood.

Kevin Kent, 28, who works in finance in Chicago, is a firm believer that his lunchtime workouts in the gym of his office building help him to focus and concentrate at work.

“After a good 45- to 60-minute workout, I always return to the office awake and energized,” he says. “I have noticed this positive impact on numerous occasions and even go as far as prioritizing my day around this, saving more difficult tasks for right after lunch.”

Even though he’s away from his desk for about an hour, Kent feels he’s a better worker for it. “I am convinced that time is made up for with the increased productivity in the afternoon.”

The head of a consulting company that helps nonprofits raise funds, Kristy Hall, 35, of Charlottesville, Va., says she gets many of her ideas while running, sweating away on the elliptical machine or doing other forms of cardio.

“Exercise is like my muse,” she says. “It not only helps me focus or concentrate, it also is my path to innovation and inspiration.”

If she’s not sure what to do next with a particular project, for example, she’ll go exercise “and during that time a person’s name or idea will come to me, the next action becomes clear.”

Every reason to start now
While it’s never too late to begin reaping benefits from exercise, there’s every reason to start now to keep the brain healthy into old age.

“The brain just doesn’t start aging at 60,” says Dr. Gary Small, a professor of psychiatry and director of the UCLA Center on Aging. “We start seeing decline in the 40s.”

And bad health habits that lead to heart disease, diabetes and other problems that contribute to cognitive impairment over time can start in very young children, notes Small, who is also the author of books including “The Memory Prescription” and “iBrain.”

So how much exercise does the brain need, ideally? No one knows for sure.

Research has shown that as little as 90 minutes a week can lower the risk of developing Alzheimer’s disease, Small notes.

The Alzheimer’s Association recommends aiming for about half an hour a day of physical activity, such as walking, bicycling and yoga. Ratey suggests at least three to four times a week of activity that gets the heart rate up.

Thankfully you don’t have to train for an Ironman triathlon for your brain to benefit.

© 2013 msnbc.com

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