Exercise Boosts Your Brainpower; Intensity May Matter

It bears repeating: Exercise may be the single best thing you can do to keep all your marbles.

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In an attempt to hang on to your cognitive function as you age, you may do crossword puzzles, join a book club, or keep up friendships to stay connected. But to do all you can to maintain your mental abilities, you really should be exercising.

That's the conclusion of a review published this week by the Association for Psychological Science. It's not a new idea; the paper surveys the available research on the topic and concludes that cognitive enrichment activities—puzzles, social interaction, and the like—may well help you preserve brain function as you age. But they were especially complimentary towards physical activity. "What is most impressive to us," the authors write, "is the evidence demonstrating benefits of aerobic physical exercise on cognitive functioning in older adults."

Studies in both animals and humans "overwhelmingly" indicate that exercise helps the brain, they write, both generally and also specifically in executive functioning (things like deciding to change behavior or planning ahead), short-term memory, and focusing and maintaining attention. Arthur Kramer, a neuroscientist at the University of Illinois at Urbana-Champaign and one of the report's authors, said at a news conference Wednesday that there's enough evidence to launch a public policy campaign that includes an endorsement of exercise to improve brain function.

[Read how exercise revs up your brain.]

It doesn't surprise John Ratey, a psychiatrist at Harvard Medical School and author of Spark: The Revolutionary New Science of Exercise and the Brain. Exercise, like mental stimulation, provides a "challenge" to the brain, he says. "The brain needs to get the message that we need it to keep functioning," says Ratey. A bunch of different mechanisms are thought to be responsible for the exercise-brain connection, including a growth factor called FGF-2 that is produced by exercise and is thought to be involved in the generation of new neurons.

The authors of the new report emphasized the benefits of moderate exercise, saying that while walking distance was related to cognitive ability (the more you walk, the better), walking speed was not. That's certainly healthful, but Ratey says there might be additional benefits gained by interval training—short bursts of intense activity followed by rest periods.

[Check out whether you can really get a great workout in 3 minutes.]

When you exercise more intensely, your brain produces human growth hormone that cuts belly fat, adds muscle, and "pump(s) up" brain volume, Ratey explains in Spark. It also produces more nitric oxide than steady training, he told me this week. "That's the cardiologist's best friend; it does so many good things for the vascular system," he says, including acting as a "Roto-Rooter" for your small blood vessels.

While you should certainly speak with a doctor before starting any intense exercise program, particularly if you're new to exercise or have health issues, don't dismiss the idea entirely because of your age or physical condition. A 2007 study in Circulation found that even elderly heart failure patients, under medical supervision, benefited from interval training.

[Learn more about intervals and other time-saving ways to make your workout quick and sweaty.]