Staying mentally sharp as you age may have more to do with working out than working on crossword puzzles, new research suggests.

People who stayed physically active into old age tended to have larger brains than those who did not exercise in the study, published in the journal Neurology. The brain typically shrinks in late adulthood, and this shrinkage is believed to play a role in age-related memory decline.

The new research is the latest to suggest that exercise is good for the brain, as well as the body. "It is pretty clear that exercise is one of the most potent things we can do to protect our brain as we age," says University of Pittsburgh exercise and aging researcher Kirk Erickson, PhD, who was not involved with the study.

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