(HealthDay News) -- If you want your mind to stay sharp when you're 90, here's what you'll need to do.
Exercise moderately or vigorously at least once a week, live with someone, avoid smoking and continue to volunteer or work into your 70s or 80s.
A new study shows that seniors with at least a high school education and a ninth-grade literacy level who followed such a lifestyle were more likely to stay mentally fit than those who didn't.
"The take-home message from the study is, you can maintain your cognitive function in late life," said study author Alexandra Fiocco, a postdoctoral fellow at the University of California, San Francisco. "People are afraid they will experience cognitive decline as they age. But not everyone declines."
The study appears in the June 9 issue of Neurology.
Researchers examined about 2,500 men and women aged 70 to 79 living in Memphis, Tenn. or Pittsburgh, Pa. All were taking part in the Health, Aging and Body Composition study.
Cognitive skills were tested four times over the eight-year study: at the outset and at years 3, 5 and 8.
As time passed, many of the participants showed decline in cognitive function -- about 53 percent experienced minor cognitive decline and 16 percent showed major cognitive decline.
But about 30 percent of the participants showed no cognitive decline -- and a few even improved their scores on cognitive tests.
So, what separated those who experienced mental decline from those who stayed sharp?
Seniors who exercised moderately to vigorously at least once a week were 30 percent more likely to maintain their cognitive function than those who didn't exercise that often, according to the study.
Those who had at least a high school education were nearly three times as likely to stay sharp as those who had less education, while older adults with a ninth-grade literacy level or higher were nearly five times as likely to avoid mental decline as those with lower literacy levels.
Nonsmokers were nearly twice as likely to stay sharp as those who smoke.
And seniors still working or volunteering were 24 percent more likely to maintain cognitive function, as were people who didn't live alone.
"To this day, the majority of past research has focused on factors that put people at greater risk to lose their cognitive skills over time, but much less is known about what factors help people maintain their skills," Fiocco said.
Hypertension and diabetes showed little impact on cognitive skills.
Dr. John Hart Jr., a professor of behavioral and brain sciences and neurology at the University of Texas at Dallas, said patients often come in wanting to know exactly what they need to do to avoid the problems associated with aging.
No one really knows precisely what that prescription is, Hart said. But studies such as this shed light on some of the lifestyle factors that separate those who are experiencing healthy aging and those who aren't.
"These are exciting studies that are getting us closer and closer to finding out what you need to do for a healthy old age," he said.
For people looking to improve their cognitive condition, Hart said there is no one product on the market or type of mental exercise that has been shown to be beneficial above the others.
Instead, take up a different activity, volunteer, try new things to challenge your brain, he suggested.
"It always comes back to eat healthy, exercise, take care of yourself," Hart said. "Stay physically and mentally active, and you will increase your chances of successful aging."
For more on healthy aging, visit the U.S. Centers for Disease Control and Prevention.
By Jennifer Thomas
SOURCES: Alexandra Fiocco, Ph.D., postdoctoral fellow, University of California, San Francisco; John Hart Jr., M.D., professor, behavioral and brain sciences and neurology, University of Texas at Dallas; June 9, 2009, Neurology
Last Updated: June 08, 2009
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