October 24, 2006
How mentally sharp you remain in old age is linked to your physical fitness, researchers report. A sharp memory is also linked to your IQ score as a child, though robust physical health was a stronger indicator of mental fitness. The findings appeared in Neurology, a medical journal from the American Academy of Neurology.
Doctors in Scotland examined 460 men and women who had been participants in the Scottish Mental Survey of 1932. The participants were given cognitive tests at age 11, and then tested again using the same tests nearly 70 years later, at age 79. As seniors, the study group was also tested for physical fitness, including how long it took them to walk six meters (about 18 feet), how strong their hand grip was, and how strong their lung function and breathing capacity were.
The researchers found that, as a group, the more physically robust an individual was in old age, the more likely he or she was to have an intact memory. Physical fitness appeared to account for more than three percent of the differences in cognitive ability in old age, after accounting for differences in the participants' test scores at age 11.
"The other remarkable result was that childhood IQ was significantly related to lung function at age 79," said study author Ian Deary, Ph.D., of the University of Edinburgh in Scotland. "Participants with a high IQ as a child were more likely to have better lung function at age 79. This could be because people with higher intelligence might respond more favorably to health messages about staying fit."
However, the study found physical fitness has a greater impact on cognitive ability in old age than childhood IQ. "The important result of the study is that fitness contributes to better cognitive ability in old age," says Deary. "Thus, two people starting out with the same IQ at age 11, the fitter person at age 79 will, on average, have better cognitive function."
The findings are consistent with numerous earlier studies showing that physical activity may be key to keeping the brain young. In addition to exercise, a heart-healthy diet, mental stimulation, and other lifestyle measures have all been linked to maintaining a sharp memory.
The study also found that the type of job one had during one's life and one's level of education were associated with fitness at age 79. People in professional occupations and with more education tended to be more fit and had higher scores on memory and thinking tests.
Wellness programs aimed at making older people fitter are good candidates to improve cognitive aging, the researchers say. Alzheimer's, however, is a complex disease with genetic and environmental factors all playing a role. No one measure can guarantee you'll stay sharp into old age, but at the least, a healthy lifestyle may help.
For more on the risk factors for Alzheimer's disease and ways you might help prevent it, visit www.ALZinfo.org.
I.J. Deary, L.J. Whalley, G.D. Batty, and J.M. Starr: "Physical Fitness and Lifetime Cognitive Change." Neurology, Volume 67, October 10, 2006: page 1195