CHICAGO—Routine moderate exercise during middle age may help prevent mild cognitive impairment (MCI), investigators reported at the 60th Annual Meeting of the American Academy of Neurology.
“The association of physical conditioning with faster reaction times in athletes was reported as early as the 1930s,” said Yonas Geda, MD, MSc, a consultant in both the Department of Psychiatry and Psychology and the Division of Epidemiology, Department of Health Sciences Research at the Mayo Clinic in Rochester, Minnesota. Since then, basic science and clinical research studies, including the Canadian Study of Health and Aging and epidemiologic studies in the United States, have reported that physical exercise may protect against incident cognitive decline. Likewise, meta-analyses of interventional studies involving elderly individuals have described favorable effects of exercise on cognition in both healthy adults and patients with early Alzheimer’s disease.
“I think we are all familiar with the clichés about moderation to prevent a range of diseases or conditions, whether it involves alcohol, diet, or exercise. It was nice to be able to show empirically that moderate physical exercise can be protective,” Dr. Geda commented.
Reducing Mild Cognitive Impairment
Dr. Geda and colleagues reviewed physical exercise data obtained from 128 individuals ages 70 to 89 who had MCI and 740 cognitively normal elderly persons. As part of the ongoing Mayo Clinic Study of Aging, participants routinely undergo neurologic, psychometric, and neuropsychiatric evaluations. A consensus panel of physicians, nurses, and psychologists determines the classification of normal cognitive aging, MCI, or dementia, based on published criteria.
For the present analysis, subjects completed a questionnaire assessing the frequency and intensity of their exercise regimen during the preceding year, as well as during ages 50 through 65. Specifically, participants were asked if they exercised once a month, two to three times a month, once or twice a week, three to four times a week, or five to six times per week throughout the two time periods. The intensity of their physical activity was categorized as light (eg, bowling, walking leisurely, stretching, golfing with a golf cart, or slow dancing), moderate (eg, brisk walking, hiking, aerobics, strength training, golfing without a golf cart, swimming, tennis doubles, moderate use of exercise machines, yoga, martial arts, or weight lifting), or vigorous (eg, jogging, backpacking, bicycling uphill, tennis singles, racquetball, intense/extended use of exercise machines, or skiing).
Results showed that moderate physical exercise two to five times per week during ages 50 to 65 was associated with a significantly decreased risk of MCI. This was true for all but one of the six categories of exercise frequency examined. The group that exercised daily did not have a significantly reduced risk of MCI, but this finding may be due to the group’s small size, Dr. Geda suggested. The findings were not affected by age, gender, education, apathy, or depression. In addition, exercise habits during the year prior to the survey were not associated with a reduced risk.
Dr. Geda noted that although interpretation of his group’s findings is uncertain, physical exercise may be a marker for a healthy lifestyle.
Prospective Studies Needed
The results of the research may be weakened by the potential for recall bias, Dr. Geda emphasized, because the exercise data were dependent on the recall of the participants’ exercise habits from ages 50 through 65. He added, however, that other studies analyzing exercise data using objective measures, such as treadmill duration test and peak oxygen consumption, have reported similar findings (ie, that physical exercise protects against incident cognitive decline). Prospective cohort studies that measure incident MCI as an outcome are needed to corroborate the findings, Dr. Geda concluded.
—Jill Stein