Geda, Y., Roberts, R., Knopman, D., Christianson, T., Pankratz, S., Ivniks, R., Boeve, B., Tangalos, E., Peterson, R. & Rocca, W. (2010). Physical exercise, aging, and mild cognitive impairment: A population-based study. Archives of Neurology, 67(1), 80-86.
PURPOSE: Individuals with mild cognitive impairment (MCI) develop dementia at a faster rate than non-impaired individuals - 10%-15% per year compared to 1%-2%. Physical exercise has been known to decrease the risk of heart disease, type 2 diabetes, and some cancers. This study examined whether physical activity can help decrease the risks of MCI.
PARTICIPANTS: Subjects were recruited using stratified random sampling from Olmsted County, Minnesota. The sample consisted of equal numbers of males and females, with two groups, ages 70-79 and 80-89. Upon the first follow-up, participants were asked to complete a self-reported Physical Exercise Questionnaire; a total of 1,324 individuals without dementia completed this survey. Each participant was evaluated at the Mayo Clinic using three assessments: 1) neurological exam, 2) risk factor assessment, and 3) neuropsychologic testing. Cognitive domain scores were also obtained for each individual. Subjects were identified as having MCI, if they met the following criteria: 1) cognitive concern expressed by physician, 2) cognitive impairment, 3) normal functional activities, and 4) no dementia.
METHOD: Physical activity levels were measured using a self-reported questionnaire. Information included physical exercise performed at two time points. The first was within the year prior to cognitive assessment and the second was between the ages of 50 and 65 years. The questionnaire asked about light activities (leisure walking, slow dancing, bowling, etc.), moderate activities (swimming, tennis, yoga, etc.), and vigorous activities (jogging, backpacking, bicycling uphill, etc.). Further questions included determining the frequency of each of these exercises. A separate analysis was performed for activities within the year and for those between the ages of 50 and 65.
RESULTS: Light exercise and vigorous exercise were not statistically significant in reducing the odds of having MCI. However, the odds ratio for moderate activity in midlife was .58 (P =.008) and .68 for later in life (P = .02).
DISCUSSION: Moderate physical activity may reduce the odds of having mild cognitive impairment. Even activity later in life can have a significant impact. While this study did not show vigorous activity to have a statistically significant impact, this may have been because most of these participants did not engage in vigorous exercise later in life. Furthermore, using a self-report questionnaire might have allowed the result to reflect participant biases.