Cognition and Physical Activity in the Elderly
Does moderate physical activity improve cognitive function for older adults?
The LIFE (Lifestyle Interventions and Independence for Elders) study was a randomized clinical trial of community-dwelling adults ages 70-89 years enrolled from eight US centers between February 2010 and December 2011. Participants were sedentary at baseline, but could walk at least 400 m. Subjects were randomized to a 24-month program of walking, resistance training, and flexibility exercises or a health education program (which also included upper-extremity stretching). The outcomes of interest included cognitive function (measured by the Digit Symbol Coding task, a subtest of the Wechler Adults Intelligence Scale) and the revised Hopkins Verbal Learning Test (a 12-item word list recall test). Additional outcomes included global and executive cognitive function, and incident mild cognitive impairment or dementia at 24 months.
A total of 1,635 participants were included in the study (818 in the physical activity arm and 817 in the health education arm). Cognitive function testing was completed in 1,476 participants, which has 90.3% of the cohort. Mean age of participants was 78.9 years, and 68% were women. A majority of participants had received a college education. At 24 months, the Digit Symbol Coding task and the Hopkins Verbal Learning Test were similar between the two groups, after adjustment for clinical site, sex, and baseline values. Mean Digit Symbol Coding task scores were 46.26 points for the physical activity group and 46.28 for the health education group (p = 0.97). Mean Hopkins Verbal Learning Test scores were 7.22 for the physical activity group and 7.25 for the health education group (p = 0.84). Incident mild cognitive impairment (measured by the modified mini mental exam) or dementia were not significantly different between the two groups (13.2% in the physical activity group and 12.1% in the health education group). Among participants who were 80 years or older (n = 307) and those with poorer baseline physical performance (n = 328), greater improvement in executive function was observed in the physical activity group compared to the health education group.
The investigators concluded that among sedentary older adults, moderate-intensity physical activity does not appear to improve global or domain-specific cognitive function.
These data suggest that moderate-intensity physical activity among older adults does not provide significant benefits in cognitive function, although some groups including those with poor baseline function may have received some benefit.
Keywords: Cognition, Dementia, Executive Function, Exercise, Geriatrics, Health Education, Life Style, Mild Cognitive Impairment, Primary Prevention, Resistance Training, Verbal Learning, Walking
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