Relations Between Cardiorespiratory Fitness and Cognition in Older Adults With Amnestic Mild Cognitive Impairment From the Aerobic Exercise and Cognitive Training (ACT) Trial: Sex Differences

Objective: To examine the associations of cardiorespiratory fitness with executive function, episodic memory, and global cognition and sex differences in these associations in community-dwelling older adults with amnestic mild cognitive impairment. Design: A cross-sectional study using baseline data from the aerobic exercise and cognitive training (ACT) trial. Setting: The ACT trial conducted exercise testing in an exercise laboratory and data collections in a research facility. Participants: ACT trial participants were recruited through referrals, registries, exhibits, flyers, media, and advertisements and screened for eligibility. To be eligible for this study, ACT enrollees needed complete data on all study variables. Among 146 ACT enrollees, 142 met eligibility for this study (N=142). Interventions: None. Main Outcome Measures: Cardiorespiratory fitness was measured as peak oxygen consumption (VO_2peak) with a peak cycle-ergometer test, executive function with the EXAMINER, episodic memory with the Brief Visuospatial Memory Test-Revised, and global cognition with Montreal Cognitive Assessment. Results: The average age of the sample was 73.8±5.8 years with 16.9±2.9 years of education, with 87.3% White, 51.4% men, and 69.7% married. After controlling for covariates, VO_2peak was significantly related to executive function (b=.037, standard error [SE]=0.015, P=.0154, semipartial [sr] correlation coefficient=.239) and episodic memory (b=.590, SE=0.226, P=.0102, sr=.216), but not global cognition (b=.074, SE=0.055, P=.1837, sr=.125). For men, VO_2peak was significantly associated with executive function (b=.063, SE=0.024, P=.0099, r=.430) and episodic memory (b=1.088, SE=0.312, P=.0009, r=.382). Conclusions: Our findings show that VO_2peak was associated with executive function and episodic memory in the overall sample and in men. Future studies can examine the longitudinal relations between cardiorespiratory fitness and cognition.