Effects Of Acute Aerobic Exercise On Behavioral Pattern Separation Performance In Older Adults

Abstract

PURPOSE: Ample evidence suggests moderate-intensity aerobic exercise is beneficial for hippocampal structure and function. Furthermore, recent studies in younger adults suggest a single session of aerobic exercise provides immediate benefits to behavioral pattern separation performance, a highly hippocampal-specific memory task. However, no work has explored how a single session of aerobic exercise might alter pattern separation performance in older adults, who generally exhibit deficits in pattern separation performance and hippocampal deterioration in relation to younger adults. METHODS: To address this question, we conducted a within-subject acute exercise study in 31 cognitively healthy and physically active older adults (70.1 (±6.1) years). Participants performed baseline testing and then completed two experimental day visits in counterbalanced order. On the experimental days, they performed different iterations of a behavioral pattern separation task on the computer before and after 30 minutes of moderate intensity aerobic exercise on a cycle ergometer or 30 minutes of quiet seated rest. Linear mixed-effects model analysis was employed in which condition order was controlled for, time (pre vs. post) and condition (exercise vs. rest) were modeled as fixed effects, and subject was modeled as a random effect. RESULTS: No significant time by condition interaction effect was found for general object recognition (F(1,31) = 1.25, p = .267, η2 = .01) and a positive, but non-significant interaction effect was found for pattern separation performance following the exercise condition (F(1,31) = 3.56, p = .062, η2 = .04). Furthermore, a post-intervention only analysis indicated that there was no significant difference between the exercise and rest condition for general object recognition (F(1,31) = 1.46, p = .236, η2 = .05), but that participants performed significantly better on the pattern separation task (F(1,31) = 8.86, p = .006, η2 = .22) following the exercise condition. CONCLUSIONS: Our results suggest a single session of moderate-intensity aerobic exercise may lead to reduced interference and better pattern separation performance in healthy older adults, suggesting immediate benefits for hippocampal-specific memory function.