A Randomized Controlled Trial of High Intensity Exercise and Executive Functioning in Cognitively Normal Older Adults

Abstract Background There is a paucity of interventional research that systematically assesses the role of exercise intensity and cardiorespiratory fitness, and their relationship with executive function in older adults. To address this limitation, we have examined the effect of a systematically manipulated exercise intervention on executive function. Methods Ninety-nine cognitively normal participants (age=69.10 ± 5.2 years; n=54 female) were randomized into either a high-intensity cycle-based exercise, moderate-intensity cycle-based exercise, or no-intervention control group. All participants underwent neuropsychological testing and fitness assessment at baseline (pre-intervention), 6-month follow-up (post-intervention), and 12-months post-intervention. Executive function was measured comprehensively, including measures of each subdomain: Shifting, Updating/ Working Memory, Inhibition, Verbal Generativity, and Non-verbal Reasoning. Cardiorespiratory fitness was measured by analysis of peak aerobic capacity; VO2peak. Results First, the exercise intervention was found to increase cardiorespiratory fitness (VO2peak) in the intervention groups, in comparison to the control group (F =10.40, p =  Conclusions At the aggregate level, we failed to find evidence that six months of high-intensity aerobic exercise improves EF in older adults. However, it remains possible that individual differences in experimentally induced changes in cardiorespiratory fitness may be associated with changes in Updating/ Working Memory and Verbal Generativity.