Is There a Dose-Response Relationship Between Exercise and Cognitive Function in Older Adults?

Frost et al. conducted a modest-sized randomized controlled trial (n = 99) examining the effects of 6-months of high-intensity versus moderate-intensity aerobic exercise (AE) training versus an inactive control condition on several subdomains of executive function (EF; set-shifting, working memory, inhibition, verbal generativity, and visual reasoning) in cognitively unimpaired older adults. The study also examined the long-term effects of AE training on EF 12-months after completion of the intervention. The intervention had high adherence rates in both AE groups (mean >85%) and both AE groups showed greater improvement in cardiorespiratory fitness over 6-months relative to the inactive control condition. The primary study analyses revealed null results, such that no differences were observed between the high-intensity AE, moderate-intensity AE, and inactive control group for change in EF measures over the course of the 6-month intervention or the 12-month follow-up period. As such, the study results did not support the hypothesis that higher intensity of AE training would result in greater EF benefits. However, it is likely the study was underpowered to detect these effects given the 3-group intervention design in a modest-sized sample.