We report secondary findings from a randomized controlled trial on the effects of exercise on memory in older adults with probable MCI. We randomized 86 women aged 70–80 years with subjective memory complaints into one of three groups: resistance training, aerobic training, or balance and tone (control). All participants exercised twice per week for six months. We measured verbal memory and learning using the Rey Auditory Verbal Learning Test (RAVLT) and spatial memory using a computerized test, before and after trial completion. We found that the aerobic training group remembered significantly more items in the loss after interference condition of the RAVLT compared with the control group after six months of training. In addition, both experimental groups showed improved spatial memory performance in the most difficult condition where they were required to memorize the spatial location of three items, compared with the control group. Lastly, we found a significant correlation between spatial memory performance and overall physical capacity after intervention in the aerobic training group. Taken together, our results provide support for the prevailing notion that exercise can positively impact cognitive functioning and may represent an effective strategy to improve memory in those who have begun to experience cognitive decline. 1. Introduction Cognitive decline is one of the most pressing health care issues of the 21st century. Currently worldwide, one new case of dementia is detected every seven seconds [1] and the number of people affected is projected to be over 80 million by 2040 [1]. Thus, the societal value of developing effective intervention strategies cannot be overstated [2]. To date, pharmacological interventions for dementia have remained medically challenging at best. As a result, there has been growing interest in exercise training as an alternative intervention strategy. The primary aim of our current study was to investigate the efficacy of exercise as an intervention strategy to improve memory performance in older adults who have already begun to experience cognitive decline—namely, those with mild cognitive impairment (MCI). MCI is characterized by cognitive decline that is greater than expected for an individual’s age and education level, but does not significantly interfere with everyday function (i.e., instrumental activities of daily living) [3]. Importantly, MCI is a well-recognized risk factor for dementia; longitudinal studies report that seniors with MCI develop Alzheimer’s disease at a rate of 10–30% annually [4, 5], compared
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