Cognitive gains and cortical thickness changes after 12 weeks of resistance training in older adults with low and high risk of mild cognitive impairment: Findings from a randomized controlled trial

Background: In this randomized controlled trial, we assessed the neuroprotective effect of a 12-week resistance training (RT) program on executive control and cortical thickness of the prefrontal, temporal, parietal, and central cortex, regions prone to structural decline in individuals with mild cognitive impairment (MCI). Methods: Seventy older adults (aged 60-85 y old, 38 females and 32 males) were randomly allocated to a 12-week lower limb RT program or a waiting list control group. The Montreal Cognitive Assessment (MoCA) was used to stratify participants screened for high (< 26) or low (>= 26) MCI risk. Cognitive measurements consisted of the two-choice reaction time, Go/No-go, mathematical processing, and memory search tests. Cortical thickness was estimated from 3D T1-weighted MR images. Results: Complete randomized controlled trial data was obtained from 50 individuals (24 with high MCI risk). Significant Group x Time interactions were found for response on the Go/No-go task and cortical thickness of the right parahippocampal gyrus [F >= 5.3, p <= 0.03; eta(2)(p) >= 0.12]. An inspection of these observations revealed an increase in cortical thickness (+1.18 %) and a decrease in response time (-4.35 %) in individuals with high MCI risk allocated to the exercise group (both uncorrected p = 0.08). Decreased response time on the Go/No-go task was associated with increased cortical thickness in the right entorhinal gyrus (uncorrected p = 0.01). Conclusions: Our study demonstrated that 12 weeks of RT intervention may effectively improve cognitive performance and slow neuronal loss in the hippocampal complex of older adults at high MCI risk. Findings support evidence for the neuroprotective effects of resistance training and its potential role in cognitive health.