Regular physical activity is associated with greater cortical inhibition in middle‐aged adults: Findings from Barcelona Brain Health Initiative

Background Aging has been associated with changes in the mechanisms of brain plasticity, specifically with the reduction of motor cortex excitability and decreased effectiveness of mechanisms of cortical inhibition (Pascual‐Leone et al., 2011; Lissemore et al., 2018). Emerging evidence suggests that regular practice of physical activity, which can increase cardiorespiratory fitness (Sobol et al., 2016), may prevent age‐related decline in the mechanisms of brain plasticity (Gomes‐Osman et al., 2017). We therefore hypothesized that those who engage in more physical activity would have greater corticospinal excitability and more efficient cortical inhibition. Methods Seventy‐eight healthy adults (39 women), between 41 and 65 years old were included in the study. The amount of physical activity was assessed using a self‐reported 5‐point Likert scale where 1 equalled sedentary and 5 equalled engagement in aerobic physical activity >3 hours/week. The peak respiratory oxygen uptake (VO2 peak), aerobic threshold (VT1) and anaerobic threshold (VT2) were measured by cardiopulmonary exercise test with ventilatory gas analyses. Transcranial magnetic stimulation was used to assess resting motor threshold, motor evoked potential (MEP) amplitude and long‐interval intracortical inhibition (LICI), a measure of cortical inhibition. Results Spearman’s rank correlation revealed that greater engagement in regular physical activity was associated with higher VO2 peak (ρ=.470, p = .001), VT1 (ρ=.371, p = .001) and VT2 (ρ=.414, p = .001), and higher amplitude of resting MEP (ρ=.287, p = .018). Mann‐Whitney U tests revealed higher MEP amplitude (p =.003) and more efficient LICI (p =.018) in the group who exercised >3 hours/week compared to the sedentary group. Conclusions Regular physical activity in middle‐aged adults is related with better cardiorespiratory fitness, greater corticospinal excitability and more efficient cortical inhibitory mechanisms.