Resting-state brain activity and association with physical activity

Introduction Normal aging is associated with alterations of functional connectivity in brain neuronal networks. Altered network connectivity may be associated with accelerated cognitive decline. Physical activity is considered a beneficial lifestyle factor for maintaining cognitive health. Higher intensities of physical activity may induce structural and functional changes in the brain, particularly in regions involved in cognitive functions. However, the underlying neural mechanisms are not widely investigated. Our aim was to examine the association between resting-state functional connectivity of brain networks previously associated with cognitive and motor functions, physical activity and cognitive performance in healthy older adults. Methods We analyzed resting-state fMRI, physical activity and neuropsychological data of 149 healthy older adults (mean age: 68 years). Physical activity was measured by using actigraphs worn for 7 days and categorized into moderate-to-vigorous activity. Euclidean norm minus one values used to represent mean overall physical activity. We used a hypothesis driven seed-based approach and data-driven independent component analysis to examine brain network activity of a priori selected brain regions and networks. Results No significant associations were found in the seed-based analyses. The independent component analyses showed spatially restricted effects of moderate-to-vigorous physical activity in frontal regions of the default mode and salience networks, at p < 0.01 uncorrected. Conclusion Different physical activity intensities were not significantly associated with resting-state functional connectivity of various brain networks in a sample of healthy older adults. This finding contrasts with the results of previous cross-sectional studies.