Abstract
Research on the impact of physical activity (PA) has shown that PA produces changes in the structure and function of a brain structure called the hippocampus. There are three main limitations in this research. First, the majority of the work has been carried out in elderly populations and as such, there is a paucity of research on the impact of PA on the brains of healthy young individuals. Second, whereas PA is typically assessed through controlled interventions, changes in the brain due to PA as performed during daily-life activities has not been explored. Finally, the hippocampus has a complex internal structure and the impact of PA on this internal structure is unclear. Here we examined how structural and functional aspects of the hip-pocampus are associated with habitual PA performed during work, leisure time and sports in the daily lives of young healthy adults. We found that PA performed during work time correlated with increased subicular volumes and with changed functional connectivity between a location in middle/posterior hippocampus and regions of the default mode network and between a location in anterior hippocampus and regions of the somatomotor network. No effects of PA performed during leisure time and sports were found. The results generalize the impact of PA to younger populations and show how PA performed in daily-life situations correlates with the precise internal structure of the hippocampus.