Effects of acute exercise on functional connectivity in young and older adults

Abstract

AbstractBackgroundPhysical activity has protective effects on cognition and brain health. Regular exercise contributes to better cognition, promotes functional and structural brain changes, and may even reverse age‐related decline to some extent. However, the effects of a single session of acute exercise on functional connectivity are currently unclear.MethodThe study sample comprised 59 healthy participants, 31 young adults (mean age: 22.3; 8 females) and 28 older adults (mean age: 55.8; 9 females). During their first visit, participants performed a submaximal exercise on a bicycle ergometer to measure their fitness level. During the second and third visits, participants took part in two counterbalanced MRI sessions: an Exercise session and a Relax session. In the Exercise session, participants received a 10‐minute resting‐state scan, followed by a 15‐minute period of aerobic exercise. After the exercise, participants received the second resting‐state scan. For the Relax session, the exercise was replaced by a 15‐minute rest period. Data analysis was performed in SPM8. For the functional connectivity (FC) analysis, 30 seeds were selected from the brain’s major functional networks and relevant subcortical regions. Seed2voxel FC was computed as Pearson’s correlation and transformed to Fisher’s Z. A cluster‐level FEW correction p < 0.05 was applied. Effects of acute exercise on FC were tested across and between the two groups using within‐subject ANOVAs controlling for fitness level and scan order. In addition, correlations and interactions were calculated between fitness level and exercise effects on rsFC.ResultAcross groups, acute exercise was associated with decreased FC of the caudate and the amygdala to the pre and postcentral gyrus. Significant group differences were observed for the putamen and intraparietal sulcus, PreCG and superior frontal gyrus: exercise effects on FC between these regions were significantly larger in young compared to older adults. A significant interaction effect between fitness level and group was found for FC of NAcc‐PCC/Precuneus, with a positive association in young individuals and a negative association in older individuals.ConclusionEven a single session of acute exercise affects functional connectivity in neural networks involved in motor processing and motivation. This relationship is different for young compared to older individuals.