Physical fitness and shapes of subcortical brain structures in children

Abstract

A few studies have recently reported that higher cardiorespiratory fitness is associated with higher volumes of subcortical brain structures in children. It is however unknown how different fitness measures relate to shape of subcortical brain nuclei. We aimed to examine the association of the main health-related physical fitness components with shape of subcortical brain structures in a sample of 44 Spanish children aged 9.7±0.2 years from the NUHEAL project. Cardiorespiratory fitness, muscular strength and speed-agility were assessed using valid and reliable tests (ALPHA-fitness test battery). Shape of the subcortical brain structures was assessed by magnetic resonance imaging, and its relationship with fitness was examined after controlling for a set of potential confounders using a partial correlation permutation approach. Our results showed that all physical fitness components studied were significantly related to shape of subcortical brain nuclei. These associations were both positive and negative, indicating that a higher level of fitness in childhood is related to both expansions and contractions in certain regions of Accumbens, Amygdala, Caudate, Hippocampus, Pallidum, Putamen and Thalamus. Cardiorespiratory fitness was mainly associated with expansions, whereas handgrip was mostly associated with contractions in the structures studied. Future randomized controlled trials will confirm or contrast our findings, demonstrating whether changes in fitness modify the shape of brain structures and the extent to which those changes influence cognitive function.