Cardiorespiratory fitness is associated with neuroelectric activity complexity in children with overweight or obesity

Cardiorespiratory fitness is one of the most important markers of health. Several studies have demonstrated the relationship between cardiorespiratory fitness and brain functioning in healthy children. Some of these works suggested that cardiorespiratory fitness may have a protective role on the executive function, which represents a set of cognitive mechanisms used to control and coordinate other cognitive abilities. This is particularly relevant in children with overweight or obesity. In these studies, neuroelectric activity is recorded using medical imaging techniques or electroencephalography (EEG). Among the EEG studies, analyses based on the P3 event related potential stand out. However, complementary analyses are necessary to understand the neural mechanisms underlying the associations between cardiorespiratory fitness and brain functioning. EEG complexity, a useful feature that measures the regularity of neuroelectric activity, has been previously associated with cardiorespiratory fitness in adolescents. In this work, we evaluate this association in a group of 87 Caucasian children with overweight/obesity. Our results reveal that the children with higher cardiorespiratory fitness present less EEG complexity while performing a cognitive task that challenges the executive function. In addition, they suggest that the line length, the metric that we used to estimate EEG complexity, performs equally well as those metrics based on the P3 and better than other complexity metrics like sample entropy, as an indicator of cardiorespiratory fitness. Finally, the line length has advantages over the P3: more consistency across EEG regions and cognitive loads, lower experimental complexity, lower computational cost, and higher automatization capability.