Exercise practice associates with different brain rhythmic patterns during vigilance

Cardiovascular fitness has repeatedly been associated to enhanced cognitive and brain functioning, generally in the form of differences in reaction time and response accuracy, as well as in event-related potentials (ERPs) and blood-oxygen-level-dependent imaging while participants performed executive demanding tasks. However, the evidence regarding potential differences in oscillatory neural activity, an inherent characteristic of brain functioning, is scarce. To fill this gap, here, we extracted and analysed (using a data-driven exploratory approach) brain oscillatory activity, both tonic (overall electroencephalographic - EEG - oscillatory activity) and transient (event related spectral perturbation [ERSP] and inter-trial coherence [ITC]), from a previous published dataset (Luque-Casado et al. 2016), where we showed different behavioural and ERP patterns during a vigilance/sustained attention task as a function of cardiovascular fitness in young adults. The ERSP results of the current study revealed increased theta (4-8 Hz) and upper beta (20-40 Hz) power and reduced lower beta (14-20 Hz) suppression after the target stimulus presentation in the higher-fit group compared to their lower-fit peers, but these differences disappeared in the second part of the task. ITC results mimicked the ERSP pattern within theta (4-8 Hz), while no differences were observed for the remaining frequency bands. Interestingly, the overall time-dependent effect in transient oscillatory activity followed the reaction time pattern of results. The analysis of the overall EEG oscillatory (tonic) dynamics did not show significant differences between groups. In sum, cardiorespiratory fitness was related to a brain oscillatory differential response pattern over a wide range of the frequency spectrum and spatio-temporal distribution, which seems to underlie the positive relationship between aerobic fitness and behavioural performance in a sustained attention task. Future studies are warranted to study the causal nature (beyond mere association) of these findings.