Tonic and transient oscillatory brain activity during acute exercise
The physiological changes that occur in the main body systems and organs during physical exercise are well described in the literature. Despite the key role of brain in processing afferent and efferent information from organ systems to coordinate and optimize their functioning, little is known about how the brain works during exercise. The present study investigated tonic and transient oscillatory brain activity during a single bout of aerobic exercise. Twenty young males (19-32 years old) were recruited for two experimental sessions on separate days. Electroencephalographic (EEG) activity was recorded during a session of cycling at 80% (moderate-to-high intensity) of VO2max (maximum aerobic capacity) while performing an oddball task where participants had to detect infrequent targets presented among frequent non-targets. This was compared to a (baseline) light intensity session (30% VO2max). The light intensity session was included to control for any potential effect of dual-tasking (i.e., pedaling and performing the oddball task). A warm-up and cool down periods were completed before and after exercise, respectively. A cluster-based nonparametric permutations test showed an increase in power across the entire frequency spectrum during the moderate-to-high intensity exercise, with respect to light intensity. Further, we found that the more salient target lead to lower increase in (stimulus-evoked) theta power in the 80% VO2max with respect to the light intensity condition. On the contrary, higher decrease alpha and lower beta power was found for standard trials in the moderate-to-high exercise condition than in the light exercise condition. The present study unveils, for the first time, a complex brain activity pattern during acute exercise (at 80% of maximum aerobic capacity). These findings might help to elucidate the nature of changes that occur in the brain during physical exertion.