Acute exercise induces cortical inhibition and reduces arousal in response to visual stimulation in young children

• Cortical oscillations are changed following acute physical exercise in young children.
• Global alpha-1 power is higher and frontal beta power is lower 20 min after exercise.
• This indicates a reduction of arousal and cortical inhibition following exercise.
• However, these effects have no influence on children's cognitive performance.

Physical exercise is known to induce a range of transient or sustained psychophysiological effects including stress reduction and improvements in cognitive performance. Previous studies in the area have focused on adults and there has been little research on the relationship between physical exercise and brain function in young children. This study examined the relationship between cortical oscillations, arousal and cognitive performance following physical exercise in 5/6-year preschoolers. Participants completed two counterbalanced sessions of 45 min exercise or a control condition. Electroencephalography (EEG) was measured at rest with the eyes closed and the eyes open, as well as during cognitive performance in a task requiring attention and reaction speed. This was done before (PRE) and after (POST) each session once the participants’ heart rate returned to within 10% of pre-exercise values. The percentage change in spectral power from PRE to POST (Δ) differed significantly between conditions. Specifically, Δ alpha-1 power differed significantly between exercise (+5%) and the control condition (−5.9%) with the eyes-open, but not with the eyes-closed. This effect did not significantly differ between cortical regions (i.e., it was global). Further, Δ beta-1 and Δ beta-2 power differed significantly between exercise (beta-1: −10.8%, beta-2: −23.8%) and the control condition (beta-1: −4.3%, beta-2: −5.3%) at frontal sites independent of visual input. Despite significant changes in resting state EEG, cognitive performance and task-related EEG remained unaffected by exercise. The results were interpreted to indicate cortical inhibition and attenuation of arousal in response to visual stimulation following exercise in young children.