Effect of acute concurrent exercise training and the mediating role of lactate on executive function: An ERP study

Both acute aerobic (AE) and resistance exercise (RE) have been acknowledged to be effective methods in enhancing executive function and brain-related P3 amplitudes. Nevertheless, the effect of acute concurrent exercise training (CET), combining both AE and RE, on executive function remains subject to speculation. Moreover, investigation of the mechanisms that underlie improvements in executive function would facilitate scientific understanding. Notably, lactate has emerged as a candidate among several potential mechanisms. Therefore, the main aim of the present study was to investigate the effect of acute CET on the cognitive flexibility dimension of executive function using behavioural and neuro-electric measures. A secondary aim was to determine the mediating effect of blood lactate in the acute exercise-executive function relationship. Seventyeight young adults (38 women, 40 men; 22.8 +/- 1.8 years) were randomly assigned to one of the following groups: CET, AE, or reading control (RC). Cognitive flexibility was evaluated using the Task-Switching Test and its derived electroencephalography (EEG) was assessed immediately prior to and following each treatment. Fingertip lactate assays were taken prior to, at the midpoint, and after each treatment. Both acute CET and AE shortened response time regardless of test conditions when compared to the RC group. Greater P3 amplitude was observed following CET in the heterogeneous condition and under AE in the switch condition. A significant mediation of blood lactate for response time emerged in both the CET and AE groups for the heterogeneous and switch conditions. The blood lactate mediation was not reflected in P3 amplitude. The present findings suggest that acute CET leads to positive behavioural and neuro-electric alterations of cognitive flexibility, and its effect is similar to AE. Additionally, blood lactate serves as a mediator of the effects of acute exercise on executive function from a behavioural, but not neuro-electric standpoint.