Effects of variable-intensity interval training and moderate-intensity continuous aerobic exercise on executive function and underlying neural mechanisms in male college students

This study involved 51 male college students who were recruited and randomly assigned to one of three groups: a variable intensity interval training (VIIT) group, a moderate-intensity continuous training (MICT) group, and a control group (n = 17 each). Interventions are carried out for 6 weeks and three times a week, and the total duration of each test is about 53-61 min. Participants in the two intervention groups engaged in cycling exercises of different intensities, the entire experiment was conducted in a climate-controlled laboratory environment maintained at a constant temperature of 23 ± 1 °C. and the executive function and prefrontal hemodynamic responses of the participants were assessed before and after the intervention. Outcome measures included accuracy (ACC), reaction time (RT), and changes in oxyhemoglobin concentration (ΔHbO₂). Postintervention results indicated that both the VIIT and MICT groups had significantly greater ACC in inhibitory control tasks compared with preintervention values and that of the control group (P < 0.05). RTs were significantly reduced in both exercise groups compared with their baseline values and that of the posttest control group (P < 0.05), whereas no significant differences were observed in the control group (P > 0.05). Hemodynamic data revealed significantly increased ΔHbO₂ after VIIT in channels 41, 42, and 44 (dorsolateral prefrontal cortex), channels 26 and 27 (frontopolar area), and channel 4 (ventrolateral prefrontal cortex) (P < 0.05). In the MICT group, channels 42, 27, and 4 also presented significant increases in ΔHbO₂ (P < 0.05). With respect to updating functions, RT significantly decreased postintervention in both exercise groups (P < 0.05), with the VIIT group showing shorter RT than the control group (P < 0.05) and the MICT group displaying greater ACC than controls (P < 0.05). VIIT elicited significant increases in ΔHbO₂ in channels 40 and 43 (frontopolar area) and channel 41 (P < 0.05), whereas MICT resulted in significant activation only in channel 40 (P < 0.05). For the task-switching function, both the VIIT and MICT groups demonstrated significantly reduced RTs after training (P < 0.05), with no significant change in the control group. In the VIIT group, channels 42, 44, and 4 presented significant increases in ΔHbO₂ (P < 0.05). In conclusion, both VIIT and MICT effectively improved executive function performance in male college students, VIIT exhibited a more pronounced increase in prefrontal ΔHbO₂, with activation primarily localized to the frontopolar, dorsolateral, and ventrolateral regions, whereas MICT also demonstrated noticeable activation in several brain regions.