The Effect and Cerebral Blood Flow Mechanism of Exercise on Executive Function among Young Adults: A Double-blinded Randomised Controlled Trial Study

Objective: Studies have demonstrated that exercise benefits executive function. However, it is still unclear which exercise mode is optimal for protecting executive function among young adults and the evidence of the cerebral blood flow (CBF) mechanism of exercise on cognition. Thus, this study aimed to compare the intervention effect and the CBF mechanism of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on executive function. Study design : This was a double-blinded randomised controlled trial study conducted from October 2020 to January 2021 (ClinicalTrials.gov identifier: NCT04830059). Ninety-three healthy young adults were randomized into the HIIT (N=33), MICT (N=32), and control groups (N=28). Participants in exercise groups were guided to perform 40 minutes of HIIT and MICT three times a week for 12 weeks, and the control group received health education for the same period. Executive function was measured by trail-making test (TMT), and CBF was measured by transcranial Doppler flow analyzer (EMS-9WA) before and after interventions. Results: The time of the TMT task among the MICT group improved significantly compared with the control group (β = -10.175, 95% CI = -20.320, -0.031). The PI (β = 0.120, 95% CI = 0.018, 0.222), RI (β = 0.043, 95% CI = 0.005, 0.082), and S/D (β = 0.277, 95% CI = 0.048, 0.507) of the CBF among MICT group improved significantly compared with the control group. The time of TMT was associated with the Vs (F = 5.414, P = 0.022), PI (F = 4.973, P = 0.012), and RI (F = 5.845, P = 0.006). Moreover, the accuracy of TMT was associated with PI (F = 4.797, P = 0.036), RI (F = 5.394, P = 0.024), and S/D (F = 4.312, P = 0.05). Conclusion: A 12-week MICT intervention improved CBF and executive function better than HIIT among young adults. Furthermore, CBF was one of the potential mechanisms that exercise improved the cognitive function of young people, which provided practical evidence for encouraging people to exercise regularly to maintain executive function and enhance brain health.