Author(s): ZHANG, B., SUN, F., Institution: THE EDUCATION UNIVERSITY OF HONG KONG, Country: HONG KONG, Abstract-ID: 2078

INTRODUCTION:
Recent evidence suggests that engaging more physical activity could benefit executive function (EF). Additionally, high-intensity interval training (HIIT) has gained attention as a time-efficient training protocol with positive impacts on various health outcomes including EF. However, the effects of different HIIT protocols remain unknown. Therefore, the current study aimed to compare the effects of two different HIIT protocols, i.e., high-intensity circuit training (HICT) and traditional cycling-based HIIT (TC-HIIT), on EF of sedentary young females. The potential neurophysiological mechanisms were also explored.
METHODS:
Forty-five sedentary young females (age = 22.3 ± 2.2 years, BMI = 20.6 ± 2.0) were recruited and randomly assigned into three different groups: HICT group, TC-HIIT group and Control group. Prior to and following an eight-week intervention period, the participants EF was assessed by a battery of computer tests, including Stroop test, N-back test and Task switching test. Additionally, blood samples were collected to measure several neurophysiological biomarkers associated with EF, namely Brain-derived neurotrophic factor (BDNF), Insulin-like growth factor 1 (IGF-1), and Cathepsin B (CTSB).
RESULTS:
In Stroop test, both HICT and TC-HIIT group significantly improved the accuracy and reaction time (p < 0.05), whereas during the post-test, the HICT group exhibited significantly lower reaction times compared to the TC-HIIT group (p < 0.05). In N-back test, both intervention groups displayed a significant reduction in reaction time (p < 0.05). However, an improvement in accuracy was only observed in the TC-HIIT group (p < 0.05). In Task-switching test, significant improvements were only found in TC-HIIT group in both accuracy and reaction time (p < 0.05). No significant change was found in the Control group in any tests. Regarding the blood analysis, no significant changes were detected either within or between the groups in BDNF, IGF-1 and CTSB.
CONCLUSION:
The results of the current study provide evidence that HIIT can be an effective strategy for enhancing EF, regardless of the HIIT modalities. However, it seemed that the observed positive effects on EF were not directly associated with the neurophysiological biomarkers examined in the present study. Thus, future research should explore potential mechanisms underlying these effects, such as investigating brain hemodynamic responses and exploring alternative biomarkers.