In this study, the sample size was calculated using G*Power 3.1.9.7 software. Referring to the meta-analysis by Hu et al. (2021) on the effects of HIIE on executive function in adolescents, the effect size (ES) was extracted as 0.38. The significance level (α) was set at 0.05, and the power (1-β) was set at 0.8. The calculation indicated that a total of 49 participants were needed, meaning that 25 participants were required for each of the HIIE and control groups. Additionally, another 25 participants were recruited for the MICE group to compare the intervention effects of HIIE and MICE on executive function in adolescents. Therefore, a total of 75 participants were needed for this study. The participants in this study were low-SES obese adolescents. Firstly, communication was established with a junior high school in a rural area to screen for obese adolescents. Secondly, the SES of the screened obese adolescents was assessed to identify those with low SES. A total of 120 participants were ultimately recruited for the study. To ensure the accuracy of the study results, the following inclusion criteria for participants were established in this study:

(1) Adolescents aged between 12 and 15 years old. (2) Using the Children and Adolescents BMI Calculator¹, the BMI index of each adolescent is calculated based on their height, weight, age, and gender, and those identified as obese are included. This calculator is developed based on the BMI screening criteria for overweight and obesity among Chinese students (Ji, 2004) and shows no discrepancy from manual calculations. (3) The MacArthur Scale of Subjective Socioeconomic Status is used to evaluate the SES of adolescents (Galvan et al., 2023), and those with an SES score below 5 are included. (4) Adolescents with no history of major diseases, such as cardiovascular diseases, respiratory diseases, or neurological diseases, to ensure the safety of exercise interventions. (5) Adolescents who have no medical contraindications to exercise, such as unrecovered joint injuries or severe musculoskeletal disorders, and who are able to engage in regular physical activity without restrictions. (6) Adolescents with normal vision or corrected vision, and no color blindness or color weakness. (7) Adolescents with normal intelligence and mental status. (8) If a participant is absent from exercise sessions more than twice, they will be excluded from the data analysis.

After preliminary screening and assessment, 36 adolescents who did not meet the criteria were excluded, resulting in a total of 84 participants for the study. These participants were randomly assigned to three groups: the HIIE group, the MICE group, and the control group, with 28 participants in each group. Randomization was achieved using a computer-generated random number method to ensure the randomness and balance of group assignment, thereby minimizing the impact of intergroup differences on the study results. This study was approved by the Scientific Research Ethics Committee of Hainan Police College. All participants provided informed consent, and both the participants and their guardians were fully informed about the purpose, methods, procedures, and potential risks of the study, and they voluntarily agreed to participate in this research.

Two coaches are assigned to guide the HIIE group and the MICE group, respectively, during the exercise to ensure the accuracy of the intervention measures. The training programs of the HIIE group and the MICE group are significantly different. Having separate coaches for each group can ensure that the training of each group is carried out strictly in accordance with the established program, guarantee the accuracy of the intervention measures, and reduce the deviation in the implementation of the training program caused by human factors. In addition, it can also avoid cross-interference and eliminate the influence of the coaches’ personal preferences. If the same coach is in charge of guiding both groups, there may be an inadvertent infiltration of the training methods or concepts of the HIIE group into the MICE group, or vice versa, thus affecting the independence and purity of the training of the two groups. However, having two coaches guide the two groups, respectively, can effectively avoid such cross-interference, keep a clear boundary for the training interventions of the two groups, reduce the influence of confounding factors on the experimental results, and ensure that the experiment can accurately evaluate the respective effects of the two training methods, namely HIIE and MICE. The specific intervention plans for HIIE and MICE are detailed as follows:

In this study, the statistical analysis was conducted using the SPSS 26.0 software (IBM, New York, NY, United States). For continuous variables, descriptive statistics were carried out using the mean (M) and standard deviation (SD); for categorical variables, descriptive statistics were performed using frequencies and percentages. Firstly, the Shapiro–Wilk test was combined with the P–P plot and Q–Q plot to conduct the normality test of the data. It was found that the continuous variables approximately presented a normal distribution. Therefore, One-way ANOVA was used for the between-group comparative analysis of the pre-test data. Secondly, ANCOVA was employed to analyze and compare the impact of HIIE and MICT interventions on executive functions and BMI among obese adolescents with low SES. In all statistical analyses, a significance level of p < 0.05 was set as the criterion for statistical significance of the differences, and p < 0.01 was set as the criterion for highly statistical significance of the differences.

There were no significant differences in age, gender composition ratio, SES, and BMI among the HIIE group, MICE group, and the control group (p > 0.05). The basic information of the three groups is detailed in Table 1.

The results (Table 2) of the intergroup comparative analysis of executive function among the HIIE group, MICE group, and the control group before the intervention show that there were no significant differences in reaction time and accuracy among the three groups in the GO/NO, 2-back, and More odd-shifting tasks (p > 0.05). Therefore, the executive functions of the participants in each group were at a roughly similar level before the intervention, which ensures the accuracy of the research results.

During the intervention process, the average heart rate of the HIIE group was (170.88 ± 10.01) beats per minute, and the average heart rate of the MICE group was (130.56 ± 9.06) beats per minute. The difference between the two groups was statistically significant (t = 14.93, p < 0.001). In addition, a comparative analysis of the average weekly heart rates between the HIIE group and the MICE group is shown in Figure 1. The above results indicate that the intervention process strictly adhered to the heart rate monitoring protocol, which can ensure the accuracy of the research results.

For BMI, after controlling for relevant confounding factors, the between-subjects main effect of the intervention was significant (F = 12.447, p < 0.001, η² = 0.260). Further pairwise comparisons showed that BMI in the HIIE group (25.65 ± 0.96) was significantly lower than that in the MICE group (26.32 ± 1.03; p = 0.027) and the control group (26.83 ± 1.75; p < 0.001). BMI in the MICE group (26.32 ± 1.03) was significantly lower than that in the control group (26.83 ± 1.75; p = 0.008). The results of between-group comparisons between the HIIE group and MICE group after intervention are presented in Figure 5.

The results of this study show that HIIE can effectively promote the development of executive function in obese adolescents from low SES backgrounds, especially in terms of reaction time of inhibitory control, reaction time and accuracy of working memory, as well as reaction time and accuracy of cognitive flexibility. This finding further supports previous studies (Reyes-Amigo et al., 2022; Tottori et al., 2019), indicating that HIIE has a positive effect on the executive function of adolescents. The positive impact of HIIE on the executive function of obese adolescents from low SES backgrounds is attributed to multiple factors, including the improvement of cardiovascular function, the regulation of brain-derived neurotrophic factor (BDNF), and the enhancement of neural plasticity.

The results of this study show that the average heart rate of the HIIE group is relatively high, which means a stronger stimulation to the cardiovascular system, and thus can promote the development of the cardiopulmonary function of adolescents (Nagashima et al., 2010). Related studies (Birkett et al., 2019; Neuendorf et al., 2023) have found that after HIIE training, the individual’s maximal oxygen uptake (VO₂max) increases significantly, which means that the body can absorb and utilize more oxygen, providing a more sufficient energy supply for the brain. When the brain receives sufficient oxygen and nutrients, the metabolic activities of neurons become more active, and the synthesis and release of neurotransmitters are also more stable, thus helping to improve executive function (Ogoh, 2017; Poels et al., 2008). In addition, BDNF plays a crucial role in the intervention of HIIE on executive function. Relevant studies (Li et al., 2022; Rentería et al., 2020) have found that HIIE can significantly increase the expression and secretion of BDNF. After BDNF enters the brain through the bloodstream, it binds to the receptors on the surface of neurons, activates downstream signaling molecules, promotes the proliferation, survival, and differentiation of neurons, enhances synaptic plasticity, and thus promotes the development of executive function (Kowiański et al., 2018; Lu et al., 2023).

The intense exercise stimuli during HIIE can prompt the brain to undergo a series of adaptive changes. At the neuronal level, HIIE can increase the dendritic branches and spine density of neurons, thereby expanding the information transmission network among neurons (Dos Santos et al., 2020; Li et al., 2020). Some studies (Dos Santos et al., 2020; Li et al., 2020) have found that after a period of HIIE training, the dendrites of neurons in brain regions closely related to executive function, such as the hippocampus and prefrontal cortex of experimental animals, become more complex. This implies that more synaptic connections can be established among neurons, improving the efficiency and accuracy of information transmission. In addition, the realization of executive function depends on the coordinated work of multiple brain regions, such as the prefrontal cortex, parietal cortex, and hippocampus (Aron, 2008). And HIIE can enhance the neural connections among these brain regions, enabling them to conduct information exchange and collaboration more effectively when performing tasks (Calverley et al., 2020).

The results of this study found that MICE can effectively improve the executive function of obese adolescents with low SES, especially reflected in the response time and accuracy rate of inhibitory control and working memory, as well as the accuracy rate of cognitive flexibility. This result is consistent with the findings of previous studies (Liu et al., 2020). Regarding the explanation of its internal causes, it can be explained from the aspects of stable cardiopulmonary function stimulation and metabolic regulation.

MICE is carried out at a relatively stable moderate intensity, keeping the body in an aerobic metabolism state for a long time. During the exercise, the stroke volume of the heart gradually increases, which can more effectively deliver oxygen-rich blood to the brain (Lee et al., 2023). This, in turn, enhances the metabolic activities of neurons, thus providing a good physiological foundation for the development of executive functions (Ogoh, 2017; Poels et al., 2008). In addition, MICE can also promote vascular health, enhance vascular elasticity, reduce vascular resistance, and improve the blood circulation in the brain, ensuring that all areas of the brain can receive sufficient nutrients and oxygen, and thus having a positive impact on executive functions (Oliva et al., 2023; Ramos et al., 2015).

The MICE can regulate the energy metabolism and material metabolism of obese adolescents. In terms of energy metabolism, MICE can increase the body’s energy consumption, promote the oxidation and decomposition of fat, help obese adolescents lose weight, and reduce body fat content (Nassis et al., 2005; Rowlands et al., 1999). Relevant studies (Laurent et al., 2020; Mamrot and Hanć, 2019) shows that the improvement of body composition is conducive to the development of adolescents’ executive function. In terms of material metabolism, MICE can promote the synthesis and release of neurotransmitters such as dopamine and serotonin, thereby promoting the development of executive functions (Tsai et al., 2024).

Overall, both HIIE and MICE have positive effects on different dimensions of executive function, namely inhibitory control, working memory, and cognitive flexibility. However, there are differences in specific effects. Among them, MICE has a better intervention effect on the accuracy rate of inhibitory control, while HIIE has a better intervention effect on the reaction time of cognitive flexibility. This provides a basis for diverse choices for improving executive function through exercise intervention.

The results of this study are similar to previous research, all indicating that HIIE and MICE have a selective promoting effect on executive function. However, there are still inconsistencies when it comes to specific related indicators. For example, a systematic review and meta-analysis (Wu et al., 2023) comparing the effects of HIIE and MICE interventions on the inhibitory control of healthy populations found that there was no significant difference in the intervention effects between MICE and HIIE. Jia (2022) explored the effects of HIIE and MICE interventions on the executive function of obese adolescents and also found that both HIIE and MICE could improve the executive function of obese adolescents, but the effect of MICE intervention on working memory was better than that of HIIE. In addition, exercise adherence may be a potential factor contributing to the differences in the effects of the two exercise modes. Although in this study, the adolescents in both the HIIE group and the MICE group were able to complete the training tasks well, the high-intensity exercise phase of HIIE is somewhat challenging, and it also brings more a sense of accomplishment and freshness, which may increase their exercise motivation and adherence. In contrast, the exercise intensity of MICT is relatively low, and the exercise process is relatively monotonous, which may make some adolescents feel bored during the training process, thus affecting their exercise adherence. Higher exercise adherence means that adolescents can participate in the training more actively and better achieve the training goals. Therefore, they may obtain more positive exercise effects in the more complex executive control task of cognitive flexibility.

The results of this study showed that both HIIE and MICE exerted positive improving effects on participants’ BMI, with HIIE yielding superior intervention outcomes. This finding is consistent with the core consensus in the existing field of exercise intervention, confirming the effectiveness of physical exercise in improving weight-related indicators (Abdelbasset et al., 2020; Gremeaux et al., 2012). The more favorable intervention effect of HIIE may be attributed to its unique physiological mechanism. In contrast to the stable and continuous energy expenditure of MICE, HIIE generates higher instantaneous energy consumption during exercise and triggers a more significant excess post-exercise oxygen consumption effect, enabling the body to maintain a high metabolic level even after exercise and prolonging the duration of fat oxidation for energy supply (Panissa et al., 2021). Additionally, HIIE features shorter exercise duration and higher time efficiency, which is more conducive to enhancing participants’ long-term exercise adherence and lays a solid foundation for the sustained improvement of BMI (Tschakert and Hofmann, 2013). This is also consistent with the conclusions of previous studies that HIIE has greater advantages in weight management, further verifying its potential as a preferred exercise modality for BMI intervention (Wewege et al., 2017). Furthermore, these findings provide empirical support for the formulation of individualized exercise intervention programs in the future, namely that HIIE can be prioritized for populations requiring efficient BMI improvement.

The results of this study have important guiding roles in the formulation of exercise intervention programs for obese adolescents from low SES backgrounds, school physical education, and community health promotion.

In terms of formulating exercise intervention programs, the research findings provide a scientific basis for precisely formulating exercise intervention programs for obese adolescents from low SES backgrounds. The research results suggest that when formulating exercise intervention programs, the exercise methods can be selectively chosen in a targeted manner according to factors such as the physical conditions, hobbies, and exercise goals of adolescents. For adolescents with better physical fitness, a stronger sports foundation, and a desire to significantly improve their executive function in the short term, HIIE can be preferentially recommended; while for adolescents with relatively weaker physical fitness, those who are just starting to exercise, or those who prefer a steady improvement in their health level, MICE may be a more suitable choice.

In terms of school physical education, it provides a reference for the setting of school physical education curriculums and the improvement of teaching methods. When designing physical education curriculums, schools can add teaching contents of HIIE and MICE to enrich the diversity of physical education curriculums and meet the exercise needs of different students. In physical education teaching, a combination of HIIE and MICE can be adopted, enabling students to experience the exercise effects of different exercise intensities in a single physical education class. In addition, teachers can conduct stratified teaching for students according to the results of their executive function tests. For students with relatively weaker executive function, more attention and guidance can be given to help them improve their executive function through exercise.

In terms of community health promotion, it helps communities carry out more targeted adolescent health promotion activities. Communities can formulate health promotion plans suitable for obese adolescents from low SES backgrounds according to the research results, and organize regular HIIE or MICE exercise activities. Through the active participation and promotion of the community, a good exercise atmosphere can be created to promote the healthy growth of obese adolescents from low SES backgrounds.

Firstly, this study has certain limitations in terms of sample size. Although 120 obese adolescents from low SES backgrounds were selected as participants in the study, from a statistical perspective and considering practical promotion and application, the sample size is relatively limited. Among the group of obese adolescents from low SES backgrounds, there may be significant individual differences due to different regions, family backgrounds, and living environments. A relatively small sample size may not comprehensively cover these differences, resulting in insufficient representativeness of the research results and having a certain impact on the universality and reliability of the research conclusions. Future research can further expand the sample size to include obese adolescents from low SES backgrounds in different regions and living environments, so as to improve the representativeness and promotional value of the research results.

Secondly, in terms of the experimental period, the exercise intervention period of this study is 12 weeks, which is relatively short. Although significant improvements in the executive function of obese adolescents from low SES backgrounds were observed after 12 weeks of HIIE and MICE, the long-term effects of exercise on executive function remain unclear. The development and improvement of executive function is a long-term process. A short-term exercise intervention may only initiate the relevant physiological and psychological mechanisms. The continuous promoting effect of long-term persistent exercise on executive function, as well as the maintenance of executive function after the cessation of exercise, still requires further research. Subsequent research can extend the experimental period, set different time points for measurement, and observe the long-term dynamic changes in the impact of exercise on executive function.

Finally, the research design did not include a dietary intervention-related module, resulting in incomplete variable control. Focusing on comparing the intervention effects of the two exercise modes, this study did not systematically assess or control the participants’ dietary status, nor did it set up a combined diet + exercise intervention group. Consequently, it was unable to quantify the regulatory role of dietary factors in the effectiveness of exercise interventions. Therefore, this study suggests that subsequent research may incorporate dietary assessment and intervention components. On one hand, systematic collection of participants’ dietary data through dietary diaries, food frequency questionnaires, and other methods can be used to analyze the regulatory effect of dietary patterns on exercise intervention outcomes. On the other hand, separate exercise groups, dietary intervention groups, and combined diet + exercise intervention groups can be established to compare the improvement effects of different intervention modes on executive function, BMI, and related physiological indicators.