## 4 Discussion  
The results of our study demonstrated that CE significantly improved key biomechanical parameters, such as cadence, in HFpEF patients. These improvements in cadence were strongly associated with increases in walking distance, HRmax, and exercise intensity during the 6 MWT, suggesting that CE can effectively improve overall functional capacity in this patient population. In contrast, HIIT did not significantly change these parameters. These findings underscore the potential of CE as a superior intervention to address multifaceted impairments in HFpEF patients, particularly in improving gait efficiency and exercise tolerance, which are critical for maintaining functional independence in these patients. Subgroup analyses further confirmed that CE is more effective in older patients (\(\geq\)70 years), males, and participants with a lower basal cadence (\(<\)120 steps/min). These results are consistent with previous research highlighting the benefits of CE programs in patients with HF. Studies have shown that the integration of aerobic and strength training significantly improves functional capacity, exercise tolerance, and muscle strength in patients with HFpEF [11]. The lack of significant effects observed with HIIT in our study contrasts with some previous research that has suggested potential benefits  
Figure 3: Associations between changes in cadence and distance, HRmax and exercise intensity in the 6 MWT. CE: combined exercise; HIIT: high-intensity interval training; CG: control group; HRmax: maximum heart rate. [PERSON]’s correlation coefficients were used. (**A**) Cadence (steps/min) vs. Distance (m), (**B**) Cadence (steps/min) vs. HRmax (beats/min), (**C**) Cadence (steps/min) vs. Exercise intensity (%). of HIIT in other forms of HF [30]. However, the variability in results may be attributable to differences in patient populations, the severity of HF, or the specific design of the exercise protocols used [31]. Overall, our results align with the growing body of evidence supporting the efficacy of CE as a comprehensive approach to improve physical function in HFpEF patients, while highlighting the need for further exploration of the role of HIIT in this specific patient group. In our study, we observed that CE significantly improved cadence, HRmax, and exercise intensity during the 6 MWT in patients with HFpEF. These improvements suggest that CE improves gait efficiency and overall cardiovascular response during physical activity, contributing to improved performance on the 6 MWT. Previous studies have similarly reported that exercise interventions can improve these parameters, with increased cadence linked to improved gait economy and higher HRmax and exercise intensity, reflecting improved cardiovascular fitness [22]. The physiological basis for these improvements is likely due to improved peripheral muscle function and cardiovascular adaptations, such as increased stroke volume and improved autonomic regulation, which together reduce the effort required to walk and allow patients to maintain higher intensities during the test. These adaptations help patients with HFpEF overcome some of the exercise limitations imposed by their disease, thus improving their functional capacity [32]. The consistency of our results in the per-protocol and intention-to-treat analyses underscores the robustness and reliability of the CE intervention in improving key outcomes such as cadence, HRmax, and exercise intensity during the 6 MWT in patients with HFpEF. Clinically, this consistency is significant because it suggests that the benefits of the exercise program are evident not only in patients who strictly adhere to the protocol but also in the broader patient population, including those with different levels of adherence [33]. This finding increases the generalizability of the intervention, indicating that even with typical variations in patient engagement and adherence, CE remains an effective strategy for improving functional capacity in HFpEF patients.