High- and Moderate-Intensity Interval Training for Cardiac-Psychological Comorbidity: Results from a 4-Week Intervention

BACKGROUND: Anxiety and depressive symptoms are common in patients with cardiovascular disease (CVD) and are associated with poorer prognosis. Exercise-based rehabilitation may improve both psychological and cardiopulmonary outcomes in this population. OBJECTIVE: To evaluate and compare the short-term effects of high-intensity interval training (HIIT) and moderate-intensity interval training (MIIT) in CVD patients with comorbid anxiety and/or depression. METHODS: This retrospective real-world study screened 1,020 cardiac rehabilitation patients, of whom 112 were included in the final analysis. All participants completed a 4-week supervised outpatient HIIT or MIIT. Anxiety and depressive symptoms were assessed using the GAD-7 and PHQ-9, and cardiopulmonary fitness was evaluated by standardized cardiopulmonary exercise testing. RESULTS: After 4 weeks, in the HIIT group, GAD-7 and PHQ-9 scores decreased by 4.4 ± 4.3 and 3.7 ± 4.3 points (Cohen's d = -1.023 and -0.860; p < 0.001); in the MIIT group, the corresponding reductions were 4.8 ± 4.9 and 3.5 ± 4.0 points (Cohen's d = -0.980 and -0.875; p < 0.001). Both groups also demonstrated significant improvements in multiple cardiopulmonary parameters (all p < 0.05). Nominal between-group differences were observed for AT VO₂ and PETCO₂ before multiplicity correction, but neither difference remained statistically significant after FDR correction. CONCLUSIONS: In clinical practice, short-term HIIT and MIIT may both be feasible strategies to alleviate psychological symptoms and improve cardiopulmonary fitness in CVD patients with comorbid anxiety or depression.