High-Intensity Interval Training (HIIT) and Moderate Continuous Training (MCT) are widely employed strategies in the rehabilitation of cardiovascular diseases, differing in their physiological mechanisms and potential benefits. Objectives: This study aimed to identify the most effective dose of HIIT and MCT to optimize training in patients with heart failure (HF) and evaluate the impact of HIIT on Vo2max. Materials and Methods: A systematic review of randomized controlled trials conducted between 2010 and 2024 was performed using databases such as PubMed, Scopus, Cochrane, and Web of Science. Sixteen studies comparing the effects of HIIT and MCT on Vo2max and other clinical outcomes were included. Results: Analyses were conducted using a random-effects model, yielding an average standardized mean difference of 0.41 (95% CI: 0.12 to 0.70), indicating a moderate positive effect in favor of HIIT (t(15) = 3.05, p = 0.008). However, significant heterogeneity among studies was observed (I = 69.5%; Q(15) = 45.10, p < 0.0001). These findings suggest that HIIT may be more effective than MCT in improving Vo2max in patients with heart failure. Conclusions: Although the results are promising, variability among studies highlights the need for an individualized approach to exercise prescription to optimize the benefits of cardiac rehabilitation programs. maximize each swimmer's potential, leading to more effective and efficient skill and capacity development.