Introduction: HIIT has been proposed as an effective strategy in cardiac rehabilitation; however, the lack of clarity regarding optimal dosage may be limiting factor in its clinical application. Objectives: The objective of this systematic review is to determine the optimal dosage of HIIT and its impact on Vo2max in patients with heart failure. Methods: A search was carried out in 5 databases (PubMed, Scopus, Web Science, Cochrane Library and Medline). Studies that used the HIIT protocol and measured Vo2max were included. And they compared HIIT with MICT, SID or some strength program in patients with HF. Results: The results of an analysis that included 6 studies with a total of 505 participants with left ventricular ejection fraction (LVEF) between 35% and 50% compared high-intensity interval training (HIIT) with other exercise methods. The studies showed that the Frequency of Sessions: Varied between 3 and times per week. Session Duration: Between 28 and 47 minutes. Total Duration of Programs: Between 12 and 54 weeks. The effectiveness of the training was measured with parameters such as Vo2max, resting heart rate, power in watts, maximum force in one repetition (1RM), and peak oxygen consumption. The results suggest that HIIT is more effective in improving Vo2max than other methods, and this effectiveness is maintained regardless of the type of heart failure: reduced, moderately reduced or preserved. Conclusion: The findings of the systematic review support the effectiveness HIIT as an exercise training option for patients with HF.