Heart failure (HF) is currently considered a common pathology, with 15 million adults in Europe and 26 million worldwide. The American Heart Association (AHA) estimates that their number will increase by 25% by 2030. In France, HF affects more than one million people. Because of the repeated hospitalizations of this disease, it is considered a costly pathology and with a high mortality rate (23.000 deaths per year in France). Moreover, HF is a severe pathology that affects the quality of life of patients and their families. Treatment and medical follow-up are required. A cardiac rehabilitation program is also a primary indication according to the latest recommendations and repositories in Cardiology. Various studies show that Interval Training exercise program improves VO2 peak compared to a continuous program, which constitutes a major prognostic factor in the population of heart failure. However, it is sometimes a difficult program to offer to more deconditioned patients as it requires reaching powers around 80% - 95% of its maximum exertion capacity. So, a variant of the interval training is offered, called Progressive Interval Training (PIT), based on the same model as the conventional interval training (CIT), but with an increasing power and breathing threshold, so that the patient can adapt gradually. The hypothesis is that PIT could improve VO2 peak better than CIT in cardiac rehabilitation program. Therefore, study the benefits of PIT training to improve the conditioning and quality of life of patients with chronic heart failure will be studied.