Limitations
First, the relatively small sample size, the short duration of the exercise program, the small number of training sessions for patients in the TRAINING group (twice a week), and the low adherence of some patients to the program may have decreased the power of the study to demonstrate possible intergroup differences. Subjects were encouraged to attend the sessions, and those who attended less than one session per week, or stopped the sessions, were excluded. A sample size of 72 participants, as calculated, was not achieved, and this is also a limitation. In addition, besides exercise, no other health instructions, such as nutritional or psychological support were given, which could have affected the final result. No data concerning chronic coronary syndromes or peripheral artery disease were collected, which may have had an impact on exercise. Finally, not all data derived from the CPX, including data on the respiratory exchange ratio, were addressed in this study - these could have revealed some differences between groups.Another important point is the subjectivity of the echocardiogram which can lead to quantification bias. Small variations in the acquisition at LV apical level, which do not have an anatomical marker, can result in distorted values. Images were acquired from the apical short-axis view when the visibility of the myocardial segments was clear. Additionally, we created another criterion to ratify the correct acquisition, which was the visualization of at least a trend of a counterclockwise rotation of these segments, which would be physiologically expected. Finally, it is important to remind that the examiner was blinded to the patient’s group allocation.