Heart Failure with Reduced Ejection Fraction: Exercise Study

Participants needed to fulfil the following inclusion criteria to be eligible: (a) male or female aged between 50 and 70 years old; (b) diagnosed with HFrEF (left ventricular ejection fraction < 50%); (c) stable phase of the disease with no recent hospitalisation or visit to the emergency department due to heart failure (within the last six months before the beginning of the study); (d) New York Heart Association (NYHA) functional class I, II, or III; (e) under treatment with B-blockers; and (f) sedentary (i.e., not involved in exercise training for six months). The exclusion criteria were: (a) use of intravenous diuretics in the last six months; (b) unstable angina or evidence of severe ventricular arrhythmia; (c) atrial fibrillation; (d) supraventricular arrhythmias; (e) chronic obstructive pulmonary disease; (f) recent of haemoglobin concentrations outside optimal parameters (13–16.5 g·dL⁻¹); (g) physical limitations that impeded the completion of the ergometry; and (h) the presence of ischaemia, arrhythmias, or high frequency of ectopic heartbeats. All patients were fully informed and signed the informed consent before any procedure related to the study was performed. The protocol of this study was approved by the competent ethics committee of the host institution (PI2021-177).