- Cardiopulmonary Exercise Testing (CPT): Incremental symptom-limited exercise testing was performed on a cycle-ergometer(Ergo FIT®, model Ergo 167 Cycle, Pirmasens, Germany) using a computer-based ventilatory expired gas analysis system (VO2000, Medgraphics Corp., St. Paul, MN). All subjects underwent a CPT to determine the peak work rate and the peak oxygen uptake (peak VO2). The subjects' electrocardiographic recordings were monitored using a cardiac monitor, SpO2, BP and sensation of dyspnea and fatigue using the BE-CR-10. A gas analyzer (VO2000 Medgraphics®, St Paul MN, USA) was used to obtain the participants' VO2 at each stage of the test. The ergospirometric values were recorded by the mean value measured every three breaths using the Aerograph® program. The VO2 was determined choosing the higher and more coherent value in the final 30 seconds of each stage.