CPET: Following baseline measures, each patient will undergo CPET using cycle ergometer (Cosmed, Rome, Italy). Silicone face masks will be harnessed over the subject's nose and mouth to monitor the resting and exercise gas exchange measurements. Subjects are connected to electrocardiogram (ECG), saturation and blood pressure monitors. Exercise time is 8-12 minutes and total test duration is 45-60 minutes. The test is non-invasive and within the limits of the test, it is safe. The test begins with a no resistance warm up lasting 1 to 3 minutes and followed with a gradual increment in resistance adapted to the patient's functional capacities according to the examiner's free judgment and ranging 5 to 25 Watts/minute. Pulmonary function tests rest will be recorded prior to CPET and 10 minutes post exercise. The cardio-respiratory parameters measured include respiration rate (RR), heart rate by 12-lead ECG (HR), oxygen saturation (SpO2), blood pressure (BP), tidal volume (TV), minute ventilation (VE), breathing reserve (BR), oxygen consumption (VO2), VCO2 (carbon dioxide flow rejected by the ventilation system), respiratory equivalents (VE/VO2, VE/VCO2), end tidal carbon dioxide (ETCO2), anaerobic threshold (AT), oxygen pulse (O2 pulse), respiratory exchange ratio (RER) at rest, during exercise and recovery . The combination of data collected allows analysis of the subject's ability during exercise.