Inclusion Criteria:  Male gender, CABG surgery performed in the last one month, Patients with negative exercise test (on the 30 days after discharge).  Exclusion Criteria:  Valve surgery, Perioperative myocardial infarction assessed by electrocardiographic (ECG) and creatine kinase isoenzyme changes, Postoperative angina, diabetes mellitus, chronic renal failure, unstable angina, intermittent claudication, heart valve dysfunction (moderate or severe), severe cardiac arrhythmias, -Presence of symptoms at rest or with minimal exertion, Chronic obstructive pulmonary disease (>70% FEV1/FVC), and Any disorder that might influence exercise performance physically (e.g. severe back pain, history stroke).