The low-level laser therapy (LLLT) has been used in many inflammatory disorders.

More recently the LLLT was associated with an improvement in the muscle strength, endurance and functional capacity.But, these effects were described only in health or athletic individuals. In this randomized and controlled clinical trails, the investigators will study the effects of LLLT on functional capacity of the patients with Coronary artery bypass surgery.

This study will be conducing in a large hospital that is reference in Coronary artery bypass surgery. 15 patients will be randomized for placebo or low-level laser therapy (LLLT). The functional capacity will be test by test six-minute walk test before and after de LLLT. Moreover the application of LBP or placebo will be followed by assessments of muscle damage and oxidative stress. One-week interval between the LLLT will gave to reduce the influence between the treatments.

Inclusion Criteria:

• Patients in the postoperative period of elective CABG referred for cardiac rehabilitation, which are the 15th and 30th days after surgery without ischemic changes and / or complex arrhythmias on the electrocardiogram, between 40 and 75 years of age who have performed the first surgery.

Exclusion Criteria:

• Patients with decompensated heart failure; presence of any comorbidity such as: unstable angina; associated neurological disease; moderate respiratory illness to severe pre-diagnosed by the attending physician; active infectious disease or fever; disabling peripheral vascular disease; unstable ventricular arrhythmias; diabetes mellitus; use of cardiac pacemaker, musculoskeletal disease that limits physical activity, patients with a BMI ≥30.