Heart failure affects not only the cardiovascular system with structural abnormalities of the heart, but also the musculoskeletal system, leading to exercise intolerance. Objective: To evaluate the effects of a short-term exercise protocol and phototherapy, on the functional capacity and inflammatory markers in patients with heart failure. In addition, the investigators will investigate pulmonary function, peripheral and respiratory muscle strength and quality of life. Methods: Heart failure patients (left ventricular ejection fraction < 40%) will be selected from the outpatient clinic of the myocardium of the Department of Cardiology of Unifesp and randomized among two groups: patients who will be submitted to placebo phototherapy and cycle ergometer exercise; and patients who will be submitted to active phototherapy and cycle ergometer exercise. All groups will receive treatment twice a week for four weeks. Patients will be instructed to conduct home-based walking program at least twice a week. Patients will be evaluated before and after protocols regarding the pulmonary function, peripheral and respiratory muscle strength, functionality, quality of life and evaluation of systemic inflammatory mediators.