Exercise training in patients with chronic stable heart failure (HF) is a recommended and broadly accepted treatment strategy that is an integral part of an evidence-based management involving pharmacological and non-pharmacological therapies. There is ample scientific evidence that exercise training in HF with reduced (HFrEF) and with preserved ejection fraction (HFpEF) improves exercise capacity, HF symptoms and quality of life. This is due to an improvement of central hemodynamics, endothelial function, neurohumoral activation, skeletal muscle structure and function as well as a decrease in inflammatory markers. The largest randomized, controlled HF-ACTION study (Heart Failure-A Controlled Trial Investigating Outcomes of exercise TraiNing) demonstrated that exercise training results in a modest improvement of all-cause mortality and hospitalizations in HFrEF, depending on adequate compliance. Outcome data in HFpEF are lacking. Besides compliance, efficacy of exercise training is dependent on the intensity and type of exercise. Resistance and high intensity endurance training in addition to a standard aerobic exercise seem to be superior in improving the clinical status of HF patients. In the future, individualized exercise programs will help to improve long-term adherence to exercise training.