Exercise intolerance along with dyspnea fatigue are cardinal symptoms of heart failure which adversely impact quality of life of the patient. Exercise improves well being in heart failure. ESC 2016 and AHA ACC 2013 heart failure guidelines recommend exercise to improve functional capacity QOL and also to reduce the risk of hospitalization in stable HF patients Class IA . The 6 minute walk test assesses functional capacity or exercise tolerance in patients with heart failure and defines prognosis. A 6 minute walk distance less than 200 m indicates lower functional capacity and carries a poor prognosis. If the walk distance is more than 500 m the prognosis is good. If the 6 minute walk distance ranges between 200m and 500 m patient can continue to exercise with oxygen supplementation. Oxygen saturation during 6MWT also has prognostic significance. A fall in oxygen saturation SpO2 during 6MWT of more than 4 indicates significant desaturation and is a predictor of mortality. The aim should be to increase exercise tolerance even if with oxygen supplementation.