There is no cure for emphysema. Treatment includes stopping smoking and taking medicines ('broncho-dilators' and sometimes corticosteroids). Supplemental oxygen is recommended in those with low oxygen levels at rest. It decreases the risk of heart failure and death if used 15 hours per day, and may improve people's ability to exercise. In those with normal or mildly low oxygen levels, oxygen supplementation may improve shortness of breath. There is a risk of fires and little benefit when those on oxygen continue to smoke.