Shortness of breath, or dyspnea, is an uncomfortable condition that makes it difficult to fully get air into your lungs. Problems with your heart and lungs can harm your breathing. Some people may experience shortness of breath suddenly for short periods of time. the most common causes of dyspnea are asthma, heart failure, chronic obstructive pulmonary disease (COPD), interstitial lung disease, pneumonia, and psychogenic problems that are usually linked to anxiety. If shortness of breath starts suddenly, it is called an acute case of dyspnea. Heat and moisture from steam may also break down mucus in the lungs, which might also reduce breathlessness. To try steam inhalation at home, a person should: fill a bowl with very hot water. add a few drops of peppermint or eucalyptus essential oil.