Most cases of shortness of breath are due to heart or lung conditions. Your heart and lungs are involved in transporting oxygen to your tissues and removing carbon dioxide, and problems with either of these processes affect your breathing. If shortness of breath happens when you're clearly not exerting yourself, when you're doing something you normally could do without feeling winded, or comes on suddenly, those are warning signs that a heart issue could potentially be to blame. First Aid For Difficulty Breathing - Loosen any tight clothing. Help the person use any prescribed medicine (such as an asthma inhaler or home oxygen). Continue to monitor the person's breathing and pulse until medical help arrives. DO NOT assume that the person's condition is improving if you can no longer hear abnormal breath sounds, such as wheezing. Heart and blood conditions Anemia. Heart failure. Conditions that affect your heart muscle (cardiomyopathy). Abnormal heart rhythm (arrhythmia).