Hi Mary,   Thanks for your question. According to our "Check a Symptom," page the shortness of breath you describe can be a symptom of a number of things. To start the conversation with your doctor, you may want to look over some of these additional symptoms:   Do you have any of the following symptoms? shortness of breath or a cough that is worse when lying down need to prop yourself up with pillows to fall asleep swollen legs history of heart disease. If not, another cause of shortness of breath that gets worse with exertion is anemia, a low red blood cell count most often caused by iron deficiency. Clues that anemia is the reason include pale skin, heavy menstrual periods or rectal bleeding.   Shortness of breath could also be a sign that you might just be a little out of shape. Again, please consult with your doctor to go over this condition. Please let us know how you're doing in the future!