What is cause of shortness of breath?

Many causes: Shortness of breath has many potential causes, many benign but some serious. If associated with other symptoms or progressive, professional medical assessment is prudent. Blood tests (looking for anemia, etc.), cardiac and pulmonary abnormalities can be sorted out fairly easily. Then the underlying causes for those abnormalities can be sought. Psychological causes can be responsible as well.

Multiple: Too many to list...Talk to your physician for further evaluation.

Big list: Shortness of breath is due to a demand for oxygen by your body in excess of your capacity to deliver it. This can be due to anemia, heart dysfunction, lung disease or airway problems. These will all be aggravated by exercise and if severe can cause a problem going up stairs or even walking. This needs evaluation by your doctor as soon as possible.

Many things: There are many causes of shortness of breath. The easiest way is to compartmentalize into three categories. 1. Any problems with the heart – heart failure, enlargement of the heart, or valve disease of the heart. 2. Any problem with the lungs – asthma, COPD, fluid around the lungs, fluid in the lungs, or lung scarring to name a few. 3. Everything else – deconditioning or knee/hip pain for example.