It's the fourth leading cause of death in the United States, but many people have never even heard of it.
Chronic Obstructive Pulmonary Disease or COPD is a lung disease that combines emphysema and chronic bronchitis, making it difficult to breathe.
Shortness of breath is often accompanied by chronic coughing and increased mucus.
Doctors make a diagnosis by using spirometry. "It consists of blowing into a machine and if you can't give the air as quick as you should for your age you are likely a diagnosis of COPD," says Dr. Bartolome Celli from the American Lung Association.
The American Lung Association says the majority of cases are caused by smoking cigarettes, so quitting helps.
A patient's condition can also be improved through therapy for the lungs and regular exercise.