What Is Copd: Respiratory Health

Content provided by the Faculty of the Harvard Medical School

What is COPD?

Doctors group chronic bronchitis and emphysema together under the label of chronic obstructive pulmonary disease (COPD) because both cause respiratory symptoms and share a common cause — smoking. Many people with one disease also have the other. Symptoms of both these conditions vary from one person to the next and usually grow worse as the condition advances.

Most often, the disease begins when people are in their 40s or 50s, when they are active and at the peak of their careers. Patients live with the condition for decades as their progressive respiratory symptoms slowly impair their ability to do the activities they once enjoyed, things their peers can still do. One of the many tragic effects of this lung disease is that patients become old before their time.

A survey of patients by the American Lung Association reveals the scope of the disabilities this illness causes. Half of the people surveyed said they had to cut back on work. The same proportion said they had to scale back on social activities. Almost as many said they could not participate in family activities to the extent that they once did.

Chronic obstructive pulmonary disease is unique among the most disabling diseases in that it is almost completely preventable. The American Lung Association estimates that 80%–90% of cases are caused by smoking. If no one smoked, COPD would be a rare illness. Quitting smoking lowers your risk of developing this disease. If you have it already, quitting prevents further damage to your lungs and airways, even though it doesn't undo the damage that has already been done. Some people continue to smoke once they have been diagnosed because they think they have nothing more to lose. But quitting can make the difference between living for many years with a mild or moderate degree of impairment and living with symptoms that steadily become more severe, disabling, and ultimately deadly. (For a diagram of healthy lungs, see Figure 1.)

Figure 1: How you breathe When you take a breath, air travels through a system of increasingly smaller airways from the trachea, to the bronchi and then to tiny sacs known as alveoli (see inset). A system of tiny capillaries absorbs the oxygen through the walls of the alveoli and delivers it to cells throughout the body.

Last updated:	May 23, 2007