Chronic obstructive pulmonary disease (COPD)
is a progressive lung disease that makes it difficult to breathe. “Progressive”
means that the disease gets worse over time.
Approximately 12 million people in the United
States have been diagnosed with COPD. Many more may be affected and not know
they have it. According to the Centers for Disease Control and Prevention
(CDC), COPD is the fourth leading cause of death in the United States. Its
prevalence increases with age. Men are more likely to have the disease, but the
death rate for men and women is about the same.
The most common cause of COPD is smoking. The
two main forms of COPD are chronic bronchitis and emphysema. Many people have a
combination of both.
How the Lungs Work
To better understand COPD, it will help to
understand how the lungs work. Every time you breathe in, air passes through
your windpipe and into your bronchial tubes. In your lungs, these bronchial
tubes branch off into thousands of smaller tubes called bronchioles. At the
ends of the bronchioles are air sacs called alveoli. These air sacs are like
little balloons. When you breathe in, they stretch and fill with air. When you
breathe out, they shrink back down.
In the walls of the air sacs are tiny blood
vessels called capillaries. When the air sacs fill with air, oxygen goes into
the capillaries to be carried through your blood stream to all parts of your
body. At the same time, carbon dioxide (a waste material) passes out of the
capillaries into the air sacs. Then you breathe it out.
How COPD Affects Breathing
COPD causes the
following changes in your lungs and airways:
- air sacs and airways lose
their ability to stretch
- the walls of the air sacs
- the walls of the airways
become thickened and inflamed
- airways become clogged with
If you have COPD, you may have one or more of
these changes in your lungs. These changes reduce the flow of air in and out of
your lungs. This deprives your body of much-needed oxygen.
Forms of COPD
There are two main forms of COPD.
Chronic bronchitis: This is chronic inflammation
of the air passages with airflow obstruction. It involves a long-term cough
with mucus. Long term means most days of the week for at least three months in
two successive years.
Emphysema involves destruction of the lung
tissue, specifically the alveoli.
Both forms of COPD cause damage to your
airways and interfere with the absorption of oxygen and the release of carbon
Outlook for COPD
There is no cure for COPD, and doctors are
not able to reverse the damage it causes. Over time, ordinary tasks may become
more difficult. However, with treatment and lifestyle changes, you can slow the
progress of the disease so that you can feel better and stay more active.