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You're most likely to get COPD from breathing in something that irritates your lungs, like smoke, for a long time.  But there are other reasons, too, for this condition that makes you feel short of breath.

5 Common Causes of COPD

  1. Smoking. Cigarette smoke is by the far the most common reason people get COPD. You can also get it from tobacco products, like cigar and pipe smoke, especially if you breathe in the smoke.
  2. Secondhand smoke. Even if you don't smoke yourself, you can get COPD from living with a smoker and breathing in the smoke.
  3. Pollution and fumes. You can get COPD from air pollution. Breathing in chemical fumes, dust, or toxic substances at work can also cause it.
  4. Your genes. About 2 to 3 in 100 people with COPD have a defect in their DNA, the code that tells your body how to work properly. This defect is called alpha-1 antitrypsin deficiency or AAT deficiency. Your lungs don't have enough of a protein needed to protect them from damage. This can lead to severe COPD. If you or a family member had serious lung problems -- especially at a young age -- ask your doctor about testing for AAT deficiency. 
  5. Asthma. It's not common, but asthma can lead to COPD. If you don't treat your asthma, over time you can get lifetime damage.


How Does COPD Affect Your Lungs?

Inside your lungs are tiny sacs called alveoli. They fill up like a balloon every time you take a breath. The oxygen in these sacs passes into your bloodstream. Then your lungs push out stale air.

When you have COPD, your lungs don't work normally. Long-term irritation such as from smoke or other pollutants damages them for good.

When this happens, the walls between the aveoli break down. Your airways get swollen and clogged with mucus. It becomes harder to push out the stale air.  You don't get enough fresh oxygen with each breath.

In most cases, this happens very slowly. The symptoms may come on over time. It may be years before you even notice them.