What are the stages of COPD?

Dear Dr. Mahler:

I have moderate, or Stage 2, COPD according to my doctor. However, I don’t understand what the stages mean. Will I  go on to the next stage? How many stages are there? Overall, I am doing pretty good. I am 63 years old and still work 30 hours a week at a convenience store. In the summer I work outside to keep our property in good shape and attractive. Thanks for answering this.

Leo from Bennington, VT

Dear Leo:

The stages of COPD are based on breathing tests.  FEV1, or the forced expiratory volume in one second, is how much air you can exhale (blow out) in one second. The breathing tests should be performed after inhaling a quick acting bronchodilator (albuterol. is usually used).

The forced expiratory volume in one second (FEV1) is shown in the figure.

The forced expiratory volume in one second (FEV1) is shown in the figure.


The FEV1 value is then compared with what is expected, or predicted, for your age, sex, and height. This final value is called post-bronchodilator FEV1 percent predicted. This approach has been used for a long time even though we have major discussions at medical meetings about changing from using breathing test results to using the severity of symptoms (breathing difficulty and coughing).

There are four stages of COPD shown here.

  1.     Mild                         FEV1 80 percent predicted or higher
  2.     Moderate              FEV1 50 – 79 percent predicted
  3.     Severe                    FEV1 30 – 49 percent predicted
  4.     Very severe          FEV1 below 30 percent predicted

It is important to remember that the stages are based on how your lungs are working and not on how you feel or your breathing difficulty. Your stage of COPD may actually get better if you start taking one or more inhaled bronchodilator medications. It is also possible that your COPD will remain stable and you will stay in the moderate stage for a long time. On the other hand, breathing tests may get worse in those with COPD, particularly if you continue to smoke cigarettes or inhale irritants (dust, fumes, fibers) in the air.

It is great that you are active, and I encourage you to continue to lead a healthy life style. Let me know if you have further questions.


Donald A. Mahler, M.D.