Chronic obstructive lung disease (COPD) describes a group of lung conditions (diseases) that make it difficult to empty the air out of the lungs. This difficulty can lead to shortness of breath (also called breathlessness) or the feeling of being tired. COPD is a word that can be used to describe a person with chronic bronchitis, emphysema or a combination of these. COPD is a different condition from asthma, but it can be difficult to distinguish between COPD and chronic asthma.
Two people may have COPD, but one may have more symptoms of chronic bronchitis while another may have more symptoms of emphysema. It is helpful to understand the difference between the two conditions, as COPD means a person may have some chronic bronchitis as well as emphysema.