Chronic obstructive pulmonary disease (COPD) is a type of obstructive lung disease characterized by long-term poor airflow. The main symptoms include shortness of breath and cough with sputum production. COPD typically worsens over time.[1] Eventually walking up stairs or carrying things will be difficult.[2] Chronic bronchitis and emphysema are older terms used for different types of COPD.[2][3] The term "chronic bronchitis" is still used to define a productive cough that is present for at least three months each year for two years.