Chronic Obstructive Pulmonary Disease (COPD) encompasses conditions such as emphysema and chronic bronchitis. Emphysema is characterized by damage to the alveoli (air sacs) and bronchi in the lungs. These damaged and weakened air sacs hinder the efficient transfer of oxygen from the air to the blood. As the disease progresses and damage to the air sacs increases, individuals with COPD may experience shortness of breath even at rest. Chronic bronchitis, on the other hand, refers to the inflammation of the bronchi. While healthy lungs normally produce a small amount of fluid, chronic bronchitis leads to excessive mucus production, resulting in an increase in phlegm.