COPD, or chronic obstructive pulmonary disease, is a progressive disease that worsens over time. With COPD, a reduced amount of air flows in and out of the airways, making breathing difficult. COPD affects more than fifteen million adults in the United States alone. More than half of people diagnosed are women, and it is the fourth leading cause of death in the United States. Cigarette smoking is the primary cause of COPD. However, up to thirty percent of people with COPD have never smoked. A rare genetic disorder called alpha-1 antitrypsin (AAT) deficiency can also initiate the disease. COPD includes two main conditions: Emphysema and chronic bronchitis. Most people diagnosed with COPD have both. COPD causes coughing that produces large amounts of mucus and phlegm. It can also cause difficulties breathing, shortness of breath, chest tightness, and additional symptoms. Symptoms of COPD often develop slowly but get worse over time, and they can limit your capacity to do routine activities. Severe COPD may prevent you from doing simple activities like walking, cooking, or taking care of yourself. Even though there are no cures, treatments, and lifestyle changes such as quitting smoking can help you feel better, stay more active, and slow the progression of the disease. You may also require oxygen therapy, pulmonary rehabilitation, or medicines to treat complications.