The centerpiece of your respiratory system, your lungs have the important job of moving oxygen to your blood when you breathe in and removing carbon dioxide, a waste gas, when you breathe out. Millions of Americans are living with lung diseases such as chronic obstructive pulmonary disease (COPD) and asthma, which make breathing difficult and can lead to other breathing-related problems. Experts at the National Heart, Lung, and Blood Institute’s Learn More Breathe Better® program offer tips to help protect your lungs from injury or disease. Learn more at nhlbi.nih.gov/BreatheBetter.