Hyperinflated lungs happen when some air gets trapped in the lungs when breathing out. The trapped air takes up space, so it’s harder to get enough fresh air into the lungs. Over time, the lungs get bigger than usual to make room for new air that’s breathed in. The lungs also get stiff and less stretchy, making it harder to push air out. Hyperinflated lungs can make it difficult to catch your breath. And breathing gets worse during physical activity.

Chronic obstructive pulmonary disease (COPD) often leads to hyperinflated lungs. COPD is a long-term lung disease that makes it hard for air to flow in and out of the lungs. The two most common forms of COPD are emphysema and long-term bronchitis. Often the two conditions happen together.

Certain other lung problems, such as asthma and cystic fibrosis, also can cause hyperinflated lungs.

In some cases, lungs can look hyperinflated on X-rays even if you don’t have a problem with how your lungs work. If it’s not clear what’s causing your hyperinflated lungs, your healthcare professional may suggest more tests. A CT scan of the chest and lung function tests are often done.