Why it can become very difficult to breathe

COPD can cause breathing to be very difficult. When you cannot breathe out all of the trapped air in your lungs, the way you breathe in will be affected as well. When you have too much air remaining in your lungs from your previous breath, less air can be inhaled into your lungs for the following reasons:²

• Your alveoli cannot move air out.
• Your small airways are narrowed and filled with mucus.

Because air cannot be released properly, your lungs can become over-inflated during activity. This in turn can increase your shortness of breath and limit your ability to perform daily activities.²