Pulmonary fibrosis

How does pulmonary fibrosis affect your breathing?

Pulmonary fibrosis scars your lungs and so reduces the efficiency of your breathing.

Scarring causes your lungs to become stiffer and less elastic so they are less able to move and take oxygen from the air you breathe.

Each time you breathe in, you draw air into your nose or mouth, down through your throat and into your windpipe, also called your trachea. Your windpipe splits into two smaller air tubes called bronchi, which go to your lungs. The air passes down the bronchi, which divide again and again, into thousands of smaller airways called bronchioles. 

Diagram of the lungs, airways, bronchioles, and air sacs

The bronchioles have many small air sacs, called alveoli. Inside the air sacs, oxygen moves across paper-thin walls to the capillaries - tiny blood vessels - and into your blood. The air sacs also pick up the waste gas, carbon dioxide from your blood, ready for you to breathe it out.

If you have pulmonary fibrosis, scarring affects the air sacs in your lungs. The air sacs are supported by the interstitium, a network of tissue, a bit like lace. Scarring fills in the gaps between and around the air sacs and limits the amount of oxygen that gets into the blood.

Air sacs of the lungs in pulmonary fibrosis

As scarring increases, your lungs are less able to expand to allow you to take deep breaths and the level of oxygen in your blood can start to drop. Breathing may feel like harder work and you can feel breathless from everyday activities like walking.

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Last medically reviewed: August 2016. Due for review: August 2019

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.