COPD (chronic obstructive pulmonary disease)

What is COPD?

Chronic obstructive pulmonary disease, or COPD, describes a group of lung conditions that make it difficult to empty air out of the lungs because the airways have become narrowed.

On this page:

What does COPD stand for?

Chronic = it’s a long-term condition and does not go away

Obstructive = your airways are narrowed, so it’s harder to breathe out quickly and air gets trapped in your chest

Pulmonary = it affects your lungs

Disease = it’s a medical condition

Two of these lung conditions are long-term (or chronic) bronchitis and emphysema, which can often occur together.

  • Bronchitis means the airways are inflamed and narrowed. People with bronchitis often produce sputum, or phlegm.
  • Emphysema affects the tiny air sacs at the end of the airways in your lungs, where oxygen is taken up into your bloodstream. They break down and the lungs become baggy and full of bigger holes which trap air.

These conditions narrow the airways. This makes it harder to move air in and out as you breathe, and your lungs are less able to take in oxygen and get rid of carbon dioxide.

The airways are lined by muscle and elastic tissue. In a healthy lung, the springy tissue between the airways acts as packing and pulls on the airways to keep them open.

With COPD, the airways are narrowed because:

  • the lung tissue is damaged so there is less pull on the airways
  • mucus blocks part of the airway
  • the airway lining becomes inflamed and swollen

There are treatments to help you breathe more easily and help you keep active, so it’s important to get an early diagnosis.

Diagram showing lungs with and without COPD by the British Lung Foundation


What causes COPD?

COPD usually develops because of long-term damage to your lungs from breathing in a harmful substance, usually cigarette smoke, as well as smoke from other sources and air pollution. Jobs where people are exposed to dust, fumes and chemicals can also contribute to developing COPD.

You’re most likely to develop COPD if you’re over 35 and are, or have been, a smoker or had chest problems as a child.

Some people are more affected than others by breathing in noxious materials. COPD does seem to run in families, so if your parents had chest problems then your own risk is higher.

A rare genetic condition called alpha-1-antitrypsin deficiency makes people very susceptible to develop COPD at a young age.

What’s the difference between COPD and asthma?

With COPD, your airways have become narrowed permanently – inhaled medication can help to open them up to some extent. With asthma, the narrowing of your airways comes and goes, often when you’re exposed to a trigger – something that irritates your airways – such as dust, pollen or tobacco smoke. Inhaled medication can open your airways fully, prevent symptoms and relieve symptoms by relaxing your airways.

So, if your breathlessness and other symptoms are much better on some days than others, or if you often wake up in the night feeling wheezy, it may be that you have asthma.

Because the symptoms are similar and because people who have asthma as children can develop COPD in later life, it is sometimes difficult to distinguish the two conditions. Some people have both COPD and asthma.


What are the symptoms of COPD?

Symptoms include:

  • getting short of breath easily when you do everyday things such as going for a walk or doing housework
  • having a cough that lasts a long time
  • wheezing in cold weather
  • producing more sputum or phlegm than usual

You might get these symptoms all the time, or they might appear or get worse when you have an infection or breathe in smoke or fumes.

If you have COPD that has a severe impact on your breathing, you can lose your appetite, lose weight and find that your ankles swell.

Next: How is COPD diagnosed? >

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Last medically reviewed: September 2019. Due for review: September 2022

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.