COPD stands for chronic obstructive pulmonary disease - an umbrella term for a number of conditions, including chronic bronchitis and emphysema, all of which make it harder to breathe. COPD leads to damaged airways in the lungs, causing them to become narrower and making it harder for air to get in and out of the lungs. The word 'chronic' has nothing to do with severity, it simply means the problem is long-term.

Chronic bronchitis: Bronchitis means inflammation of the bronchi; these are the tubes or airways carrying oxygen from the air through the lungs. This inflammation increases mucus production in the airways producing phlegm which makes you cough. Emphysema: This is where the alveoli (air sacs) in the lungs lose their elasticity. This reduces the support to the airways, causing them to narrow and may, if severe, lead to people having difficulty absorbing enough oxygen. This can result in shortness of breath.