Chronic Obstructive Pulmonary Disease

Understanding Chronic Lung Disease

Chronic Lung Disease, also known as Chronic Obstructive Pulmonary Disease (COPD) or Chronic Obstructive Airway Disease (COAD), is a term used to refer to chronic respiratory diseases such as chronic bronchitis and emphysema. It is a progressive disease that causes difficulty in breathing. The term "progressive" here means that the disease worsens over time. Under these conditions, the airways become narrowed and limited flow of air to and from the lungs causes a shortness of breath. In chronic bronchitis, there is persistent inflammation of the airways (bronchi) in the lungs. In emphysema, the bronchioles (smaller airways) and alveoli (air sacs) of the lungs are damaged. Most patients with chronic lung disease have a mix of both emphysema and bronchitis. Unlike Asthma, this condition is unfortunately irreversible and usually worsens over time.




Figure A shows the location of the lungs and airways in a healthy body. The inset image shows a detailed cross-section of the bronchioles and alveoli. Figure B shows lungs damaged by chronic lung disease. The inset image shows a detailed cross-section of the damaged bronchioles and alveolar walls.

Image source: National Heart, Lung and Blood Institute 

How common is Chronic Lung Disease?

It is currently the seventh leading cause of death in Singapore. About 2,000 hospitalisations a year are due to lung disease and the numbers are steadily rising.


  • Cough
    A 'wet' cough with phlegm (sputum) is usually the first symptom to develop. In the early stages, this cough is intermittent (on and off). As the condition worsens, the cough gets more persistent and becomes what is commonly referred to as a 'smoker's cough'.
  • Excessive sputum
    The damaged airways produce more mucus than healthy airways. This contributes to the formation of excessive sputum, resulting in a 'wet' cough.
  • Breathlessness (shortness of breath)
    During the initial stage, a patient will experience this symptom only after physical exertion.


Smoking is the main culprit in most cases as it damages the lining of the airways from the lungs and causes the lining to become inflamed. Air pollution including polluted work conditions can also play a part in worsening the patients’ conditions.


When you consult your doctor, he or she will:

  • Determine if you have the symptoms of chronic lung disease (i.e. cough, excessive sputum and breathlessness)
  • Check if you are at risk of developing chronic lung disease (e.g. due to cigarette smoking and exposure to certain environmental toxins)

If you experience any of the above symptoms or belong to the high risk group, you are most likely to be suffering from chronic lung disease.

  • Pulmonary (Lung) Function Testing
    This is the most important tool used to confirm chronic lung disease. It can detect the disease in the early stages when the patient may not show any symptoms. One of the tests requires a patient to breathe into a spirometer machine. The readings from the spirometer will then confirm the presence of chronic lung disease and assess its severity. This test is also useful in monitoring the patient's progress over time and to review the effectiveness of treatment.
  • Chest X-ray
    A chest X-ray is useful to rule out other conditions which may seem like chronic lung disease. It is also useful in detecting the complications of chronic lung disease. However, just a chest X-ray alone cannot confirm the diagnosis of chronic lung disease.


Find out more information from:

Health Promotion Board 

COPD Association  

  1. How does chronic lung disease make it hard to breathe?

There are a few factors causing breathlessness:

  • The airways in your lungs lose their elasticity, making air flow to and from the lungs difficult.
  • The walls between air sacs are destroyed, resulting in fewer, bigger air sacs.
  • The walls of the airways themselves become thick and swollen, causing the airways to narrow. Cells in the walls of the airways product a larger amount of mucus than usual, further blocking the passage.
  2. What are the treatments for chronic lung disease?
If you are currently smoking, the first step you should take is to quit. Although you may already be diagnosed with chronic lung disease, quitting smoking can help to significantly improve the function of your lungs. There are also medications available that can help improve lung function for better breathing.
  3. Is smoking the main cause of chronic lung disease?
Smoking is the cause of most cases (up to 90%). Smoke from cigarette can cause inflammation and damages the lungs, a result which is believed to lead to chronic lung disease.
  4. How can people with chronic lung disease live more comfortable with their condition?
Your healthcare provider can help you live more comfortably with chronic lung disease. Your doctor’s advice and treatment may include quitting smoking, consuming of medication, exercising regularly, obtaining supplemental oxygen and going for vaccination.
  5. Does exercise help?
A mild to moderate workout routine can improve your health. In fact, physical activities can contribute many benefits such as improving muscle tone, increasing energy levels, strengthening the heart, and boosting your self-esteem. You may consult your doctor for a more comprehensive exercise regime.
  6. Are there any breathing techniques that can help me?
Controlling your coughs can help in preserving your energy. Practising pursed lip breathing can also ease shortness of breath. Consult your doctor about which techniques are more effective for you.
  7. Are there diet tips for people with chronic lung disease?
It is important for patients to maintain a healthy diet which helps to provide the additional energy required as breathing gets difficult as well as promoting a better overall well-being. Salty food should be avoided as too much sodium will lead to fluid retention in the body. Try to consume fresh, healthy food such as leafy greens, fruits, veggies, whole grains and proteins.