About shortness of breath

Shortness of breath happens when you are not taking in enough oxygen and your lungs try to draw in more air to make up for it.  

Difficulty breathing is called dyspnoea (pronounced dis-nee-a).

Between 5 and 7 out of every 10 cancer patients (50% to 70%) have this symptom at some time during their illness. This figure rises to 9 out of 10 (90%) for people who have advanced lung cancer.

How breathing works

When we breathe in through our nose or mouth we draw air into our lungs through the windpipe.

The windpipe divides into 2 airways. These are called the right and left bronchus. One goes to each lung. These further divide into smaller tubes and at the end of these are small air filled sacs called alveoli.

It is here that the oxygen we breathe in passes into the bloodstream. The alveoli also take the waste gas, called carbon dioxide, from the blood so that we can breathe it out. 

The diaphragm

When we breathe normally, we use the diaphragm (pronounced dye-a-fram) and the muscles around our ribs.

The diaphragm is a large sheet of muscle that separates your chest cavity from your abdomen. When we breathe in, it tightens up and pulls downwards, making more space in the chest.

The muscles around the ribs also make more space by pulling the ribcage up and out. The lungs expand to fill the space and air rushes into them.

If you are short of breath, you may also be using muscles in your shoulders and upper chest to help you breathe. You normally use these muscles for heavy lifting and they tire very easily. So breathing in this way can make you more out of breath and drain your energy.

Diagram showing the lungs including the alveoli

Who gets breathless

You are more likely to have breathing problems if you have:

  • lung cancer
  • mesothelioma
  • cancer that has spread to the lung

Other types of cancer can also cause breathing difficulties.

Being short of breath can be very uncomfortable and frightening. It can make you feel very anxious and panicky, which often makes it even harder to catch your breath.

People with cancer can become breathless for many different reasons. Once your doctor finds out the cause of your breathing problems there is usually a type of treatment that will help you.

How breathlessness can affect you

Being short of breath can have a big impact on how much you can do each day.

You may be too breathless to shower, cook, or even take a mouthful of food. People with lung cancer sometimes say they can't do the most basic daily tasks, and find not being able to get their breath very frightening.

You might be worried that your breathlessness means your cancer is getting worse. This might be true, but is not always the case. It is very likely that your doctor can give you some treatment to help your breathing. 

Talk to your doctor as soon as possible if you have signs of breathlessness.
Last reviewed: 
19 Nov 2019
  • Breathlessness in cancer patients
    S Thomas and others
    European Journal of Oncology Nursing, 2011. Volume 15, Issue 5

  • Ross and Wilson's Anatomy and Physiology in Health and Illness (12th edition)
    A Waugh and A Grant
    Elsevier Health Sciences UK, 2014

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