Shortness of breath (dyspnea)

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Shortness of breath (dyspnea) is a feeling of breathlessness or discomfort while breathing. People who have shortness of breath often say it feels like they can’t get enough air or they can't catch their breath.

People with cancer may have shortness of breath from the cancer and its treatments or other conditions. It’s common in people with lung cancer, mesothelioma and cancer that started in another part of the body and has spread to the lungs (called lung metastases). Many people with advanced cancer also have shortness of breath.


Shortness of breath can be caused by:

  • a blocked airway, such as when a tumour blocks or puts pressure on structures around an airway
  • narrowing of the airway (called bronchospasm)
  • side effects of radiation therapy, such as damage and inflammation to the lungs (called radiation pneumonitis)
  • side effects of chemotherapy, surgery, targeted therapy and other cancer treatments
  • a buildup of fluid in the space between the lungs and chest wall (called pleural effusion)
  • a buildup of fluid around the heart (called pericardial effusion)
  • fluid in the abdomen (called ascites)
  • blood clots in the lungs (called a pulmonary embolism)
  • superior vena cava syndrome
  • low levels of oxygen in the blood (called hypoxemia)
  • low red blood cell count (called anemia)
  • lung infection and inflammation (called pneumonia)
  • lung diseases such as asthma, emphysema and chronic obstructive pulmonary disease (COPD)
  • heart problems such as congestive heart failure or abnormal heart beats
  • smoking
  • anxiety and stress


Symptoms of shortness of breath can vary depending on their cause and other factors. Signs and symptoms of shortness of breath include:

  • trouble catching your breath
  • feeling like you have to work hard to breathe or you can't get enough air
  • pain, discomfort or tightness in the chest
  • faster breathing or heartbeat or both
  • wheezing
  • feeling panicked or anxious
  • pale or blue-looking skin, especially around the fingernails and mouth
  • cold, clammy skin

If symptoms get worse or don’t go away, report them to your doctor or healthcare team without waiting for your next scheduled appointment.


Your healthcare team will try to find the cause of shortness of breath so they know how to manage it. A health history is usually done, and members of the healthcare team often ask questions about your symptoms, past medical problems, if you smoke, and the medicines and treatments you are taking. They will also ask about your shortness of breath, including when you have it and what makes it worse. A physical exam will be done, including listening to your lungs and checking your temperature, blood pressure, pulse and oxygen levels.

You may need to have the following tests.

A complete blood count (CBC) is used to check for anemia and infection.

An x-ray of the chest is done to check for pneumonia or pleural effusion.

A CT scan of the chest is done to check for tumours and blood clots.

Pulmonary function tests are done to measure how well the lungs are working, to check for a blocked airway and to check for low levels of oxygen in the blood. These may include an oxygen saturation test at rest and after walking for 6 minutes. Other tests may include spirometry and diffusing capacity, which measures how fast oxygen in the air passes through the lung membrane into the blood.

A bronchoscopy is done to diagnose problems in the windpipe and airways.

An electrocardiogram (ECG) is done to check the health of the heart.

Find out more about these tests and procedures.

Managing shortness of breath

Shortness of breath is best managed by treating the cause. Once the cause is known, your healthcare team can suggest ways to manage shortness of breath.

Self-care and complementary therapies

Several self-care techniques and non-drug complementary therapies can be used to help manage shortness of breath. The following may help:

  • Different positions may help you breathe easier. You can try sitting upright and leaning forward slightly. You can also try using pillows to prop up your head and upper body when you are sleeping.

  • Controlled or pursed-lip breathing can help make each breath you take more effective. Breathe in (inhale) through your nose and hold your breath for 2 counts. Breathe out (exhale) slowly through pursed (puckered) lips. This will feel like you are whistling. Exhale for 4 counts. It's important to breathe out for longer than you breathe in.

  • Relaxation exercises or meditation can help ease anxiety when you have trouble breathing. Ask your healthcare team for books or videos that may be helpful.

  • Planning your daily activities ahead of time can help you save energy. Take regular rest breaks, especially during activities that tend to cause shortness of breath.

  • Sitting near an open window or in front of a fan can help you get extra air. Opening a window or lowering the room temperature may also help because cooler air is easier to breathe.

  • Quitting smoking and avoiding second-hand smoke can help you breathe easier. If you smoke, get help to quit. Find out more about ways to quit.

Ask your healthcare team for other ways you can cope with shortness of breath.


Medicines are commonly used to manage shortness of breath. They are usually given orally (as a pill by mouth) or intravenously (through a needle into a vein). Some medicines can be inhaled as a fine mist of liquid through a device called a nebulizer.

Medicines that may be used to manage shortness of breath include:

  • opioids (pain medicines) such as morphine (MS Contin, Statex)
  • anti-anxiety medicines such as lorazepam (Ativan)
  • corticosteroids
  • such as dexamethasone or prednisone
  • medicines that open your airways (called bronchodilators), which are given through an inhaler or nebulizer
  • antibiotics for pneumonia or other infections
  • blood thinners (anticoagulants) for blood clots
  • diuretics or other drugs for heart problems

Oxygen therapy

Oxygen therapy is a treatment that gives you extra oxygen. It makes sure you get enough oxygen if you have shortness of breath. You breathe the oxygen in through a mask over your mouth or through tubes in your nostrils. Oxygen therapy is usually only helpful if you have low levels of oxygen in your blood.

Other treatments

The healthcare team may offer the following treatments to help manage shortness of breath.

A thoracentesis may be used to drain an abnormal buildup of fluid in the space between the lungs and chest wall. This space is called the pleural cavity. The doctor inserts a hollow needle through the skin into the pleural cavity after freezing your skin with a local anesthetic. The doctor uses the needle to drain extra fluid from the chest. Find out more about a thoracentesis.

A tunnelled catheter may be used to drain fluid in your pleural cavity if the fluid builds up rapidly after a thoracentesis. Under a local freezing, the doctor inserts a small soft silicone catheter (hollow needle or plastic tube) into the pleural cavity and tunnels the catheter underneath the skin to come out a few inches away. The catheter allows repeat drainages at home by a nurse 2 to 3 times a week until the fluid dries up. The catheter is then removed.

A paracentesis may be used to drain an abnormal buildup of fluid in the abdomen (called ascites). The doctor inserts a catheter through the skin into the abdomen. The doctor uses the needle to drain extra fluid from the abdomen. Find out more about a paracentesis and ascites.

A stent placement may be done when an airway is blocked or narrowed. This can happen when a tumour grows inside the airway or puts pressure on structures around the airway. A stent is a small tube that can be placed inside an airway to hold it open. The doctor inserts it into the airway using a bronchoscopy. Find out more about a bronchoscopy.

A blood transfusion may be done if red blood cell counts are low. Find out more about a blood transfusion.

Cancer treatments may be used to help shrink and control the cancer that is growing in the lungs and airways. These treatments include radiation therapy, chemotherapy or laser therapy.

Expert review and references

  • Stephen Lam, MD, FRCPC

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