There are many ways in which cancer can cause fatigue. The growth of a tumor, in general, can be taxing for your body. Other symptoms of cancer such as shortness of breath, anemia, pain, or a decreased level of oxygen in your blood (hypoxia) can cause fatigue.
A pulmonary function test may take 30 to 60 minutes to complete. This will vary according to the amount of trials necessary for you to get repeatable test results.
What is a Pulmonary Function Test? A Pulmonary Function Test is a series of five different tests that measure the different volumes within your lungs, how easily you can move air in and out of your lungs, and how well your lungs are able to transfer oxygen into the rest of your body. The results of these tests can help your doctor assess how your lungs are functioning at rest.