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.
Pulmonary Function Tests. Pulmonary function testing is sometimes called âPFTâ or âbreathing tests.â This series of tests measures several things. It determines the amount of air in your lungs, the amount of air you can inhale into your lungs, and the amount of air you can exhale from your lungs.