A lung function test measures how well your lungs are working, helping your doctor diagnose the cause and severity of any problems with your breathing.
The U.S. National Heart Lung and Blood Institute says the test is designed to show:
- The amount of air that you can breathe into your lungs to see if it’s in the normal range.
- The amount of air that you can exhale from your lungs, and how quickly you can do it.
- The ability of your lungs to bring oxygen to your blood.
- How strong the muscles that help you breathe are.