This is a test to see how well your lungs are working. Your lungs are in your chest. When you breathe in, air goes into your lungs.
A clip will be put on your nose so you can only breathe through your mouth. You will be asked to take a very deep breath. Then you will blow it out, through a tube. The person testing you, will tell you to “blow, blow, blow!” as hard as you can, for as long as you can. The tube is hooked up to a machine called a spirometer (Spy-rom-uh-tur). It will tell how much air you can blow out (exhale).