Try to breathe in faster. 6. When you cannot breathe in any further, hold your breath for at least 3 to 5 seconds. Hold it for longer if you can. You will see the piston slowly fall to the bottom of the spirometer. 7. Once the piston reaches the bottom of the spirometer, breathe out slowly and fully through your mouth.

Here is our beginners’ guide to spirometry. Spirometry is a pulmonary function test that measures how much air a patient is able to exhale and how fast. It is particularly useful in the diagnosis and management of lung conditions like asthma, COPD (chronic obstructive pulmonary disease), or pulmonary fibrosis.

You may be asked to use a spirometer after a surgery, if you have a lung problem or a history of smoking, or if you have been inactive for a long period of time. Use your incentive spirometer as instructed every 1–2 hours while you are awake.

The large column of your incentive spirometer has numbers on it (see Figure 1). These numbers measure the volume of your breath in milliliters (mL) or cubic centimeters (cc). The volume of your breath is how much air you can breathe into your lungs (inhale). For example, if the piston rises to 1500, it means you can inhale 1500 mL or cc of air.