Understanding the role of spirometry for lung health

Patient use Incentive Spirometer in Ankur Hospital

Spirometry is a standard pulmonary function test that evaluates how well the lungs work by calculating their breathing capacity. It works by measuring the volume & speed of air inhaled and exhaled by the lungs.

What is spirometry used for?

Spirometry is performed to diagnose chronic lungs conditions like:

  • Asthma
  • Bronchiectasis
  • Emphysema
  • Cystic fibrosis
  • Chronic bronchitis
  • Pulmonary fibrosis
  • Occupational-related lung disorders
  • Chronic obstructive pulmonary disorder (COPD)

For people diagnosed with chronic lung conditions, spirometry may be conducted periodically to evaluate the shape of the lungs and determine the effectiveness of treatment and medication in improving breathing problems. The test may also be performed before a planned operation to decide whether a person’s lung function is adequate to withstand the rigors of surgery.

How to prepare for test

The doctor will provide a few instructions to help an individual prepare for the test. 

Instructions will be:

  • Avoid smoking at least 1 hour before taking the test
  • Avoid intake of alcohol for at least 24 hours before taking the test
  • Avoid wearing tight clothes that may restrict breathing during the test
  • Avoid eating a large meal before the test as it may have an impact on breathing

People on breathing medications such as bronchodilators may be given specific instructions about their use before the test. 

For example, in some cases, a doctor will ask a person to stop using bronchodilators to test their effect on breathing.

Spirometry procedure

A doctor or nurse generally performs a spirometry test at a clinic. The following procedure can expect during the test:

  • The person will be seated during the test. A clip will place on their nose to keep both the nostrils closed.
  • The person will give a tube called a spirometer. They will ask to seal their lips tightly around the mouth of the spirometer.
  • The person will instruct to take a deep breath in, hold it for a few seconds, and then exhale as quickly and forcefully as possible into the spirometer. They will ask to repeat this step at least three times to ensure that the test results are consistent and accurate.
  • If there is more variation between the test results, then the person will be asked to retake the test. The doctor will bring the highest value from three close test readings and the final result.

Nevertheless, if a person exhibits a breathing disorder, the doctor will administer a bronchodilator to open up the lungs after the initial round of tests. Then, they will ask to wait for 15 minutes before doing another test set. Later, the results of the two measurements will compare to determine the bronchodilator’s effect on the airflow.

Interpreting the spirometry test results

Doctors use the following key measurements to interpret the spirometry test results.

Forced Vital Capacity (FVC): The maximum amount of air that a person can exhale forcefully after breathing in as deeply as possible. A lower than standard FVC is indicative of restricted breathing.

Forced expiratory volume (FEV-1): The amount of air a person exhales during the first second of the FVC. A doctor uses FEV-1 reading to determine the severity of breathing problems. Lower FEV-1 reading implies significant obstruction in breathing.

Tidal volume: refers to the average amount of air that moves in and out of the lungs during each respiratory cycle when no extra effort is applied. In an average young adult, the normal tidal volume is approximately 7 mL/kg of body mass.

It is important to note that the results of spirometry testing may vary from person to person. Some factors, including age, gender, height, ethnicity, etc., influence the average spirometry test results.

Side effects and risk

Spirometry is generally considered a safe pulmonary function test. However, a few complications may occur during or after the test. For example, after performing the test, a person may experience dizziness or shortness of breath. In sporadic cases, the test may cause severe breathing problems.

Since the test requires some form of exertion, it is not recommended to people with chronic heart ailments or who recently had a heart attack.

Incentive spirometer

Physicians recommend using an incentive spirometer at home to people who have recently had surgery, people with chronic lung disease, or those with respiratory problems that fill their lungs with fluid.

An incentive spirometer is an equipment used to improve lung function after surgery or a respiratory illness. The device supports lung recovery by helping a person breathe more deeply and fully. The use of an incentive spirometer can also help prevent complications such as pneumonia by keeping the lungs free of fluids.

The procedure of using an incentive spirometer is as follows:

  • Sit at the edge of the bed.
  • Hold the device in an upright position.
  • Tightly cover the mouthpiece with your lips to create a seal.
  • Slowly inhale as deep as you can until the piston in the central column gets to the goal set by your physician.
  • Hold your breath for a minimum of 5 seconds, then breathe out until the piston falls to the bottom of the spirometer.
  • Rest for a few moments and repeat at least ten times per 60 minutes.


Spirometry is a practical and straightforward pulmonary function test used to assess how well the lungs work. It is usually performed to diagnose respiratory conditions such as asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis, pulmonary fibrosis, etc. If the spirometry test yields abnormal results, a physician may likely perform a few other tests, including chest and sinus X-rays and blood tests, to determine whether such respiratory conditions cause breathing problems. The physician may also recommend using an incentive spirometer or respirometer to improve lung function.
For any queries or concerns related to respiratory health, please speak with our Ankur Hospital Team.

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