In this article, we’ll explore what spirometry is, what it measures and how the test can be conducted. We’ll also provide some normative data, provide tips on reliability and validity, and where to buy a spirometer.
What is Spirometry?
Spirometry is a test that evaluates lung function by measuring the amount of air you can exhale and inhale in one forced breath.
By measuring the amount of exhaled and inhaled air while considering three key measures: (1) volume (i.e. the amount of air in the lungs), (2) time and (3) flow (i.e. speed), spirometry can be used to identify if the airways are narrowed and diagnose or monitor conditions that affect the lungs. These include asthma, chronic obstructive pulmonary disease (COPD), and other respiratory disorders. Good lung function means you can get enough oxygen into your body when training or competing.
With the availability of portable devices, spirometry can be conducted in various locations, and when accompanied by proper training, it can be performed by anyone.
What does a Spirometer measure?
A spirometer is a hand-held device where you can record a number of values. These include:
- Forced vital capacity (FVC) – the largest amount of air that you can forcefully exhale.
- Forced expiratory volume (FEV1) – the largest amount of air that you can forcefully exhale in just one second.
- The ratio between FEV1 and FVC (FEV1:FVC) – the percentage of how much your lung capacity is exhaled in just one second. Typically, a normal result is considered at 80%. Normal values are calculated based on your age, height and gender.
You can also use a peak flow metre to measure the forces you expel air from your lungs. It is an easy to use and inexpensive device. However, unlike spirometry, it is basic and can’t give us a deeper understanding of other values.
How to test athletes with a Spirometer
To use a spirometer, it’s important that we first make sure the athlete is in the correct position. They should be:
- Sat upright – there should be no difference in the amount of air expired between a seated and standing position if the athlete maintains an upright posture.
- Feet placed flat on floor with legs uncrossed – we want to minimise the influence of the abdominal and legs during the test.
- Wearing loose clothing – if clothes are too tight, they may restrict airflow during the test, which can lead to lower volume readings.
Now we need to make sure you and the spirometer are prepared:
- Wash your hands and put disposable gloves on – the risk of infection transmission is small but the potential is real.
- Put a disposable mouthpiece on the spirometer (dispose of them appropriately and clean down the surfaces after).
Now that the athlete is in the correct position and you’re all set, let’s look at how we perform the test. There are a number of different techniques, but let’s look at how to perform the test with the peak flow metre, check out the steps below:
- Sit down, with your feet flat on the floor and your chest up right.
- Set the pointer to the initial line closest to the mouthpiece on the scale.
- Hold the peak flow metre horizontally, keeping your fingers away from the measurement scale.
- Breath normally and once you are ready, take a deep breath and tightly seal your lips around the mouthpiece.
- Breath out forcefully and rapidly with maximum effort.
- Once you have completed the forceful and rapid breath out, record your reading and repeat this process.
It’s important that your athlete exhales as hard and as fast as possible, remind them between each trial. Repeat this process three times, and record the highest measurement of the three trials as your peak flow score.
Testing norms for spirometry
Now that we have an athlete’s spirometry result, we can compare their results to help us interpret them. In the table below, we can see athletes’ results for different sports.
If you are concerned about your results, we recommend speaking with your GP or doctor.
Reliability and Validity
Ensuring the reliability and validity of the spirometry results highly relies upon the presence of a trained professional, with a well-maintained spirometer, and the correct execution of the test by the athlete. Here is a couple of steps we can take:
- The individual conducting the test should be well trained in operating the spirometer and effectively demonstrate the process correctly.
- Following the testing procedure each time.
- Maintaining the spirometer, by calibrating the ‘fancy’ spirometers. The hand held peak flow metres can’t be calibrated, but they can be well maintained.
- The athlete should receive clear instructions on how to properly execute the test, and should strive to exhale with maximum force and speed – the athlete’s ability to perform the test correctly will greatly impact the reliability of the result.
Where to buy a Spirometer?
A spirometer can typically be found in a doctor’s surgery, but you can also buy a basic electric hand held machine from amazon and more complex machines such as the MicroLoop from alternative places, with prices ranging from £69 to well over £2,000 respectively.
Alternatives to a Spirometer
A hand held peak flow metre can be bought online from amazon for under £10, or you may be able to get one from your GB or local pharmacy.
Spirometry is a useful measure for detecting early change in disease and provides physiological confirmation for diagnoses. It can also indicate good lung function during exercise.
When performed correctly, it can be used to assess disease progression and response to therapy. With the introduction of portable metres, it can be performed anywhere and by anyone with good training.
Mazic et al (2015) – Respiratory parameters in elite athletes – does sport have an influence?
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