Ways to measure lung capacity at home

Spirometry is the recommended lung function test for the diagnosis and monitoring of asthma and other respiratory conditions like chronic obstructive pulmonary disease (COPD).

Health authorities have indicated lung function testing, like spirometry, poses more risk at the moment than benefit, due to the potential spread of Coronavirus. As a result, lung function clinics are closing or have reduced activity at this time to help limit risk.

Is there another way to measure my lung function?

Peak flow monitoring is done with a peak flow meter. It measures the maximum (or peak) speed at which you can blow air out of your lungs. This gives a general idea of how narrow your airways are. It can also show how much your airways are changing over time if you measure your peak flow each day.

Peak flow monitoring is not the same as spirometry and is only a guide.

Peak flow monitoring cannot be used instead of spirometry to confirm whether you have asthma.

Should I start monitoring my peak flow?

Discuss peak flow monitoring with your doctor first.

Doctors will be looking at your reported symptoms of asthma and your asthma control to manage your treatment and to generate a written Asthma Action Plan for you to use at home.

Under direction of your doctor, regularly checking and recording your lung capacity at home by using a peak flow meter may assist your doctor to gauge your asthma control and make changes to your treatments, particularly when there is limited or no access to lung function testing.

Peak flow monitoring can be particularly helpful for people with more severe or difficult-to-control asthma, and those who are having difficulty in working out when they have symptoms, particularly with shortness of breath.

Peak flow monitoring and guidelines for monitoring need to be included in your written Asthma Action Plan to be an effective tool for managing your asthma.

Remember. when monitoring is recommended, it is usually done in addition to reviewing asthma symptoms and frequency of reliever medication use.

Logging accurate peak flow measurements

Reliable records will help your doctor make an accurate assessment of your asthma along with a record of asthma symptoms and reliever use, to adjust your treatment regimen.

Here’s what you can do:

  1. Use this helpful log developed by the National Asthma Council Australia and Woolcock Institute for logging your lung capacity using a Peak flow meter: Peak flow chart
  2. Using a chart is more useful than just written down as a list of numbers.
  3. Take regular readings at the same time each day rather than one-off readings
  4. Put in the same amount of effort when blowing into the meter each time
  5. Use the correct technique (see at end)
  6. You will need to find your ‘best’ test score or personal best

What should my lung capacity score be?

It’s important to talk with your doctor first before moving ahead with using a peak flow meter, ensuring your optimal score and what to do if the results drop below, are clearly documented on your written Asthma Action Plan.

Your score should be based on what your personal best peak flow measurement would be. This needs to be worked out with your doctor.

If your score is lower than normal, this can mean your airways are narrower than usual. When your airways are open with no swelling or irritation, the score should be the same or close to the same as your best score.

Everyone will have a different best score, as it depends on an individuals height, age and gender.

If you are feeling unwell despite good peak flow test results, follow the instructions on your Asthma Action Plan or see your doctor.

Who can use a peak flow meter?

Peak flow monitoring is not recommended for children under 12 years. In most children with asthma, change in symptoms is as effective as peak flow monitoring for demonstrating that their asthma is getting worse.

Other ways to test your asthma control to help you and your doctor

Doctors will also be looking at your symptoms of asthma and your asthma control, to manage your treatment and plans at home. Completing the Asthma Control Test on our website can also assist your doctor in determining your level of asthma control. Take the test here and let your doctor know the result at your next asthma review appointment.

You can also call 1800 ASTHMA (1800 278 462) to speak with an Asthma Educator to assist you in improving your asthma control or book a call back here.

 Stop the spread when using a peak flow meter

When using a peak flow meter at home, ensure no one else is in the room if you have Coronavirus or other viral infection. Do not share your peak flow meter with others in the household and use the same peak flow meter each time for accuracy. Wash after each use.

Peak flow technique

You should talk to your doctor or pharmacist about technique when this is written into your Asthma Action Plan. For a refresher, see below.

  1. Attach mouthpiece at the end of the peak flow meter, if it has a separate mouthpiece.
  2. Hold the peak flow meter so that the marker is facing upwards and the marker is on zero (0)
  3. Take a big breath whilst standing upright
  4. Place into mouth with lips tightly around mouthpiece, keep holding the meter horizontal
  5. Blow hard and fast for 2-3 seconds until your lungs are completely empty
  6. Read score
  7. Put marker to zero and repeat 2 or 3 more times.
  8. Record the best 3 readings on the peak flow chart.