What Is Peak Flow Monitoring?

A peak flow meter measures how quickly your lungs release air, which, in turn, tells you how well you are breathing. Adults that monitor their peak flow can improve their health and prevent dangerous asthma attacks. Children should use FEV1 scores instead.

It is important for those who have asthma to closely monitor their lungs, breathing, and symptoms. One way of doing this is to use a peak flow meter. A peak flow meter measures how quickly your lungs release air, which, in turn, tells you how well you are breathing. Monitoring your peak flow can improve your health and prevent dangerous asthma attacks.

How to Measure Your Peak Flow

A peak flow meter is a portable device with a tube, an arrow, and numbers. To measure your peak flow, place your lips on the tube, inhale deeply, and then exhale as quickly and as long as you can. The device will measure the volume of air being released from your lungs. 

Understanding Your Peak Flow Readings

For a peak flow rating to be effective, you need to know what the numbers and readings mean. Your doctor will help you figure out how all the numbers and details relate to you personally, but it will help if you know some basic information.

What is a normal peak flow?

Generally speaking, the higher the number, the better. It is important to keep track of the numbers in an asthma action plan (more on that in a minute) so you can see what your highest peak flow rating was over the course of several weeks. You can begin looking for correlations, causations, and determine what might be triggering your symptoms and causing your peak flow rating to decrease.

What happens if your peak flow is low?

After a few tests, your doctor should let you know what your “danger zone” is. Your danger zone is the highest meter number that indicates a need for quick-relief medication, often referred to as "rescue medication". In other words, it tells you what rating necessitates a doctor’s visit or fast action.

Creating an Asthma Action Plan

A written asthma action plan is a helpful tool for monitoring asthma symptoms, triggers, and attacks. In a nutshell, this plan (developed with the aid of your doctor) is a daily “asthma diary” that lists things such as peak flow ratings, asthma flare-ups, rough days, good days, etc. Not only does this help you identify trigger points, but it also provides a great resource for your doctor to refer back to later. It can answer a lot of questions about your condition and even result in more effective treatment.

Instead of Measuring Peak Flow in a Child...

While adults with asthma can use peak flow measurements to monitor their asthma, doctors recommend a different method for children. The method used to measure the breathing of a child with asthma is called an FEV1 score. This stands for Forced Expiratory Volume in the first second.  


What this method measures is the volume of air from the first second of an exhaled breath. This differs from a peak flow measurement in that a long and sustained exhale is not required.  The information gathered from this test is used to help doctors determine the airflow in young children and how to assist their breathing.


Results are determined by comparing and contrasting against a predicted value calculated by the Centers for Disease Control and Prevention.  The test also takes into consideration the results of children of the same age, height, race, and gender. For children, a score above 80% usually means their breathing is within a normal range.


aluna portable spirometry device and iphone game

Testing Your FEV1 At Home

With the aid of modern technology, you can measure FEV1 scores at home. Aluna is an innovative, scientifically-accurate, and portable spirometry device and asthma management platform. It monitors lung function scores. With the companion smartphone app,  the Aluna device safely and accurately collects important spirometry data, measuring lung health. With Aluna, measurements can be collected daily, at home or on-the-go.

If your child lives in California and has been diagnosed with asthma, contact us for more information on how they can participate in the Aluna clinical trial. Get valuable information for you and your child’s doctor regarding their FEV1 scores.

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