How To Use A Peak Flow Meter

A peak flow meter helps you check how well air flows in and out of your airways. There are several types of peak flow meters. They all work the same way. They all have a mouthpiece and a scale marked with numbers.

By writing down your peak flow results, you can help your doctor make decisions about your treatment.

Track your peak flow readings to:

• Spot the early stages of an attack, so you can treat it fast.



• Know when to get emergency treatment, based on your Asthma Action Plan (PDF Format).



• See how your asthma changes over time. This helps your doctor decide when you should take medicine.



• Learn what triggers your asthma symptoms.

How to use a peak flow meter:

1. Stand or sit up straight.



2. Place the arrow at the bottom of the numbered scale. This is often at 0 (zero).



3. Take a deep breath. Close your lips around the mouthpiece, but keep your tongue away from the opening.



4. Blow out as hard and as fast as you can.



5. Write down the number shown on the scale.



6. Repeat these steps twice.

Follow the cleaning instructions that come with your peak flow meter.

Talk with your doctor, if you have questions about how to use your peak flow meter.

Find your personal best peak flow number

Ask your doctor to help you set your personal best peak flow number. This is the highest number that you can reach over two weeks when you’re not having asthma symptoms. If your doctor suggests it:

• Take peak flow readings when you wake up and at night.


• Take readings before and after you take your quick-relief medicine.


• Keep track of the results, so you can talk about them with your doctor.

The three-zones

What do your peak flow numbers mean? Think of the colors of a traffic light:

Green zone You’ve reached at least 80% of your personal best number. This means all clear. Keep taking your medicines as your doctor tells you to take them. Yellow zone You’re at one half to 80% of your personal best number. This means be careful. Your asthma is getting worse. Your doctor may tell you to raise your dose or change your medicine. Follow your Asthma Action Plan. Or, call your doctor to find out how to get your asthma under control. Red zone You’re at less than one half of your personal best number. This is a medical emergency. Take your quick-relief medicine right away. Call your doctor or go to the emergency room.

NOTE: Readings can vary among different peak flow meters. If you have questions about your peak flow, ask your doctor.