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How to Use Your Peak Flow Meter


Take Action!

Ask your doctor to write an action plan for you that tells you:

  • The peak flow numbers for your green, yellow, and red zones. Mark the zones on your peak flow meter with colored tape or a marker.
  • The medicines you should take while in each peak flow zone.

How To Take Your Peak Flow

  1. Move the marker to the bottom of the numbered scale.
  2. Stand up or sit up straight.
  3. Take a deep breath. Fill your lungs all the way.
  4. Hold your breath while you place the mouthpiece in your mouth, between your teeth. Close your lips around it. Do not put your tongue inside the hole.
  5. Blow out as hard and fast as you can. Your peak flow meter will measure how fast you can blow out air.
  6. Write down the number you get. But if you cough or make a mistake, do not write down the number. Do it over again.
  7. Repeat steps 1 through 6 two more times. Write down the highest of the three numbers. This is your peak flow number.
  8. Check to see which peak flow zone your peak flow number is in. Do the actions your doctor told you to do while in that zone.

Your doctor may ask you to write down your peak flow numbers each day. You can do this on a calendar or other paper. This will help you and your doctor see how your asthma is doing over time.

Checking Your Asthma: When To Use Your Peak Flow Meter

  • Every morning when you wake up, before you take medicine. Make this part of your daily routine.
  • When you are having asthma symptoms or an attack. And after taking medicine for the attack. This can tell you how bad your asthma attack is and whether your medicine is working.
  • Any other time your doctor suggests.

If you use more than one peak flow meter (such as at home and at school), be sure that both meters are the same brand.

Source: National Asthma Education and Prevention Program, National Heart, Lung and Blood Institute, National Institutes of Health

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