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Using a Peak Flow Meter

Hand holding peak flow meter with marker set at bottom.

Woman with peak flow meter in mouth, blowing into it.

Hand holding peak flow meter with marker at number to look at.

A peak flow meter measures how fast you can push air out of your lungs. This tells you how well you are controlling your asthma. Measure your peak flow as many times a day as your healthcare provider tells you to. Long-term daily monitoring with peak flow measurements has been shown to be helpful in the management of asthma.

How to Use a Peak Flow Meter

Step 1:

  • Move the marker to 0, or to the lowest number on the scale.

  • Stand. (If you can’t stand, be sure to sit up straight.) Make sure you’re in the same position each time you test.

Step 2:

  • Take as deep a breath as you can.

  • Put the mouthpiece of the meter in your mouth, between your teeth. Close your lips tightly around it. Be sure your tongue does not block the opening.

  • Blow into the mouthpiece once, as hard and as fast as you can.

Step 3:

  • Take the meter out of your mouth.

  • Look at the marker. It will have moved along the numbered scale. Write this number down.

  • Move the marker back to 0, or to the lowest number on the scale.

  • Repeat the test 2 more times.

  • Record the highest of the 3 numbers in your book.

Determining Your Personal Best

Your personal best is your highest peak flow number during 2 weeks with no symptoms. Other peak flow results are compared to the personal best. This helps show how you’re doing over time. To find your personal best:

  • Step 1: Keep track of peak flow numbers during a period of 2 to 3 weeks. Do this when you feel healthy and are not having any asthma symptoms.

  • Step 2: Monitor at least twice a day—when you wake up and between 6 p.m. and 8 p.m., or as directed by your healthcare provider.

Online Medical Reviewer: Berry, Judith, PhD, APRN
Online Medical Reviewer: Hanrahan, John, MD
Last Review Date: 11/19/2012
© 2000-2014 Krames StayWell, 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.