How to Use a Peak Flow Meter
Peak flow meters are simple, handheld devices that measure lung performance while breathing. They help track asthma symptoms and can help peopl...

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A peak flow meter is a simple, handheld device used to measure how well the lungs perform while breathing. It’s helpful in tracking asthma and how well treatments build up lung strength.

Asthma patients who use a peak flow meter on a regular basis can tailor their medication to prevent an asthma attack or prevent symptoms from worsening.

While a peak flow meter is appropriate for all ages, devices designed for different ages have different scales. Some digital models automatically track readings, while simpler, inexpensive models give readings that can be recorded in a peak flow diary.

For the most accurate readings, make sure you are using your peak flow meter correctly. Going through the steps with your doctor can ensure accuracy to get the most out of your meter. Your doctor will also tell you when to record your peak flow rate, which is normally in the morning before taking your asthma medication.

Peak Flow Meter | Step-By-Step

  • Connect the mouthpiece to the peak flow meter and move the marker to the bottom of the numbered scale.
  • While standing up, take a deep breath until your lungs are full.
  • With your lips tightly around the mouthpiece of the peak flow meter, exhale once as fast and strongly as you can.
  • Note where the marker stops.
  • Give two more breaths into the peak flow meter and record the highest reading. That is your “peak flow rate.”

A peak flow meter is used in conjunction with colored “zones” to determine the state of your asthma. Green means your condition is stable and you display few asthma symptoms. Yellow, which is 50 to 80 of your personal best peak flow rate, means you have some signs of distress such as coughing or wheezing. The red zone is dangerous and constitutes an emergency where medication is needed immediately. 

Written by: Brian Krans
Edited by:
Medically Reviewed by:
Published: Jul 29, 2010
Published By: Healthline Networks, Inc.
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