How to Use a Peak Flow Meter

July 11, 2013 2 min read

A peak flow meter is a device that is used by people with asthma to measure how well air moves out of the lungs during exhalation. This measurement is called your peak expiratory flow rate (PEFR), a number that details how open the airways are; as asthma gets worse, the PEFR decreases.

If you have asthma, knowing your PEFR is absolutely essential: if you notice your numbers decreasing, you'll know that something is causing your airways to narrow, helping you to learn what triggers your asthma and act quickly in case of an attack. Additionally, when a peak flow meter is used in conjunction with your asthma action plan, you'll be able to better determine when to take your rescue inhaler or other medications. Here's how to use a peak flow meter properly, and ensure you receive the most accurate reading possible.

  1. Peak Flow MeterSlide the marker on the peak flow meter to the bottom of the scale. Hold it so that your fingers are not obstructing the scale.
  2. Stand or sit up straight. Take a deep breath in, place your lips over the mouthpiece, and lightly bite down. Make sure your tongue is not blocking the mouthpiece.
  3. Push the air out of your lungs as quickly and powerfully as possible. To get an idea of how much force you should use, imagine that you are blowing out the candles on a birthday cake that is on the long end of a dinner table.
  4. Take the meter out of your mouth.
  5. Jot down the number that appears on the meter, and then repeat the entire process twice more.
  6. Record the highest of the three numbers. This is your PEFR. Make sure to keep this information handy - in an asthma journal, for example - and pass it along to your primary care physician.

Remember, knowing your PEFR on a good day will help you determine if your lungs are having a bad day. When you notice your readings dwindling below 80% of your personal best, consult your asthma action plan and take more frequent readings - and if symptoms worsen, call your doctor! If you don't have a peak flow meter, do your lungs a favor and check out our selection - this is one device you absolutely need!