As someone with
asthma, you know how important it is to monitor your
condition. Your doctor may want you to know how well your lungs are "working." Is their ability
to move air in and out staying the same, or is it getting better or
When you monitor your asthma, you can control it. When you
control your asthma, you also control your life-you do what you want to do, and
your asthma does not limit you.
have never used a peak flow meter, talk with your doctor about how
to use it correctly, and then practice using it.
Measure your peak expiratory flow (PEF) regularly, even if you are feeling good. PEF is
lowest in the early morning and highest in the afternoon. When you measure your
PEF once a day, it needs to be done first thing in the morning before you use
your asthma medicine.
It's very important to record the results of
your PEF measurements in your asthma diary(What is a PDF document?). This will help you notice changes
in your breathing. Take your asthma diary with you when you see your doctor so you can review it together. It's very important to review the
diary with your doctor whenever you feel your lung function is
Measuring your peak expiratory flow
any gum or food you may have in your mouth.
Then use your peak flow meter to:
have blown into the meter 3 times, take the highest number you received,
and write it in your asthma diary or on another record sheet.
you cough or make a mistake during the testing, do the test over.
Different brands of meters may give different values for results. If you
change meters, you will need to determine your asthma zones using the new
Note: If your peak flow is lower than normal, check your action plan or call your doctor.
ByHealthwise Staff Primary Medical ReviewerJohn Pope, MD - Pediatrics Donald Sproule, MDCM, CCFP - Family Medicine Adam Husney, MD - Family Medicine Specialist Medical ReviewerLora J. Stewart, MD - Allergy and Immunology Elizabeth T. Russo, MD - Internal Medicine