Checking your "peak flow" is one of the best ways to empower yourself and
gain control over your asthma. It can help you make sure your asthma is not
getting worse and can bring you peace of mind.
Asthma is a condition that builds slowly -- it usually does NOT suddenly attack
without warning. One way you know an attack is coming is that symptoms appear
and grow worse. However, a second way is to check your peak flow -- this can
help you to "see an attack coming" and take the appropriate action, sometimes
before you even feel any symptoms. If you are not monitoring your asthma, an
attack can take you by surprise.
What is "peak flow"?
Peak flow is a measurement of how well you can blow air out of your lungs.
If your airways become narrow and blocked due to asthma, you can't blow air
out as well, and your peak flow values drop.
Peak flow is measured at home with a small, inexpensive plastic meter. Several
companies make these meters, and they vary in look and feel. Some peak flow
meters have tabs on the side that you can adjust to match your action plan
zones (green, yellow, red). If your meter does not have these, you can mark
them with colored tape or a marker.
To view an interactive guide on using a peak flow meter, click
You'll need some form of record chart (also called a "log" or "diary") to
write down your peak flow scores. These charts are included with peak flow
meters -- it is a good idea to photocopy the chart and keep the sheets to show
your doctor, who can glance through your whole history of peak flow values
to see how they have changed over time.
A good record chart also will contain a place to note:
- Any signs or symptoms you felt each day,
- Steps you took if you had symptoms or your peak flow dropped,
- Changes the doctor made in your medication, and
- Any asthma triggers you were exposed to.
This information will help make a complete picture of all factors that are
impacting your asthma.
Who should use a peak flow meter?
According to guidelines from the National Institutes of Health, the following
people might benefit from peak flow monitoring:
- Anyone with moderate-to-severe persistent asthma. These people should consider
using a peak flow meter every day or two, even when they are feeling well.
- People who are just starting to work with their doctor to develop a new
treatment plan. A peak flow meter can help determine how well the medications
are working and help the doctor figure out how to fine tune the treatment
- Anyone who has ever had a severe asthma episode (attack).
- Anyone who wants to fully master their asthma management and gain the peace
of mind that comes with it.
Many children under age 5 can't use a peak flow meter well enough to make
the numbers useful, so their asthma must be managed by an adult who needs to
watch carefully for the asthma signs. The age 5 "cutoff" is somewhat arbitrary,
however, and can be adjusted based on the abilities of the individual child.
It's a good idea to start using peak flow meters before age 5 to get the child
used to them, but not to actually rely on them too much for monitoring the
"Both of my children had a little difficulty learning to use the
peak flow meter, but they caught on quickly."
-- Kris, age 41
Review Date: 5/16/2007
Reviewed By: Alan Greene, M.D., F.A.A.P., Department of Pediatrics, Packard Children's Hospital, Stanford University School of Medicine; Chief Medical Officer, A.D.A.M., Inc.
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