A peak flow meter is a portable handheld device used to
measure how well a person with asthma can blow air out of the lungs. (Asthma narrows
the airways, making breathing difficult.) The person blows into the meter and
then checks the reading.
Some people with asthma use a peak flow meter at home to see how well their
asthma is being controlled. The meter can tell if the airways are getting narrow even
before symptoms start.
Peak flow measurements can help people with asthma work with their doctor to identify
approaching asthma flare-ups, develop an asthma treatment plan, and know when
to get medical care.