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Peak flow at home
peak flow meter · peak expiratory flow · PEF · asthma diary
A peak flow meter is a small device you blow into hard. It shows how open your airways are right now.
Mostly for asthma: to track your breathing at home and notice when it gets worse in time.
⏱ Duration: one measurement takes about a minute, usually morning and evening
Be sure to tell your doctor
How to prepare
- Timing. It is usually measured morning and evening, at the same times. Your doctor will set the schedule.
- Medicines. It is usually measured before using your inhaler. Ask your doctor. Do not change your treatment on your own.
- Diary. Write your results in a notebook or an app.
What to bring
- Your peak flow meter
- Your measurement diary
- Your inhalers
How it goes
- Set the meter's pointer to zero
- Stand or sit up straight
- Take a deep breath in
- Seal your lips tightly around the mouthpiece
- Blow out as hard and fast as you can
- Repeat 3 times and write down the best result
What you'll feel
- It does not hurt
- Sometimes blowing hard causes a cough or slight dizziness
Afterwards
- Compare your results with your normal range
- Show your diary to the doctor at your visit
- Your doctor may give you a plan: what to do when your results drop
Contact a doctor straight away if
- Your result has dropped a lot and the inhaler does not help: call emergency services
- It is hard to talk, or your lips turn blue: call emergency services
Common questions
What result is normal?
Everyone's normal is different. It is based on your personal best. Your doctor will explain your zones.
How many times should I blow?
Usually 3 times in a row. Write down the best one.