Slide the marker or arrow on the Peak Flow Meter to the bottom of the numbered scale.
Stand up straight. Take a deep breath (as deep as you can). Put the mouthpiece of the peak flow meter into your mouth, tongue down. Close your lips tightly around the mouthpiece.
In one breath, blow out as hard and as quickly as possible (like you are blowing out candles on a birthday cake). Blow a "fast hard blast" rather than "slowly blowing" until you have emptied out nearly all of the air from your lungs.
The marker should move along the numbered scale. Note the number in your peak flow diary.
A peak flow meter is a portable, inexpensive, hand-held device used to measure how air flows from your lungs in one "fast blast." In other words, the meter measures your ability to push air out of your lungs. A peak flow meter may help you and your healthcare provider identify causes of your asthma at work, home or play. It may help parents to determine what might be triggering their child's asthma.
Page last updated: January 27, 2021