Peak flow

3) How do you use a peak flow meter?

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This is a peak flow meter and I’m going to show you how to use it.

Slide the pointer down to the bottom of the scale.
Lightly hold the meter on its edge in front of you, with the scale away from your hand.

Take as deep a breath in as you can.
Hold your breath. Place the mouthpiece well into your mouth and seal your lips firmly around it.

Blow as hard and as fast as you can for a second or more, being careful not to block the mouthpiece with your tongue or your teeth.

And I’m now going to show you how to do it.

INHALES

EXHALES

Your peak flow reading is show on the scale against the pointer.
Make a note of the reading and slide the pointer back to the bottom of the scale.

Blow in 3 times and make a note of the reading after each time, and then compare the highest score with your action plan.

You will soon get to know your own normal readings.
You should take the peak flow reading twice a day, morning and evening.

If you become unwell, one of the first signs you might notice is a change in your peak flow reading.

If there are big differences between your morning and evening readings, or if you start to wake at night with a cough or a wheeze, this could be a sign that your asthma is worsening and you should seek medical advice.


  • Stand up if possible or sit up straight.
  • Put the pointer to zero.
  • Hold the meter as per manufacturers instructions, ensure your fingers do not obstruct the scale.
  • Breathe in as deeply as possible, seal your lips firmly around the mouthpiece then blow out as hard and as fast as you can (like blowing out a candle).
  • Be careful not to block the hole with your tongue or teeth and try to avoid coughing or spitting into the meter.
  • Your peak flow is shown on the scale against the pointer. Note where it is and slide the pointer back down to the bottom of the scale.
  • You should do this test three times, one after the other. The readings should be about the same.
  • Record the highest of the three blows in your peak flow diary.