Peak flow diary

Peak flow diary for printing off

To take a peak flow reading

1. Put the marker to zero.

2. Take a deep breath.

3. Seal your lips around the mouthpiece.

4. Blow as hard and as fast as you can into the device.

5. Note the reading.

6. Repeat three times.

The 'best of the three' is the reading to record on the chart.

What are normal and abnormal peak flow readings?

Normal peak flow readings vary, depending on your age, size, and sex. The range of normal peak flow readings is published on a chart, and doctors and nurses refer to the chart when they check your peak flow reading. In healthy people, peak flow readings vary slightly from time to time. The reading is often slightly higher in the evening compared with the morning.

Peak flow normal values

Below is an example of a two-week diary of peak flow readings done by a child who has quite bad asthma.

Peak flow graph