Normal readings vary, depending on your age, height and gender and can also fluctuate throughout the day by as much as 20%. When monitoring Asthma, a Peak Flow test should be conducted regularly, either daily or multiple times a day. In terms of health & fitness, monthly tests or longer would be adequate for testing progressions and adaptations in lung function.
You can easily test your peak flow yourself, it can be conducted at home with an inexpensive Peak Flow Meter usually for less than £20 available, online via Amazon.co.uk.
You can use the monitoring sheet available for download below to help you track your results and compare against the normal values chart.
The Predicted Peak Flow is the expected ideal value based on your age, height and gender. Your Acceptable range is 80 to 100% of this
Testing your Peak Flow
This is the procedure for conducting a peak flow test.
Required resources
- Peak Flow meter (Sponsored link via Amazon.co.uk)
- Disposable Mouthpieces (Sponsored link via Amazon.co.uk)
Procedure
- Insert the mouthpiece into the meter if not already fitted. Ensure the pointer is set at zero (L/MIN position)
- Hold the Peak Flow Meter so that your fingers are clear of the scale and slot. Do not obstruct the holes at the end of the Peak Flow Meter.
- Stand up if possible. Take a deep breath, place the Peak Flow Meter in the mouth and hold horizontally, closing the lips around the mouthpiece, then blow as hard and as fast as you can. Please note that any coughing or spitting into the mouthpiece will adversely affect your readings and should be avoided.
- Note the number on the scale indicated by the pointer.
- Return the pointer to zero (L/MIN position) and repeat twice more to obtain three readings. Mark the highest of the three readings on your Peak Flow Diary. (see download at bottom of page)
Normal Values Chart
Alternatively, you can use the Peak Flow calculator on the mini wright Peak Flow Meter Website
Result Range
Determining how well you score on the Peak Flow Test is normally compared to the normal ranges shown in the chart above, your range is determined by the percentage of the normal value that you reach for your Age, Sex and Height.
| Range | Percentage Reached of Normal Value | Feedback |
| Excellent (GREEN ZONE) | >95% | A peak flow reading in the green zone indicates that the asthma is under good control. |
| Normal (GREEN ZONE) | 81-95% of Predicted | A peak flow reading in the green zone indicates that the asthma is under good control. |
| Mild Obstruction (YELLOW ZONE) | 66-80% of predicted | Indicates caution. It may mean respiratory airways are narrowing and additional medication may be required. |
| Moderate Obstruction (YELLOW ZONE) | 51-65% of Predicted | Indicates caution. It may mean respiratory airways are narrowing and additional medication may be required. |
| Server Obstruction (RED ZONE) | <50% of predicted | Indicates a medical emergency. Severe airway narrowing may be occurring and immediate action needs to be taken. This would usually involve contacting a doctor or hospital. |
Monitoring Sheets
I have designed a couple of simple sheets that can be used to monitor your Peak Flow on a daily basis, this is useful for charting progressions or regressions in Peak Flow which can be useful for both fitness testing and monitoring of asthma.
7 Weeks Peak Flow Monitoring Sheet
Peak Flow Monitoring Sheet (7 weeks) 56 KB 35 downloads
Sheet to help you record your peak flow over a 7 week period. See Lung Function…14 Day Peak Flow Monitoring Sheet
Peak Flow Monitoring Sheet (14 Day) 53 KB 33 downloads
Peak Flow monitoring sheet to help you record your peak flow over a 14 day period. See Lung…You can easily complete this test at home, all you need is a Mini Wrights Peak Flow Meter (Standard Eu)