How to use a peak flow meter at home

Asthma is a variable condition, so the aim of doing peak flows at home is to see if the peak flow varies from morning to evening (diurnal variation), or from one day to another (perhaps triggered by an allergen, running or a viral infection).

To obtain a useful pattern to calculate the diurnal variation, the peak flow must be done:

• Every day, at least twice a day
• At the same time each day, in the morning and evening
• Before taking your asthma medication
• Using the same device
• Using your best effort
• For two weeks

Source: Use your peak flow diary, Asthma UK