The best way to monitor your asthma is with a peak flow meter, which is used every morning and evening to measure the maximum rate at which you can exhale in litres per minute. The reading indicates whether your airways are narrowed. Plotted on a chart, your peak flow results show how effectively your asthma is being controlled. You can then adjust your treatment, following advice given to you previously by your doctor.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.