You need to know your personal best peak flow number to help control your asthma. This calculator will determine your Green, Yellow and Red Zones, based on your personal best peak flow number.
Many people with asthma think they have their disease well under control when they don't, say researchers writing in a 2007 issue of the Annals of Allergy, Asthma and Immunology. That's why it's important to regularly review your treatment plan with your health care provider to make sure you understand it.