Back
Print 

Peak expiratory flow

Skip Navigation

Top of the page

Peak expiratory flow (PEF) is a measure of how much air a person can exhale while breathing out as hard and fast as possible. PEF is used to evaluate the condition of the airways in people who have asthma or other conditions that affect their ability to breathe.

When the airways become narrowed because of inflammation or disease, the peak expiratory flow drops. Even before symptoms of asthma occur, a decrease in the peak rate can show that the bronchial tubes have narrowed.

Peak expiratory flow may be measured at home using an inexpensive device called a peak flow meter. Or it may be measured in a doctor's office using a spirometer.

Current as of: July 31, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

Current as of: July 31, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.