Asthma is the common name for bronchial asthma. The disease occurs due to the body's reaction to allergens, related to genetic factors and external environmental agents. Currently, the method of measuring peak expiratory flow is a popular test that brings high efficiency in diagnosing and monitoring the treatment of asthma.

During an asthma attack, the muscles of the airways contract, causing the airways to narrow. A peak flow meter can help detect narrowing of the airways hours or even days before any symptoms of asthma appear.