What level of FEV1 is expected in a person with Moderate Persistent asthma?

In individuals with Moderate Persistent asthma, the expected level of Forced Expiratory Volume in one second (FEV1) typically falls within the range of 60 to 80% of the predicted value. This classification of asthma severity is based on the frequency of symptoms, nighttime awakenings, and the impact on daily activities, as well as lung function measurements.

The rationale behind this is that Moderate Persistent asthma is characterized by daily symptoms and some limitation in physical activities, indicating a more significant airway obstruction than is observed in Mild Persistent asthma, where FEV1 would be expected to be above 80% of the predicted value. Conversely, in Severe Persistent asthma, FEV1 might fall below 60% of the predicted value due to more intense airway inflammation and obstruction. Thus, the range of 60 - 80% accurately reflects the lung function impairment typically seen in Moderate Persistent asthma.