What is the physiological significance of the Forced Expiratory Volume divided byForced Vital Capacity ratio?

The Forced Expiratory Volume (FEV1) divided by Forced Vital Capacity (FVC) ratio is a key measure in pulmonary function tests that helps assess lung function. This ratio indicates the proportion of the total air capacity that can be forcibly exhaled in one second. A normal ratio (typically > 70%) suggests healthy lung function, while a reduced ratio can indicate obstructive lung diseases, such as Asthma or chronic obstructive pulmonary disease (COPD), highlighting airflow limitation. Thus, this ratio is crucial for diagnosing and monitoring respiratory conditions.