forced expiratory volume in one second
FEV1 is the volume of air expelled in the first second of maximal forced expiration from a position of full inspiration.
In normal subjects the fraction of the FVC which can be expelled in one second is:
- >80 % predicted value
- is reduced in obstructive respiratory disease e.g. asthma, mild to moderate chronic obstructive pulmonary disease (COPD)
- is reduced in restrictive respiratory disease e.g. pulmonary fibrosis
- correlates with maximal exercise capacity
- The Practitioner 2005; 249:180-188.
Last reviewed 07/2021