Forced expiratory volume / forced vital capacity ratio in one second

Exhaling force for one second is the amount of breath exhaling at the fastest speed at the end of deep inhalation. The ratio of forced expiratory volume in one second to the predicted value of forced vital capacity can reflect the type and degree of ventilation disorder. The normal person's forced exhalation volume per second = forced vital capacity. Exhale forcefully in one second when there is airway obstruction