There are major reasons for testing acute bronchoreversibility in clinical practice. For instance, finding large increments in FEV1 > 400 mL is of great value to confirm the diagnosis of asthma and support therapy. Evaluating whether airflow obstruction is still reversible is also important, even though normal acute responses do not predict effects of chronic treatment and in no case preclude trials with bronchoactive medications. Drs Hansen and Porszasz1 suggest that with respect to the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines,2 the perceptive threshold is more suitable for evaluating bronchoreversibility. We will try to convince our readers that exploring lung mechanics with various functional parameters capable of identifying the fundamental and complex changes with bronchodilation is more important than debating the concept of threshold.