TY - JOUR T1 - Are the “critical” inspiratory constraints actually decisive to limit exercise tolerance in COPD? JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00178-2020 VL - 6 IS - 3 SP - 00178-2020 AU - Mathieu Marillier AU - Anne-Catherine Bernard AU - Ricardo Gass AU - Danilo C. Berton AU - Samuel Verges AU - Denis E. O'Donnell AU - J. Alberto Neder Y1 - 2020/07/01 UR - http://openres.ersjournals.com/content/6/3/00178-2020.abstract N2 - Exercise intolerance is characteristically multi-factorial in patients with chronic obstructive pulmonary disease (COPD) [1]. At least in symptomatic patients with moderate-to-severe airflow limitation, higher operating lung volumes assume a relevant role in decreasing patients’ tolerance to sustain “prolonged” exercise. As a consequence of the dynamic increase in the end-expiratory lung volume, tidal volume (VT) occurs close to total lung capacity (TLC), thereby reducing the room for further lung–chest wall expansion. The combination of low dynamic lung compliance and a severely reduced inspiratory reserve volume causes a mismatch between a growing respiratory neural drive and the resulting lung–chest wall displacement [2]. It has been postulated that such critical inspiratory constraints (CIC) lead to a plateau in VT, and a concomitant increase in dyspnoea as a function of ventilation (V′E) [3]. Accordingly, patients change their perception of the uncomfortable respiratory sensations from “laboured breathing” to “insufficient inspiration”, prompting early exercise termination [4].The concept of critical inspiratory constraints is key to the modern understanding of exercise pathophysiology in patients with moderate-to-severe COPD https://bit.ly/2A6bCxD ER -