Inhaled furosemide does not alleviate respiratory effort during flow-limited exercise in healthy subjects.

Expiratory muscle loading results in increased perception of respiratory effort; this response is mediated by non-vagal reflexes originating in the chest wall. Furosemide, due to its vagal effect, might not affect the perception of respiratory effort during expiratory flow-limited incremental exercise. In this study, we compared in nine healthy subjects the following determinants of exercise performance such as respiratory effort (Borg), workload (W'), ventilation (V'E), tidal volume (VT), respiratory frequency (f), and mean inspiratory flow (VT/TI), an index of central respiratory drive, during either standard incremental cycling exercise, or expiratory flow-limited incremental exercise.