Responses to progressive exercise in subjects with chronic dyspnea and inspiratory muscle weakness

Introduction Inspiratory muscle weakness (IMW) is a potential cause of exertional dyspnea frequently under‐appreciated in clinical practice. Cardiopulmonary exercise testing (CPET) is usually requested as part of the work‐up for unexplained breathlessness, but the specific pattern of exercise responses ascribed to IMW is insufficiently characterized. Objectives To identify the physiological and sensorial responses to progressive exercise in dyspneic patients with IMW without concomitant cardiorespiratory or neuromuscular diseases. Methods Twenty‐three subjects (18 females, 55.2 ± 16.9 years) complaining of chronic daily life dyspnea (mMRC = 3 [2‐3]) plus maximal inspiratory pressure < the lower limit of normal and 12 matched controls performed incremental cycling CPET. FEV1/FVC