Study was a randomized double-blinded crossover design in which subjects completed a series of exercises at a constant work rate while using 1) Test noninvasive ventilation (NIOV) system powered by compressed air, 2) Test NIOV system powered by 100% oxygen, 3) nasal cannula oxygen, 4) nothing (Control). Subjects were assessed during constant work rate exercise as reflected by exercise duration, isotime oxygenation (SpO2), and isotime dyspnea score (Borg). Exercise sessions took place over 4 visits with each visit lasting approximately 5 hours.
