Effects of an external nasal dilator on the work of breathing during exercise

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Abstract
O’KROY, J. A., T. JAMES, J. M. MILLER, D. TOROK, and K. CAMPBELL. Effects of an external nasal dilator on the work of breathing during exercise. Med. Sci. Sports Exerc., Vol. 33, No. 3, 2001, pp. 454–458. The effect of an external nasal dilator on the work of breathing (WOB) was measured during exercise in 14 untrained college students (age, 23 ± 2.7 yr). Two maximal, incremental ergometer tests were performed to exhaustion. Subjects wore a placebo or an active nasal dilator strip, in random order, during each test. An esophageal balloon was placed through each of the subject’s mouth into the esophagus for measurement of inspiratory elastic work (INEW), inspiratory resistive work (INRW), and expiratory resistive work (EXRW). Subjects breathed through a Hans Rudolph® face mask that covered both the mouth and nose during both tests. Measured variables included oxygen uptake (O2), ventilation (E), tidal volume (VT), frequency of breathing (f), INEW, INRW, and EXRW (work expressed in joules). An alpha level was set at P No significant differences were found in INEW, INRW, and EXRW between conditions at 70% of O2max (mean ± SD; Placebo: INEW, 25.6 ± 17.8 J·min−1; INRW, 22.4 ± 15.8 J·min−1; EXRW, 16.7 ± 12.3 J·min−1; Active: INEW, 24.7 ± 12.9 J·min−1; INRW, 19.7 ± 11.9 J·min−1; EXRW, 15.2 ± 8.6 J·min−1;P > 0.05). No difference was found in INEW, INRW, and EXRW at maximal exercise between conditions (mean ± SD; Placebo: INEW, 50.2 ± 29.9 J·min−1; INRW, 67.3 ± 42.3 J·min−1; EXRW, 102.3 ± 78.4 J·min−1; Active: INEW, 45.7 ± 19.6 J·min−1; INRW, 62.6 ± 36.7 J·min−1; EXRW, 86.3 ± 50.9 J·min−1;P > 0.05). There were no differences in O2, E, VT, or f between conditions. Wearing an external nasal dilator does not significantly reduce the work of breathing during exercise.