The effects of an external nasal dilator on the work of breathing during exercise

Effects of an external nasal dilator on the work of breathing was measured during exercise in 14 untrained students (age, 24 $\pm$ 3 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. Measurement of inspiratory elastic work (inew), inspiratory resistive work (inrw), and expiratory resistive work (exrw) was done using an esophageal balloon. Measured variables included VO$\sb2$, V$\rm\sb{E}$, V$\rm\sb{T}$, frequency of breathing (f), inew, inrw, and exrw, (work expressed in joules). There were no significant differences in VO$\sb2$, V$\rm\sb{E}$, V$\rm\sb{T}$ or f between groups ($\rm p>0.05$). No significant difference was found at peak exercise between groups (mean $\pm$ SD; Placebo; inew, $1.1\pm0.6$ J, inrw, $1.4\pm0.8$ J, exrw $2.2\pm1.8$ J; Active; inew, $1.0\pm0.5$ J, inrw, $1.3\pm0.7$ J, exrw, $1.8\pm0.9$ J; $\rm p>0.05$). Wearing an external nasal dilator does not significantly reduce the work of breathing during exercise.