The response of the nasal airway to exercise.

Exercise causes a fall in nasal resistance that may be due to sympathetic vasoconstriction in the nasal mucosa. Other factors potentially involved in the exercise effect on nasal resistance are: increased alae nasi muscle activity, passive redistribution of blood to exercising muscle and away from the nasal mucosa, increased nasal air flow, and hyperventilation. In order to determine the importance of these factors, 6 healthy adults had nasal pressure/flow data collected at rest and after bicycle exercise at 100 to 160 W. Erect exercise with nose breathing, erect exercise with mouth breathing, voluntary isocapnic hyperventilation at the minute volumes achieved during exercise, and supine exercise were performed. The alae nasi muscles were voluntarily activated during pressure/flow measurements. The pressure/flow data were displayed on a logarithmic plot; parallel rightward shifts of this plot indicate falls in nasal resistance mediated by enlargement of the air passage. The position of the plot was defined by the flow rate at which the slope of the logarithmic plot steepens abruptly (Vtr). Erect exercise with nose breathing caused a fall in nasal resistance in all 6 subjects (mean change in Vtr, +14.4 L/min). Exercise mouth breathing and supine exercise caused similar falls in nasal resistance in all subjects (mean change of Vtr, +14.1 and +14.2 L/min, respectively). Voluntary isocapnic hyperventilation had no effect on nasal pressure/flow properties in any subject (mean change in Vtr, -1.3 L/min).(ABSTRACT TRUNCATED AT 250 WORDS)