3.4 Exercise-induced rhinitis
It has been postulated that laborious exercise has a direct negative effect on nasal functioning and can lead to “exercise-induced rhinitis”. In healthy individuals, exercise promotes a decrease in nasal airway resistance due to an increased sympathetic tone upon a rise in the arterial pCO2 42, however, in patients suffering from pre-existing rhinitis, isometric exercise induces conversely an increase in nasal resistance, probably due to an abnormal neurogenic regulation of the nasal mucosa in these patients43. There is also data that strenuous exercise can lead to rhinitis symptoms and nasal inflammatory changes by itself. One study found a nasal neutrophil influx after a 20 km race in combination with an significantly prolonged MCT after the race 44.