Role of the nasal airway in regulation of airway resistance during hypercapnia and exercise. Second-Place Resident Award at 1982 Research Forum.

Posterior mask rhinomanometry was used to measure nasal resistance during exercise and hypercapnia in 10 healthy adult volunteers. Exercise was produced by peddling a stationary bicycle at three loads. Hypercapnia was produced by breathing O2 mixtures containing 5%, 6%, and 8% CO2. The results showed that nasal resistance decreases linearly as expired CO2 levels and exercise levels increase, minute ventilation increases linearly as expired CO2 levels and exercise levels increase, and nasal resistance varies inversely with minute ventilation during both hypercapnia and exercise. The constant relationship between nasal resistance and minute ventilation during hypercapnia and exercise suggests that nasal resistance is regulated by the respiratory center to match the level of respiratory demand.