Nasal resistance in recumbency and sleep.

Nasal resistances to respiratory airflow were measured by computer-assisted rhinomanometry in 21 adult males without major clinical nasal pathology. Measurements were obtained when seated and repeated on assumption of recumbency and during sleep. Resistance in Pa/cm3/s of subjects (n = 21) increased from a mean (+/- SD) of 0.14 +/- 0.07 in seated posture to 0.35 +/- 0.32 in recumbency. In the majority of subjects the increase was modest and was unaffected by sleep. It is suggested that unrecognized mucosal abnormality with resulting impairment of vascular tone or minor structural deviation of the nasal septum could account for the few cases of marked elevation of nasal resistance we observed in recumbency.