Variations in nasal resistance in man: a rhinomanometric study of the nasal cycle in 50 human subjects.

The alternating congestion and decongestion of the nasal mucosa, termed the "nasal cycle", was investigated with current mask (posterior) active rhinomanometric techniques. This communication reports variations in nasal resistance in 50 human subjects, each studied for about 7 hours. Approximately 600 resistance values (cm H2O/liter per second) were obtained from each subject. The nasal cycle defined in rhinomanometric terms was that alternating congestion and decongestion of the nasal turbinates which produced a change in pressure and airflow values calculated as resistance (comparing one side with the other) of 20% or greater for two consecutive observations (at least 15 minutes). The data demonstrated that 36 of 50 subjects (12 of 18 males and 24 of 32 females) had at least one nasal cycle during the period of observation.