Elevation of nasal mucosal temperature increases the ability of the nose to warm and humidify air.

The nose functions to warm and humidify inspired air. The factors that influence these functions have been studied to a limited degree. We have developed a method for measuring the temperature and relative humidity of the air before and after nasal conditioning to study nasal function. In this experiment we studied the effects of raising the mucosal surface temperature by immersion of the feet in warm water. Six subjects (avg. age = 27.0 years) were randomized to immersion of the feet in 30 degrees C and 40 degrees C water. The nasal mucosal temperature increased significantly from the 32.2+/-1.3 degrees C during immersion in the 30 degrees C water to the 33.1+/-1.2 degrees C during immersion in 40 degrees water (p < 0.05). No significant difference in nasal volume was noted between the 30 degrees (17.8+/-4.5 cc) and the 40 degrees (17.7+/-5.3 cc) immersions. There was a significant increase in the conditioning capacity of the nose (as measured by total water content of inspired air) in response to cold-air challenge during the 40 degrees immersion (1669+/-312 mg water) when compared to the 30 degrees immersion (1324+/-152 mg water). From these data we deduce that warming of the nasal mucosa improves the ability of the nose to condition inspired air without a significant change in the volume of the nasal cavity.

Natural and induced allergic responses increase the ability of the nose to warm and humidify air.

BACKGROUND: We have previously shown that subjects with seasonal allergic rhinitis out of season had a reduced ability to warm and humidify air compared with normal subjects. OBJECTIVE: We sought to investigate whether allergic reactions induced by either seasonal exposure or nasal challenge with antigen would decrease the capacity of the nose to condition cold, dry air. METHODS: We performed two prospective studies comparing the effects of allergic inflammation, induced by either seasonal exposure or nasal challenge with antigen, on nasal conditioning capacity (NCC). The total water gradient (WG) across the nose was used to represent the NCC. In the first study, the NCC was measured and compared before and during the allergy season in 10 subjects with seasonal allergic rhinitis. In the second study, 20 subjects with seasonal allergic rhinitis were recruited outside of the allergy season. NCC was measured and compared before and 24 hours after challenge with antigen. RESULTS: In the first study, seasonal allergic subjects in season showed a significant increase in NCC when compared with their preseason baseline (total WG in season: 2050 +/- 138 mg vs total WG preseason: 1524 +/- 100 mg; P <.01). In the second study, antigen challenge led to early-phase and late-phase responses. There was a statistically significant increase in NCC 24 hours after antigen challenge compared with that before antigen challenge (total WG after antigen challenge: 1938 +/- 101 mg vs total WG before antigen challenge: 1648 +/- 84 mg; P =.01). CONCLUSION: Allergic reactions induced by either seasonal exposure or antigen challenge increase the ability of the nose to condition inspired air. We speculate that allergic inflammation increases this ability by changing the perimeter of the nasal cavity.