Perceptual and respiratory responses to added nasal airway resistance loads in older adults.

The purpose of the present study was to assess breathing behavior under various nasal resistance load conditions and, in particular, to determine whether respiratory responses to added nasal resistance loads occur before the threshold perception of an added load. The participants were 40 older adults who ranged in age from 59 to 82 years. Nasal airflow and resistance were measured with the pressure-flow technique, which was modified to create calibrated resistance loads. Statistical analyses revealed a significant decrease in airflow rate and volume during load conditions both before perceptual detection and at detection of increased resistance in comparison to a "no load" condition. No differences in respiratory behaviors were found between the load condition just before perceptual detection of an increased resistance load and the load condition at detection. The present findings suggest that physiologic responses to changes in the airway environment apparently occur even before there is perceptual recognition that the environment has changed.