Auris Nasus Larynx 2012;39;48-52
Effect of prehydratation on nasal mucociliary clearance in low relative himidity.
The nasal mucociliary clearance in the upper respiratory tract has been reported to be impaired in a low relative humidity environment. We studied the influence of ingesting an ion supply drink on the nasal mucociliary clearance in a low relative humidity environment.
Fourteen healthy male subjects were studied in three randomized cross-over intervention trials using an ion supply drink, water, and a control condition with no prehydration. After resting in a normal room with a temperature 23℃ and a relative humidity of 50% for 20 minutes, the nasal mucociliary clearance was evaluated using the saccharin granule technique*. After the baseline measurement was taken, the subjects moved to an environmental chamber maintained at a temperature of 23℃ and a relative humidity of 10%, and drank each test beverage at a volume of 6ml/kg body weight. After entering the environmental chamber they rested in a sitting position until the end of the experiment, and the saccharin granule technique was used two and four hours after entering the chamber.
* An evaluation method for the nasal mucociliary transport function as transit time between placing the saccharin on the nasal septal mucosa and the moment when the subject could perceive the taste of sweetness.
In the no fluid (control) trial, a decline in the nasal mucociliary clearance was observed after the subjects entered the environmental chamber. In contrast, a significant suppression of this decline in the nasal mucociliary clearance was observed in the ion supply drink trial. On the other hand, no difference was observed in the water trial.
Adequate hydration using the ion supply drink helped to maintain the nasal mucociliary clearance, which is one of the physical defence systems that are compromised under low relative humidity conditions.