Effect of prehydration on nasal mucociliary clearance in low relative humidity

Objective: Nasal mucociliary clearance, which plays an important role in defending the respiratory system, tends to decrease under conditions of low relative humidity (RH). The purpose of this randomized cross-over study was to investigate the preventive effect of prehydration on nasal mucociliary clearance under low RH conditions. Methods: Fourteen young healthy subjects were assigned to three interventions: prehydration (6 ml/kg body weight) using water (W), prehydration using a carbohydrate-electrolyte beverage (CE), and control conditions (Cont) with no prehydration. For each intervention trial, subjects sat for 4 h in an environmental chamber (23 degrees C, 10% RH). Nasal mucociliary clearance was measured by the saccharin transit time (ST). Furthermore, a dry sensation of the mucosa, urine volume, and body weight were measured at the baseline, 2 h and 4 h after entering the environmental chamber, respectively. Results: ST was prolonged under the Cont conditions after entering the environmental chamber. Prehydration with CE led to a significantly lower ST compared to the Cont pretreatment at 2 h, whereas the W trial showed no significance difference in comparison to the Cont values. Conclusion: These results suggest that prehydration with a carbohydrate-electrolyte beverage is therefore beneficial for maintaining better nasal mucociliary clearance at least for 2 h under low RH conditions. (C) 2011 Elsevier Ireland Ltd. All rights reserved.