title: Effect of prehydration on nasal mucociliary clearance in low relative humidity.
abstract: 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 (6ml/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 4h in an environmental chamber (23°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, 2h and 4h 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 2h, whereas the W trial showed no significance difference in comparison to the Cont values.
  
  
  CONCLUSIONS
  These results suggest that prehydration with a carbohydrate-electrolyte beverage is therefore beneficial for maintaining better nasal mucociliary clearance at least for 2h under low RH conditions.
authors: Saga Nutraceuticals Research Institute1, Otsuka Pharmaceutical Co., Ltd. 5006-5 Omagari, Yoshinogari, Kanzaki, Saga 842-0195, Japan. h_oozawa@research.otsuka.co.jp
authors: Harumi
authors: H
authors: Oozawa
authors: Hiroyuki
authors: H
authors: Kimura
authors: Tsuneyuki
authors: T
authors: Noda
authors: Koichiro
authors: K
authors: Hamada
authors: Taketoshi
authors: T
authors: Morimoto
authors: Yuichi
authors: Y
authors: Majima