title: Reliability of 24-h void frequency as an index of hydration status when euhydrated and hypohydrated.
abstract: Void frequency (VF) is significantly correlated to hydration status, but it is unknown whether VF is reliable when an individual is repeatedly euhydrated (EU) or hypohydrated (HY). The purpose of this study was to test the reliability of VF when individuals were EU or HY on multiple occasions.
  
  
  
  Fourteen males (age 22±2 years, mass 79.1±12.8 kg) completed three EU trials achieved with 24-h ad libitum fluid intake, and 14 males (age 22±2 years, mass 78.6±10.4 kg) completed three HY trials achieved with 24-h fluid restriction. Twenty-four hour urine was collected and analyzed for specific gravity (USG) and VF. Subjects voided at a 'normal urgency' (rated a '2' on a 0-4 perceptual scale) throughout each 24-h period.
  
  
  
  Twenty-four hour USG was greater and VF was lower when HY (1.026±0.003 and 5±2, respectively) versus EU (1.014±0.003 and 7±2; both P<0.05). Intra-class correlations for VF between the three trials at each hydration status were deemed acceptable (0.863 and 0.849 for EU and HY, respectively). Within-subject coefficients of variation for VF were 15±9 and 21±14% for the EU and HY trials.
  
  
  
  VF is a reliable index of 24-h hydration status when healthy young males are EU or HY and voiding at a consistent 'urgency'.
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: M A
authors: MA
authors: Tucker
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: M A
authors: MA
authors: Gonzalez
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: J D
authors: JD
authors: Adams
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: J M
authors: JM
authors: Burchfield
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: N E
authors: NE
authors: Moyen
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: F B
authors: FB
authors: Robinson
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: B A
authors: BA
authors: Schreiber
authors: Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA.
authors: M S
authors: MS
authors: Ganio
mesh_terms: D000704:Analysis of Variance; D004326:Drinking / Q000502:physiology*; D006801:Humans; D008297:Male; D000074267:Organism Hydration Status / Q000502:physiology*; D015203:Reproducibility of Results; D013046:Specific Gravity; D013997:Time Factors; D014554:Urination / Q000502:physiology*; D014556:Urine / Q000502:physiology*; D055815:Young Adult