title: Accuracy of Urine Color to Detect Equal to or Greater Than 2% Body Mass Loss in Men.
abstract: BACKGROUND
  Clinicians and athletes can benefit from field-expedient measurement tools, such as urine color, to assess hydration state; however, the diagnostic efficacy of this tool has not been established.
  
  
  OBJECTIVE
  To determine the diagnostic accuracy of urine color assessment to distinguish a hypohydrated state (≥2% body mass loss [BML]) from a euhydrated state (<2% BML) after exercise in a hot environment.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Environmental chamber in a laboratory.
  
  
  METHODS
  Twenty-two healthy men (age = 22 ± 3 years, height = 180.4 ± 8.7 cm, mass = 77.9 ± 12.8 kg, body fat = 10.6% ± 4.6%).
  
  
  METHODS
  Participants cycled at 68% ± 6% of their maximal heart rates in a hot environment (36°C ± 1°C) for 5 hours or until 5% BML was achieved. At the point of each 1% BML, we assessed urine color.
  
  
  METHODS
  Diagnostic efficacy of urine color was assessed using receiver operating characteristic curve analysis, sensitivity, specificity, and likelihood ratios.
  
  
  RESULTS
  Urine color was useful as a diagnostic tool to identify hypohydration after exercise in the heat (area under the curve = 0.951, standard error = 0.022; P < .001). A urine color of 5 or greater identified BML ≥2% with 88.9% sensitivity and 84.8% specificity (positive likelihood ratio = 5.87, negative likelihood ratio = 0.13).
  
  
  CONCLUSIONS
  Under the conditions of acute dehydration due to exercise in a hot environment, urine color assessment can be a valid, practical, inexpensive tool for assessing hydration status. Researchers should examine the utility of urine color to identify a hypohydrated state under different BML conditions.
authors.affiliation: Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs.
authors.forename: Amy L
authors.initials: AL
authors.lastname: McKenzie
authors.affiliation: Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs.
authors.forename: Colleen X
authors.initials: CX
authors.lastname: Muñoz
authors.affiliation: Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs.
authors.forename: Lawrence E
authors.initials: LE
authors.lastname: Armstrong
mesh_terms: D015992:Body Mass Index; D003116:Color; D003681:Dehydration / Q000175:diagnosis*; D015444:Exercise / Q000502:physiology*; D006358:Hot Temperature; D006801:Humans; D008297:Male; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014556:Urine; D055815:Young Adult
keywords: diagnostic accuracy; field measurement; hydration; sensitivity; specificity