Hydration Assessment in Males and Females Using the WUT (Weight, Urine Color, and Thirst) Venn Diagram Compared to Blood and Urinary Indices

Objectives: The WUT (weight, urine color, thirst) Venn diagram has been demonstrated as a practical tool for hydration assessment. However, no investigations have examined if there are sex differences in the accuracy of this method. Therefore, the purpose of this study was to explore potential sex differences in the accuracy of the WUT Venn diagram for hydration status determination. Methods: Twelve men (21 &plusmn: 2 years: 81.0 &plusmn: 15.9 kg) and twelve women (22 &plusmn: 3 years: 68.8 &plusmn: 15.2 kg) completed the study. Body mass, urine color, urine specific gravity (USG), urine osmolality (UOSM), thirst level, and plasma osmolality (POSM) were collected at first-morning and afternoon visits for three consecutive days in free-living and euhydrated states. The number of markers indicating dehydration levels were categorized into either 3, 2, 1, or 0 WUT markers. Receiver-operating characteristics analysis calculated the sensitivity and specificity of 1, 2, or 3 hydration markers in detecting dehydration or euhydration. Results: WUT2 and WUT3 resulted in high specificity values in comparison to USG (WUT2&mdash:male: 0.912, female: 0.949: WUT3&mdash:male: 0.991, female: 1.000), UOSM (WUT2&mdash:male: 0.901, female: 0.946: WUT3&mdash:male: 0.991, female: 1.000), and POSM (WUT2&mdash:male: 0.859, female: 0.896 WUT3: male: 0.977, female: 0.991). WUT1 resulted in high sensitivity values compared to USG (male: 0.931, female: 0.857), but varied between sexes for UOSM (male: 0.875, female: 0.794) and POSM (male: 0.469, female:0.536). Conclusions: The WUT Venn diagram accurately detects dehydration when two or three WUT markers are met in both males and females. The WUT Venn diagram accurately assesses hydration status in males and females, thus providing medical personnel and athlete support teams a cost-effective and time-efficient hydration testing tool.