Date of Graduation


Document Type


Degree Name

Bachelor of Science

Degree Level



Health, Human Performance and Recreation


Ganio, Matthew S

Committee Member/Reader

Fort, Izna

Committee Member/Second Reader

Kavouras, Stavros A


Despite the necessity of euhydration, an optimal, user-friendly, accurate hydration assessment technique fails to exist for the general population. The primary reason for this study is to validate a new hydration assessment technique, which utilizes no equipment or technical expertise to administer. We hypothesize that the number of urine voids over 24-hrs will correlate to hydration status. We used an observational research design in the field, recruiting fifty healthy individuals (n=24 females) 18-39 years old from the Northwest Arkansas area. Age 22±4 years, body mass 75.01±17 kg, height 168.6±22.6 cm, body fat 20.4±9 %. Individuals abstained from caffeine and alcohol during the experiment. Participants were educated on how to record diet, fluid intake, and void output measurements. For 24-hours participants voided at a normal urge (Athwal et al., 2001) into a standard medical-grade container. Fluid and food intake were ad libitum and recorded. Volume, time, and urge of each void were measured. Total 24-hr urine volume, osmolality, specific gravity (USG), and color were also measured. Subjects were classified as euhydrated (USG<1.021) or hypohydrated (USG≥1.021). As hypothesized, void number correlated to hydration status as identified by USG (r=0.375, P < 0001), and osmolality (r=0.383, P < 0.001). Euhydrated (n = 41) versus dehydrated (n = 6) individuals had more voids (6 ± 2 versus 4 ± 1, respectively, P = 0.027), greater 24-hr urine volume (2007 ± 863 versus 1193 ± 434 ml, P < 0.001), lower urine color (2 ± 1 versus 4 ± 1, P < 0.001), lower USG (1.012 ± 0.004 versus 1.023 ± 0.003, P < 0.001), and lower osmolality (431 ± 143 versus 841 ± 137 mOsm/kgH20, P < 0.001). This research shows that void number positively increases with 24-hour void volume and other makers of hydration status. This indicates that individuals with higher void numbers are more hydrated than those with lower void numbers. Using void number as a hydration biomarker could be an optimal hydration biomarker for the general public, considering it is as simple as counting void numbers over a 24-hr periods. Future studies should investigate individuals with greater differences in hydration status. In addition, this study observed a wide range of individuals; more specific samples sizes (e. g. gender, ethnicity, age, etc.) could show that the number of voids indicating euhydration depends on the population.