Urinary tract infections (UTIs) disrupt military women’s service obligations and health. Females are more susceptible to UTIs due to their unique anatomical features and hormone fluctuations affecting vaginal flora. During phase 1 of the menstrual cycle (onset of bleeding, menstrual cycle days 1-5), estrogen levels significantly decrease and inhibit the growth of lactobacilli, good bacteria that are essential in warding off harmful bacteria and infections, particularly pathogens of UTIs. To reduce UTI onset, it is recommended to frequently urinate with sufficient urine void volume to facilitate washing out harmful bacteria from the bladder and urethra. While menstruating, increased fluid consumption to support urination frequency and void volume may be critical, as the urethra and urinary tract are more predisposed to pathogenic bacteria found. Yet, there is a lack of research investigating the impact of hydration on urinary tract health during menstruation. The study sought to examine the effects of increased water fluid intake on the uropathogenic bacterial activity of underhydrated menstruating premenopausal females. Thirteen females underwent a 2x2 randomized crossover trial to evaluate the effectiveness of a) additional 1.89 L of water fluid intake and b) maintain habitual fluid intake on two subsequent phase 1 menses. At each phase 1 menses, fluid intake was gathered on days 2 and 5 to determine the fluid amount consumed. First-morning urinations on days 3 and 6 assessed urogenital bacterial activity. Combining data collection days 2 and 5 per intervention (INT) and control (CON), the mean±SD for total fluid intake was INT 2.99±1.05 and CON 1.85±0.89, resulting in a 62% increase, p< 0.001, η2= 0.459. For days 2 and 5, a 48% and 80% increase in total fluid in from CON to INT was found, ps< 0.01. However, only four cultures detected uropathogenic bacteria from four participants, with no patterns between conditions or days, making it difficult to determine the effectiveness of the intervention. Though the intervention results were undetermined, military women’s hydration, menstruation, and urinary tract health remain prominent health concerns. Efforts to assess their fluid consumption and urination behaviors during menstruation and UTI risks are warranted.

A Venn Diagram model has been proposed to assist athletes with self-monitoring daily changes in fluid intake by combining three of the simplest hydration markers: weight, urine color, and thirst (WUT). No study to date has examined relationships between WUT markers and urine hydration indices using a new, recently validated lavatory urine color (LUC) chart. Furthermore, this is the first study to investigate an adaptation of the WUT model for identifying low vs. high urine concentration, which is useful for athletes to determine whether they are drinking enough water on a daily basis. For five consecutive days, n=19 participants collected a first-morning urine sample before assessing body weight and thirst at home. The urine sample was later scored by each participant at the testing site after 3 mL was extracted to measure urine specific gravity (USG). Participants could score thirst as yes (1) or no (0), and urine color as darker than (1) or similar to/lighter than (0) when comparing their sample to the reference color on the LUC chart. The researchers calculated body weight change (%) from a predetermined baseline to score body weight as >-0.5% change (1) or <-0.5% change (0). Combined outcomes for the three assessments were assigned a score of 0, 1, 2, or 3 and categorized in the Venn Diagram. Scores of 0 or 1 suggest euhydration (USG <1.020) and scores of 2 or 3 suggest underhydration (USG >1.020). Median USG was 1.021 (ranging 1.003-1.035). WUT outcomes for all cases were: 5% (score 3), 33% (score 2), 53% (score 1), and 9% (score 0). WUT score 3 had optimal accuracy (100%) and WUT score 2 had fair accuracy (67%) for identifying a high urine concentration, but only 38% of cases were scored in this way. Based on the assumption that scores 2+3 should have USG >1.020 and scores 0+1 should have USG <1.020, the total accuracy of the WUT model to correctly classify urine concentration was 60%. The results indicated that athletes can use this approach to identify high urine concentration by monitoring simple hydration markers, but misclassifications may occur up to 33%.