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Background Whole-body hydration status is associated with several health outcomes, such as dehydration, edema and hypertension, but little is known about the nonclinical determinants. Therefore, we studied the associations of sex, age, body composition, nutrition, and physical activity on several body hydration measures. Methods We assessed sociodemographic variables, dietary habits, and physical activity by questionnaire and body composition by bioelectric impedance analysis (BIA). We compared determinants between the sexes and calculated associations between determinants and BIVA hydration measures by multivariable linear regressions. Results A total of 242 adults from the general population (age 18–94, 47% women) were included. Women were younger, smaller, lighter, and had a smaller BMI (kg/m 2 ) than men ( p  < 0.05). Women had less muscle mass, less visceral fat mass and less extracellular and intracellular water than men ( p  < 0.001). Women showed less intracellular water per extracellular water than men, while men showed higher phase angle values than women (both p  < 0.001). Men had a stronger association of hydration measures with physical activity than women. Both sexes showed a decrease in hydration measures with age. Conclusions Sex, age, body composition, and physical activity influence body hydration. There seem to be differences in body water regulation between the sexes. Especially interesting are factors susceptible to preventive measures such as physical activity.

Background/Objectives: Hypo-hydration is a major health concern that affects performance and is associated with increasing morbidity and growing health care costs. There is an emerging interest in optimizing hydration and identifying how factors such as ingestion rate and beverage composition affect hydration. This study examined three beverages with varying ingestion rates and measured markers of hydration. Methods: Thirty healthy, active participants between the ages of 18 and 45 years were given three different beverages on three separate days. The beverages were of identical volumes (1 L), but differed in the rate of ingestion, carbohydrate content and electrolyte content. Beverage 1 and water alone were both consumed at a metered rate of one liter over four hours, whereas Beverage 2 was used as a positive control and was consumed at a bolus rate of one liter in 30 min. Results: After six hours, Beverage 1 significantly improved markers of hydration compared to water alone or Beverage 2. Beverage 1 decreased cumulative urine output vs. water alone by 32% (absolute difference −0.33 L; CI ± −0.16 to −0.51) and vs. Beverage 2 by 26% (absolute difference −0.26 L; CI ± −0.13 to −0.38). Beverage 1 increased the beverage hydration index vs. water alone by 64% (absolute difference +0.64 L; CI ± 0.36 to 0.92) and vs. Beverage 2 by 48% (absolute difference +0.53 L; CI ± 0.30 to 0.76). Conclusions: Beverage 1 is superior to water alone at improving hydration when it is ingested at similar rates. Moreover, metered ingestion of Beverage 1 improved hydration compared to a bolus ingestion of Beverage 2, this could be due to the dissimilar ingestion rates and/or beverage composition.

This study aimed to assess the feasibility of an educational intervention on hydration behavior in adolescent soccer players. A pilot study of a two-arm, non-randomized controlled cluster trial was conducted. A total of 316 players aged 13–16 agreed to participate. The response variables were the players’ participation in the intervention, their perception of the knowledge acquired, the usefulness and the overall assessment of the intervention. Hydration patterns and acquisition of knowledge on hydration behavior were also assessed. The intervention involved two elements: posters and a web app. A total of 259 adolescents completed the study (intervention group (IG) = 131; control group (CG) = 128). 80.6% of the players responded to the survey assessing the feasibility of the intervention. The mean number of correct answers regarding behavior was significantly higher in the IG (3.54; SD = 1.162) than in the CG (2.64; SD = 1.174) (p < 0.001). The water consumption pattern at all the clubs was ad libitum. Of the players, 10% did not drink any water at all during the game. In conclusion, this intervention has been shown to be feasible for implementation with adolescent soccer players. It suggests that hydration guidelines should be informed by personal factors and that ad libitum water consumption should be avoided.

Introduction The etiology of the end-stage renal disease (ESRD) and the hydration status may be involved in the arterial stiffening process observed in hemodialyzed patients. The ratio between carotid-femoral and carotid-radial pulse wave velocity (PWV ratio) was recently proposed to characterize the patient-specific stiffening process. Aims: to analyze: (1) the PWV-ratio in healthy and hemodialyzed subjects, analyzing potential changes associated to etiologies of the ESRD, (2) the PWV-ratio and hydration status using multiple-frequency bioimpedance and, (3) the effects of hemodialysis on PWV-ratio in a 5-year follow-up. Methods PWV-ratio was evaluated in 151 patients differentiated by the pathology determining their ESRD. Total body fluid (TBF), intra and extra cellular fluid (ICF, ECF) were measured in 65 of these patients using bioelectrical-impedance. The association between arterial, hemodynamic or fluid parameters was analyzed. PWV-ratio was evaluated in a group of patients (n = 25) 5 years later (follow-up study). Results PWV-ratio increased in the ESRD cohort with respect to the control group (1.03 ± 0.23 vs. 1.31 ± 0.37; p < 0.001). PWV-ratio in the diabetic nephropathy group was higher than in all other etiological groups (1.61 ± 0.33; p < 0.05). PWV-ratio was associated with TBF (r = −0.238; p < 0.05), ICF (r = −0.323; p < 0.01), ECF/ICF (r = 0.400; p < 0.001) and ECF/TBF (r = 0.403; p < 0.001). PWV-ratio calculated in ESRD patients in 2007 increased 5 years later (1.14 ± 0.32 vs. 1.43 ± 0.44; p < 0.005). Conclusions PWV-ratio increased the most in patients with diabetic nephropathy. PWV ratio was significantly associated with age and body hydration status, but not with the blood pressure. PWV-ratio could be considered a blood pressure-independent parameter, associated with the age and hydration status of the patient.

Congestive heart failure (CHF) worsening is a worldwide cause of rehospitalization and mortality, specially during the early period after hospitalization. Fluid accumulation plays a key role in the pathophysiology of both acute heart decompensation and disease progression. The effective use of drugs to maintain restored clinical stabilization in recently discharged patients is a difficult task, and it relies on matching the most appropriately tailored therapy to specific clinical profiles. However, no successful treatment has been shown to reduce post-discharge readmission. We evaluated in a case-control study the effectiveness of an early and personalized congestion-guided ambulatory program on medium-term (6 months) compensation in recently discharged CHF patients. Group A (22 patients) underwent a post-discharge close follow-up consisting of: an early clinic visit within 10 days; a second visit within 10 days after the first; and the other visits at month 1, 2, 3 after discharge. Controls (Group B, 21 patients) underwent a conventional ambulatory follow-up only at month 1, 2, 3 after discharge. The ambulatory approach in both groups was based on the monitoring of signs/symptoms of congestion and body weight, body hydration estimation by using bioelectrical impedance analysis (BIA) and laboratory data. This assessment was finalized to tailor furosemide and daily fluid intake at each visit to eliminate clinical or instrumental evidence of persistent congestion relieving the signs and symptoms. At 6 months, Group A was associated with a better clinical compensation (improved hydration state, lower BNP levels and congestion score), an improved quality of life, and reduced re-hospitalizations. We conclude that in CHF the early and personalized ambulatory follow-up based on congestion-guided treatment is effective to optimize management and maintain clinical stability in the post-discharge period.

To assess body hydration and the distribution of the body water compartments in defined populations of patients with inflammatory bowel disease (IBD) compared with those of matched healthy controls. Fifty-two patients with IBD at time of diagnosis (20 patients with Crohn's disease (CD-new) and 32 patients with ulcerative colitis (UC-new)), 40 patients with long-standing CD (CD-long) and 2 matched healthy control groups (n = 52 and n = 40) were recruited for the study. Total body water (TBW) and extracellular water (ECW) were measured by deuterium oxide and bromide dilution, respectively. Intracellular water (ICW) was calculated as TBW-ECW. In addition, hydration of fat-free mass (FFM) and the ECW:ICW ratio were calculated. FFM, body fat (BF) and % body fat (%BF) were assessed by dual energy X-ray absorptiometry. In female IBD patients, the ECW:ICW ratio was significantly (P < 0.05) higher than in controls (CD-new: 0.89+/-0.11 vs 0.79+/-0.08, P < 0.01; UC-new: 0.85+/-0.15 vs 0.77+/-0.10, P < 0.05; CD-long: 0.86+/-0.14 vs 0.80+/-0.10, P < 0.05). In these female patients, the ICW:FFM ratio was significantly (P < 0.05) lower than in controls. Fluid shifts were especially pronounced in female patients with recently diagnosed CD. In male patients with recently diagnosed UC and in those with long-standing CD, body weight, body mass index, BF and %BF were significantly (P < 0.05) lower than in controls. No differences in body hydration or body water distribution were observed between male patients and controls. An altered body water distribution and body hydration was observed in female IBD patients, especially in female patients with recently diagnosed CD.

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To present evidence-based recommendations that promote optimized fluid-maintenance practices for physically active individuals.   Both a lack of adequate fluid replacement (hypohydration) and excessive intake (hyperhydration) can compromise athletic performance and increase health risks. Athletes need access to water to prevent hypohydration during physical activity but must be aware of the risks of overdrinking and hyponatremia. Drinking behavior can be modified by education, accessibility, experience, and palatability. This statement updates practical recommendations regarding fluid-replacement strategies for physically active individuals.   Educate physically active people regarding the benefits of fluid replacement to promote performance and safety and the potential risks of both hypohydration and hyperhydration on health and physical performance. Quantify sweat rates for physically active individuals during exercise in various environments. Work with individuals to develop fluid-replacement practices that promote sufficient but not excessive hydration before, during, and after physical activity.

Increased hydration is recommended as healthy habit with several merits. However, supportive data are sparse. To assess the efficacy of increased daily water intake, we tested the effect of water supplementation on biomarkers in blood, urine, and saliva. Twenty-four healthy Japanese men and 31 healthy Japanese women with fasting blood glucose levels ranging from 90–125 mg/dL were included. An open-label, two-arm, randomized controlled trial was conducted for 12 weeks. Two additional 550 mL bottles of water on top of habitual fluid intake were consumed in the intervention group. The subjects drank one bottle of water (550 mL) within 2 h of waking, and one bottle (550 mL) 2 h before bedtime. Subjects increased mean fluid intake from 1.3 L/day to 2.0 L/day, without changes in total energy intake. Total body water rate increased with associated water supplementation. There were no significant changes in fasting blood glucose and arginine vasopressin levels, but systolic blood pressure was significantly decreased in the intervention group. Furthermore, water supplementation increased body temperature, reduced blood urea nitrogen concentration, and suppressed estimated glomerular filtration rate reduction. Additionally, existence of an intestinal microbiome correlated with decreased systolic blood pressure and increased body temperature. Habitual water supplementation after waking up and before bedtime in healthy subjects with slightly elevated fasting blood glucose levels is not effective in lowering these levels. However, it represents a safe and promising intervention with the potential for lowering blood pressure, increasing body temperature, diluting blood waste materials, and protecting kidney function. Thus, increasing daily water intake could provide several health benefits.