Hydration status plays a key role in healthy ageing, and it is potentially affected by several factors, including drug consumption. However, research on this issue to date is scarce, especially in highly vulnerable groups, such as the elderly. We aimed to study the relationship linking hydration status, analysed by means of a validated questionnaire, 24 h urine analysis, body composition assessment, and drug consumption in a sample of old adults. A total of 144 elders were included in the study. Cardiovascular drug consumption was significantly associated with a lower water intake in men (β = -0.282, p = 0.029). Moreover, urinary analysis revealed that total drug intake as well as the consumption of diuretics and cardiovascular drugs were associated with poorer hydration status, whereas genito-urinary drugs were associated with an opposite effect, and these results were confirmed in terms of body composition. Hence, total drug consumption (β = -0.205), diuretic (β = -0.408), cardiovascular (β = -0.297), and genito-urinary drugs (β = 0.298) were significantly associated (p < 0.05) with total body water. The obtained results confirmed the impact of chronic treatment with certain drugs on hydration status. Nutritional interventions may be of great interest in certain population groups in order to prevent complications due to altered hydration status.

BACKGROUND: Oral fluid intake decreases in advanced cancer in the dying phase of illness. There is inadequate evidence to support the assessment, and management, of hydration in the dying. Bioelectrical impedance analysis (BIA) is a body composition assessment tool. BIA has the potential to inform clinal management in advanced cancer, by examining the relationships between hydration status and clinical variables.
OBJECTIVE: BIA was used to determine the association between hydration status, symptoms, clinical signs, quality-of-life and survival in advanced cancer, including those who are dying (i.e. in the last week of life).
METHODS: We conducted a prospective observational study of people with advanced cancer in three centres. Advance consent methodology was used to conduct hydration assessments in the dying. Total body water was estimated using the BIA Impedance index (Height - H (m)2 /Resistance - R (Ohms)). Backward regression was used to identify factors (physical signs, symptoms, quality of life) that predicted H2/R. Participants in the last 7 days of life were further assessed with BIA to assess hydration changes, and its relationship with clinical outcomes.
RESULTS: One hundred and twenty-five people participated (males n = 74 (59.2%), females, n = 51 (40.8%)). We used backward regression analysis to describe a statistical model to predict hydration status in advanced cancer. The model demonstrated that \'less hydration\' (lower H2/R) was associated with female sex (Beta = -0.39, p < 0.001), increased appetite (Beta = -0.12, p = 0.09), increased dehydration assessment scale score (dry mouth, dry axilla, sunken eyes - Beta = -0.19, p = 0.006), and increased breathlessness (Beta = -0.15, p = 0.03). \'More hydration\' (higher H2/R) was associated with oedema (Beta = 0.49, p < 0.001). In dying participants (n = 18, 14.4%), hydration status (H2/R) was not significantly different compared to their baseline measurements (n = 18, M = 49.6, SD = 16.0 vs. M = 51.0, SD = 12.1; t(17) = 0.64, p = 0.53) and was not significantly associated with agitation (rs = -0.85, p = 0.74), pain (rs = 0.31, p = 0.23) or respiratory tract secretions (rs = -0.34, p = 0.19).
CONCLUSIONS: This is the first study to use bioimpedance to report a model (using clinical factors) to predict hydration status in advanced cancer. Our data demonstrates the feasibility of using an advance consent method to conduct research in dying people. This method can potentially improve the evidence base (and hence, quality of care) for the dying. Future BIA research can involve hydration assessment of cancers (according to type and stage) and associated variables (e.g., stage of illness, ethnicity and gender). Further work can use BIA to identify clinically relevant outcomes for hydration studies and establish a core outcome set to evaluate how hydration affects symptoms and quality-of-life in cancer.

Neurostimulation/neurorecording are tools to study, diagnose, and treat neurological/psychiatric conditions. Both techniques depend on volume conduction between scalp and excitable brain tissue. Here, we examine how neurostimulation with transcranial magnetic stimulation (TMS) is affected by hydration status, a physiological variable that can influence the volume of fluid spaces/cells, excitability, and cellular/global brain functioning. Normal healthy adult participants (32, 9 males) had common motor TMS measures taken in a repeated-measures design from dehydrated (12-h overnight fast/thirst) and rehydrated (identical dehydration protocol followed by rehydration with 1 L water in 1 h) testing days. The target region was left primary motor cortex hand area. Response at the target muscle was recorded with electromyography. Urinalysis confirmed hydration status. Motor hotspot shifted in half of participants. Motor threshold decreased in rehydration, indicating increased excitability. Even after redosing/relocalizing TMS to the new threshold/hotspot, rehydration still showed evidence of increased excitability: recruitment curve measures generally shifted upward and the glutamate-dependent paired-pulse protocol, short intracortical facilitation (SICF), was increased. Short intracortical inhibition (SICI), long intracortical inhibition (LICI), long intracortical facilitation (LICF), and cortical silent period (CSP) were relatively unaffected. The hydration perturbations were mild/subclinical based on the magnitude/speed and urinalysis. Motor TMS measures showed evidence of expected physiological changes of osmotic challenges. Rehydration showed signs of macroscopic and microscopic volume changes including decreased scalp-cortex distance (brain closer to stimulator) and astrocyte swelling-induced glutamate release. Hydration may be a source of variability affecting any techniques dependent on brain volumes/volume conduction. These concepts are important for researchers/clinicians using such techniques or dealing with the wide variety of disease processes involving water balance.NEW & NOTEWORTHY Hydration status can affect brain volumes and excitability, which should affect techniques dependent on electrical volume conduction, including neurostimulation/recording. We test the previously unknown effects of hydration on neurostimulation with TMS and briefly review relevant physiology of hydration. Rehydration showed lower motor threshold, shifted motor hotspot, and generally larger responses even after compensating for threshold/hotspot changes. This is important for clinical and research applications of neurostimulation/neurorecording and the many clinical disorders related to water balance.

BACKGROUND: Hydration plays a critical role in the pathophysiological progression of ischemic stroke. However, the impact of extreme hydration on the mortality of critically ill patients with ischemic stroke remains unclear. Therefore, our objective was to evaluate the association between hydration, as indicated by the blood urea nitrogen to creatinine ratio (UCR), and in-hospital mortality in critically ill patients with ischemic stroke.
METHODS: Data from the Medical Information Mart for Intensive Care (MIMIC-IV) database were utilized. Patients with ischemic stroke admitted to the Intensive Care Unit (ICU) for the first time were identified. The exposure variable was the hydration state represented by the UCR. The study outcome measure was in-hospital mortality. The primary analytical approach involved multivariate Cox regression analysis. Kaplan-Meier curves were constructed, and subgroup analyses with interaction were performed.
RESULTS: A total of 1539 patients, with a mean age of 69.9 years, were included in the study. Kaplan-Meier curves illustrated that patients in higher UCR tertiles exhibited increased in-hospital mortality. Accordingly, the risk of in-hospital mortality significantly rose by 29 % with every 10 units increase in UCR. Subgroup analysis indicated a robust association between UCR and in-hospital mortality in each subgroup, with no statistically significant interactions observed.
CONCLUSIONS: Hydration status is significantly associated with in-hospital all-cause mortality in critically ill patients with ischemic stroke. This finding underscores the importance of closely monitoring critically ill patients for adequate hydration and implementing appropriate rehydration strategies.

BACKGROUND: Adequate hydration is essential for maintaining the health and functionality of the human body. This study aimed to examine the association between selected socioeconomic, lifestyle, and health factors and the hydration status of adults with metabolic disorders by analyzing their urine osmolality.
METHODS: The study involved 290 adults aged 18-70 years with metabolic disorders. Separate multivariate logistic regression models were conducted to evaluate the factors associated with urine osmolality in tertiles for women and men. Odds Ratios (OR) and 95% Confidence Intervals (95% CI) were calculated.
RESULTS: In women, the following factors of urine osmolality were identified in 1st tertile: age (OR:1.04), physical activity (moderate/high vs. no/low; OR:0.38), and headaches (no vs. yes; OR:1.55), in 2nd tertile: physical activity (moderate/high vs. no/low; OR:2.46) and fatigue during the day (sometimes vs. never/very rarely; OR:0.45), and in 3rd tertile: age (OR:0.94), professional status (\'I work part-time/I study and I work\' vs. \'I do not work/I study\'; OR:0.27), fatigue during the day (very often vs. never/very rarely; OR:2.55), and headaches (no vs. yes; OR:0.44). In men, the following factors of urine osmolality were identified in 1st tertile: place of residence (city vs. village; OR:2.72) and health assessment (average vs. poor; OR:0.32).
CONCLUSIONS: Different factors affecting urine osmolality have been identified in women and men. These results highlight the need to implement studies to clarify the relationship between socioeconomic, lifestyle and health factors, and hydration status in adults with metabolic disorders.

UNASSIGNED: The purpose of the review was to evaluate the literature exploring nutritional habits and practices in female soccer players.
UNASSIGNED: The PRISMA-ScR Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews were followed. Searches of Web of Science, PubMed and Scopus databases were conducted for studies exploring the nutritional habits and practices of female soccer players.
UNASSIGNED: A total of 72 studies were included in the scoping review. Studies on female soccer players mainly focused on daily energy expenditure, daily energy and macronutrient intake and hydration status. A negative energy balance was consistent across studies, and the ingestion of CHO appears below the current recommendations. Female soccer players are predominately in negative energy balance, which may indicate that they are at risk of low energy availability. A high use of nutritional supplements is apparent in female soccer, whilst a large proportion of players commence training dehydrated.
UNASSIGNED: The current findings have implications for practitioners relating to the planning, management, monitoring, and implementation of nutritional intake and training and competition schedules.

OBJECTIVE: The National Institute for Health and Care Excellence\'s (NICE) Guideline for Maintenance Fluid Therapy in Adults in Hospital is widely used, but the recommendations have not been evaluated properly. In this study, we investigated whether the recommendation of providing 25-30 mL/kg/day of fluid and 1 mmol/kg each of sodium and potassium is sufficient for human needs.
METHODS: First, we calculated the distribution of fluid between the extracellular fluid volume (ECV) and intracellular fluid volume (ICV) during a cross-over infusion experiment where 12 volunteers received 25 mL/kg/day of either a high-sodium (154 mmol/L) or low-sodium (54 mmol/L) solution over 48 h. Second, urine samples from 719 volunteers and clinical patients were used to quantify their renal water conservation and excretion of sodium and potassium. Third, retrospective analysis of a diet study was used to extrapolate how large the fluid intake and the electrolyte excretion likely had been in the 719 volunteers and hospital patients who delivered urine.
RESULTS: The high-sodium fluid maintained the ECV but the ICV had decreased by 1.3 L after 48 h. The low-sodium fluid resulted in a volume deficit of 1.7 L that equally affected the ECV and the ICV. Regression equations based on the diet study suggested that the daily intake of water in the 719 subjects averaged 2.6 L and that 2 mmol/kg of sodium and 1 mmol/kg of potassium was excreted.
CONCLUSIONS: The NICE guideline recommends too little water and sodium for a human to adequately maintain the ECV and ICV.
BACKGROUND: EudraCT 2016-001846-24 and ISRCTN 12215472.

Dehydration is a well-known problem worldwide, and its assessment can be challenging due to confusing physical signs. The most effective way to assess hydration status is through the costly stable isotope methodology, but this approach has practical limitations. More commonly accepted and utilized indicators of hydration status are hematological and urinary parameters. However, hematological markers require invasive methods, and urinary markers have varying degrees of success in tracking hydration changes. While alterations in body weight can serve as a means of promptly evaluating hydration status, various factors such as food consumption, fluid intake, fecal losses, and urine production can impact these changes. Researchers have turned their attention to saliva as a potential marker and point-of-care (POC) testing to address the limitations of existing biomarkers. Saliva is appealing due to its easy collection process and similarities to extracellular fluid in terms of water and ion concentrations. Recent studies have shown that saliva flow rate, osmolarity/osmolality, and total protein concentration can effectively monitor changes in body mass during acute dehydration. Misdiagnosing dehydration can have severe clinical consequences, leading to morbidity and even mortality. This narrative review focuses on recognizing the significance of hydration assessment, monitoring, and the potential of salivary osmolarity (SOSM) as an assessment tool. Healthcare professionals can improve their practices and interventions to optimize hydration and promote overall wellness using such tools.

Diabetes, especially type 2 diabetes (T2D), poses an unprecedented challenge to global public health. Hydration status also plays a fundamental role in human health, especially in people with T2D, which is often overlooked. This study aimed to explore the longitudinal associations between hydration status and the risk of T2D among the Chinese population. This study used data from the large community-based Kailuan cohort, which included adults who attended physical examinations from 2006 to 2007 and were followed until 2020. A total of 71,526 participants who eventually met the standards were divided into five hydration-status groups based on their levels of urine specific gravity (USG). Multivariable and time-dependent Cox proportional hazards models were employed to evaluate the associations of baseline and time-dependent hydration status with T2D incidence. Restricted cubic splines (RCS) analysis was used to examine the dose-response relationship between hydration status and the risk of T2D. Over a median 12.22-year follow-up time, 11,804 of the participants developed T2D. Compared with the optimal hydration-status group, participants with dehydration and severe dehydration had a significantly increased risk of diabetes, with adjusted hazard ratios (95% CI) of 1.30 (1.04-1.63) and 1.38 (1.10-1.74). Time-dependent analyses further confirmed the adverse effects of impending dehydration, dehydration, and severe dehydration on T2D incidence by 16%, 26%, and 33% compared with the reference group. Inadequate hydration is significantly associated with increased risks of T2D among Chinese adults. Our findings provided new epidemiological evidence and highlighted the potential role of adequate hydration status in the early prevention of T2D development.

OBJECTIVE: Both short and long sleep durations are associated with decreased kidney function; however, few studies have examined the relationship between sleep, hydration status, and plain water intake. This study aimed to assess the relationship between sleep quality, hydration status, and plain water intake in pregnant women.
METHODS: A cross-sectional study method was used to collect data from 380 pregnant women with regular examinations at the hospital between May 2019 and February 2021.
RESULTS: There were statistically significant differences in daily plain water intake (x2 = 14.118, p = 0.001), PSQI score (x2 = 77.708, p < 0.001), sleep duration (x2 = 67.569, p > 0.001), subjective sleep quality (x2 = 67.441, p = 0.001), time to fall asleep (x2 = 64.782, p < 001), sleep disorders (x2 = 70.853, p < 0.001), and daytime dysfunction (x2 = 38.441, p < 0.001) among different hydration status groups. Ordinal logistic regression results indicated that the intake of plain water ≥1500 mL/d (OR = 0.40, 95% CI = 0.24~0.67), good subjective sleep quality (OR = 0.15, 95% CI = 0.07~0.32), short time to fall asleep (OR = 0.32, 95% CI = 0.14~0.70), 8 h of sleep (OR = 0.06, 95% CI = 0.02~0.17), 6-7 h of sleep (OR = 0.19, 95% CI = 0.07~0.54), no sleep disturbance (OR = 0.31, 95% CI = 0.11~0.89), and high sleep efficiency (OR = 0.46, 95% CI = 0.03~0.79) were factors that were correlated with optimal hydration status. Sleep duration and daytime dysfunction partially mediated the effect of plain water intake on hydration status. The mediating effect of sleep duration was -0.036, accounting for 14.006% of the overall effect. The mediating effect of daytime dysfunction was -0.024, accounting for 9.459% of the overall effect.
CONCLUSIONS: The hydration status in pregnant women may be affected by daily plain water intake and sleep quality.