Cardiorenal Syndromes and Their Role in Water and Sodium Homeostasis.

Sodium is the main osmotically active ion in the extracellular fluid and its concentration goes hand in hand with fluid volume. Under physiological conditions, homeostasis of sodium and thus amount of fluid is regulated by neural and humoral interconnection of body tissues and organs. Both heart and kidneys are crucial in maintaining volume status. Proper kidney function is necessary to excrete regulated amount of water and solutes and adequate heart function is inevitable to sustain renal perfusion pressure, oxygen supply etc. As these organs are bidirectionally interconnected, injury of one leads to dysfunction of another. This condition is known as cardiorenal syndrome. It is divided into five subtypes regarding timeframe and pathophysiology of the onset. Hemodynamic effects include congestion, decreased cardiac output, but also production of natriuretic peptides. Renal congestion and hypoperfusion leads to kidney injury and maladaptive activation of renin-angiotensin-aldosterone system and sympathetic nervous system. In cardiorenal syndromes sodium and water excretion is impaired leading to volume overload and far-reaching negative consequences, including higher morbidity and mortality of these patients. Keywords: Cardiorenal syndrome, Renocardiac syndrome, Volume overload, Sodium retention.

Personalized Hydration Strategy to Improve Fluid Balance and Intermittent Exercise Performance in the Heat.

Sweat rate and electrolyte losses have a large inter-individual variability. A personalized approach to hydration can overcome this issue to meet an individual's needs. This study aimed to investigate the effects of a personalized hydration strategy (PHS) on fluid balance and intermittent exercise performance. Twelve participants conducted 11 laboratory visits including a VO2max test and two 5-day trial arms under normothermic (NOR) or hyperthermic (HYP) environmental conditions. Each arm began with three days of familiarization exercise followed by two random exercise trials with either a PHS or a control (CON). Then, participants crossed over to the second arm for: NOR+PHS, NOR+CON, HYP+PHS, or HYP+CON. The PHS was prescribed according to the participants' fluid and sweat sodium losses. CON drank ad libitum of commercially-available electrolyte solution. Exercise trials consisted of two phases: (1) 45 min constant workload; (2) high-intensity intermittent exercise (HIIT) until exhaustion. Fluids were only provided in phase 1. PHS had a significantly greater fluid intake (HYP+PHS: 831.7 ± 166.4 g; NOR+PHS: 734.2 ± 144.9 g) compared to CON (HYP+CON: 369.8 ± 221.7 g; NOR+CON: 272.3 ± 143.0 g), regardless of environmental conditions (p < 0.001). HYP+CON produced the lowest sweat sodium concentration (56.2 ± 9.0 mmol/L) compared to other trials (p < 0.001). HYP+PHS had a slower elevated thirst perception and a longer HIIT (765 ± 452 s) compared to HYP+CON (548 ± 283 s, p = 0.04). Thus, PHS reinforces fluid intake and successfully optimizes hydration status, regardless of environmental conditions. PHS may be or is an important factor in preventing negative physiological consequences during high-intensity exercise in the heat.

Evaluating fluid overload in critically ill children.

PURPOSE OF REVIEW: To review the evaluation and management of fluid overload in critically ill children. RECENT FINDINGS: Emerging evidence associates fluid overload, i.e. having a positive cumulative fluid balance, with adverse outcome in critically ill children. This is most likely the result of impaired organ function due to increased extravascular water content. The combination of a number of parameters, including physical, laboratory and radiographic markers, may aid the clinician in monitoring and quantifying fluid status, but all have important limitations, in particular to discriminate between intra- and extravascular water volume. Current guidelines advocate a restrictive fluid management, initiated early during the disease course, but are hampered by the lack of high quality evidence. SUMMARY: Recent advances in early evaluation of fluid status and (tailored) restrictive fluid management in critically ill children may decrease complications of fluid overload, potentially improving outcome. Further clinical trials are necessary to provide the clinician with solid recommendations.

Fluid balance versus weighing: A comparison in ICU patients: A single center observational study.

BACKGROUND: The fluid balance is a critical parameter in intensive care units (ICU) as it provides information about the patient's volume status. However, the accuracy of fluid balance measurements is often compromised due to the complexity and repetition of actions involved. Additionally, the fluid balance could be recalculated for insensible fluid loss. Weighing is an alternative method to estimate the patient's volume status. Built-in scales in beds make patient weighing easier and less time-consuming, allowing clinicians to intervene more quickly on existing treatments. AIM: This study compares fluid balance, and body weight changes over time in ICU patients. Furthermore, it seeks to determine the degree of congruence between the fluid balance corrected for insensible fluid loss and daily body weight in ICU patients. METHODS: A single-center observational study was conducted in an ICU of a university hospital. All consecutive patients admitted to a bed with an integrated weighing scale were eligible. Exclusion criteria were (1) body weight ≥254,4 kilograms; (2) oral nutrition; (3) a flush catheter or balance; (4) only a single weight measurement; (5) delta body weight change of ≥5kg in 12 hours. Weights and fluid balances were obtained every 12 hours. RESULTS: We obtained 2282 measurements (n = 187 patients). The correlation between weight and fluid balance was weak (r = 0.274). After adjusting the fluid balance for insensible fluid loss, the correlation remained weak (r = 0,268). Bland Altman analysis revealed a wide confidence interval for both the fluid balance and corrected fluid balance versus weight. CONCLUSION AND IMPLICATIONS OF KEY FINDINGS: This study shows a weak correlation between weight and fluid balance. Therefore, when monitoring the volume status in the ICU, fluid balance and weight should both be taken into account. This two-pronged approach is crucial because it provides more control over erroneous fluid balance or weighing measurements.

Inhibition of pannexin-1 does not restore electrolyte balance in precystic Pkd1 knockout mice.

Mutations in PKD1 and PKD2 cause autosomal dominant polycystic kidney disease (ADPKD), which is characterized by the formation of fluid-filled cysts in the kidney. In a subset of ADPKD patients, reduced blood calcium (Ca2+) and magnesium (Mg2+) concentrations are observed. As cystic fluid contains increased ATP concentrations and purinergic signaling reduces electrolyte reabsorption, we hypothesized that inhibiting ATP release could normalize blood Ca2+ and Mg2+ levels in ADPKD. Inducible kidney-specific Pkd1 knockout mice (iKsp-Pkd1-/-) exhibit hypocalcemia and hypomagnesemia in a precystic stage and show increased expression of the ATP-release channel pannexin-1. Therefore, we administered the pannexin-1 inhibitor brilliant blue-FCF (BB-FCF) every other day from Day 3 to 28 post-induction of Pkd1 gene inactivation. On Day 29, both serum Ca2+ and Mg2+ concentrations were reduced in iKsp-Pkd1-/- mice, while urinary Ca2+ and Mg2+ excretion was similar between the genotypes. However, serum and urinary levels of Ca2+ and Mg2+ were unaltered by BB-FCF treatment, regardless of genotype. BB-FCF did significantly decrease gene expression of the ion channels Trpm6 and Trpv5 in both control and iKsp-Pkd1-/- mice. Finally, no renoprotective effects of BB-FCF treatment were observed in iKsp-Pkd1-/- mice. Thus, administration of BB-FCF failed to normalize serum Ca2+ and Mg2+ levels.

Examining the significance of arginine vasopressin release to elucidate the often multifactorial etiology of hypotonic hyponatremia: A novel criterion.

Clinical hyponatremia guidelines, protocols and flowcharts are a convenient means for clinicians to quickly establish an etiological diagnosis for hyponatremia, and facilitate its often complex analysis. Unfortunately, they often erroneously attribute multifactorial hyponatremia to a single cause, which is potentially dangerous. In this manuscript, a novel criterion is proposed to quickly determine the physiological relevance of non-osmotic arginine vasopressin (AVP) release, and to add nuance to hyponatremia analysis. While analyzing hypotonic hyponatremia, it is imperative to not only verify whether or not a certain degree of inappropriate AVP release is present, but also to ascertain whether it-in itself-could sufficiently explain the observed hyponatremia, as these two are not always synonymous. Using well-known concepts from renal physiology to combine the electrolyte-free water balance and solute-free water balance, a novel physiological criterion is derived mathematically to easily distinguish three common hyponatremia scenarios, and to further elucidate the underlying etiology. The derived criterion can hopefully facilitate the clinician's and physiologist's interpretation of plasma and urine parameters in a patient presenting with hyponatremia, and warn against the important clinical pitfall of attributing hyponatremia too readily to a single cause.

Conceptual Approach to Body Fluids and Edema, Education Determines Clinical Outcomes in Heart Failure.

In this brief communication, we reemphasize the importance of critical thinking in clinical practice using the example of edema. The common practice of thinking and inquiry by practicing clinicians has beneficial implications for healthcare by improving outcomes and patient care while alleviating the burden of misconceptions in practice. We provide an in-depth and interactive investigation of physiological concepts as a foundation for understanding body fluid dynamics. Finally, we offer a new classification of symptoms of heart failure. DOI: 10.52547/ijkd.8171.

The tale of an endemic shrimp's exceptional osmoregulation and the ancient Athalassic mangrove oasis.

The hyperarid mangrove in the Middle East is characterised by the absence of rivers or freshwater inputs and is one of the most extreme settings of this ecosystem on Earth. Endemic to Qatar's hyperarid mangroves, a Palaemon shrimp is uniquely confined to a sole mangrove site in the Arabian Gulf. Within these mangrove channels, we unveiled brine groundwater sources exceeding 70 ppt salinity, contrasting the local marine standard of 42 ppt. Concurrently, a mysid species typically linked to salt pans and groundwater coexists. Stable isotopic analysis implied the existence of a predator-prey dynamic between this mysid species and the studied shrimp. Then, investigating the endemic shrimp's adaptation to extreme salinity, we conducted osmolarity experiments and phylogenetic studies. Our findings demonstrate that this shrimp transitions from hypo- to hyper-osmoregulation, tolerating salinities from 18 to 68 ppt-an unprecedented osmoregulatory capacity among caridean shrimps. This speciation pattern likely arises from the species osmolarity adaptation, as suggested for other Palaemon congeners. Phylogenetic analysis of the studied Palaemon, along with the mangrove's geological history, suggests a profound evolutionary interplay between the ecosystem and the shrimp since the Eocene. This study proposes the hyperarid mangrove enclave as an Athalassic mangrove oasis-a distinctive, isolated ecosystem within the desert landscape.

[Establishing a prognostic prediction model for patients with septic shock based on the completion time of fluid resuscitation and the negative fluid balance volumes].

OBJECTIVE: To explore the relationship between the completion time of fluid resuscitation as well as negative fluid balance volumes and the prognosis of patients with septic shock, and to try to construct a prediction model based on the completion time of fluid resuscitation and negative fluid balance volumes, and to verify the predictive efficacy of the model on the prognosis of patients with septic shock. METHODS: Patients with septic shock admitted to Wuxi People's Hospital from April 2020 to April 2023 were selected. The general data (gender, age, body mass index, infection site), pathological indicators on admission, the difference of acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) between admission and 24 hours after fluid resuscitation, the completion time of fluid resuscitation and negative fluid balance volume were recorded. Multivariate Logistic analysis was used to screen the influencing factors of the prognosis of patients with septic shock, and a nomogram model was established. Bootstrap method was used for internal validation of the model. The consistency index, calibration curve and receiver operator characteristic curve (ROC curve) were used to evaluate the accuracy and prediction efficiency of the model. RESULTS: A total of 96 patients with septic shock were enrolled, 38 patients died and 58 patients survived at 28 days. Compared with the survival group, the difference of APACHE II score, SOFA score, the proportion of fluid resuscitation completed within 1 to 3 hours, and the proportion of negative fluid balance volume -500 to -250 mL per day in the death group were lower, and the differences were statistically significant (all P < 0.05). Multivariate Logistic analysis showed that the completion time of fluid resuscitation was a risk factor for the prognosis of patients with septic shock [odds ratio (OR) = 26.285, 95% confidence interval (95%CI) was 9.984-76.902, P < 0.05]. The difference of APACHE II score (OR = 0.045, 95%CI was 0.015-0.131), SOFA score (OR = 0.056, 95%CI was 0.019-0.165) between admission and 24 hours after fluid resuscitation, and negative fluid balance volume (OR = 0.043, 95%CI was 0.015-0.127) were protective factors for the prognosis of patients with septic shock (all P < 0.05). The model validation results showed that the consistency index was 0.681 (95%CI was 0.596-0.924), indicating good discrimination. The calibration curve showed that the calibration curve fitted well with the ideal curve. The ROC curve showed that the sensitivity of the nomogram model for predicting the death of patients with septic shock was 83.7%, the specificity was 97.2%, and the area under the ROC curve (AUC) was 0.931 (95%CI was 0.846-0.985), indicating that the model had good prediction efficiency. CONCLUSIONS: The completion time of fluid resuscitation and negative fluid balance volumes are related to the prognosis of septic shock patients, and the alignment diagram model improve the identification of the risk of death in septic shock patients.

Analysis of Fluid Balance and Urine Values in Elite Soccer Players: Impact of Different Environments, Playing Positions, Sexes, and Competitive Levels.

Exercise can disrupt the fluid balance, hindering performance and athlete health. Limited data exist on fluid balance responses in varying climates, sexes, and ages. This study aimed to measure and compare fluid balance and urine values among elite soccer players during training at high and low temperatures, examining the differences between sexes, playing positions, and competitive levels within men's soccer. During the 2022-2023 competitive season, a descriptive observational study was conducted on 87 soccer players from an elite Spanish soccer team. The study found that none of the groups exceeded weight loss values of 1.5% of their body mass. Additionally, the soccer players studied experienced higher weight loss, fluid intake, and a higher sweat rate (SR) during summer training compared to winter training. During the summer, male U23-21 soccer players exhibited higher levels of weight loss, fluid intake, and a higher SR compared to female soccer players or the U19-17 male category. No significant differences were found between playing positions. In conclusion, differences in the fluid balance were observed based on the climatic conditions, competitive level, and sex.

[Clinical significance of negative fluid balance and infection management in the treatment of acute respiratory distress syndrome caused by severe novel coronavirus infection].

OBJECTIVE: To explore the clinical significance of negative fluid balance and infection management in the treatment of acute respiratory distress syndrome (ARDS) caused by severe novel coronavirus infection. METHODS: A retrospective survey was conducted. Patients with ARDS caused by severe novel coronavirus infection who were hospitalized in the department of critical care medicine of the Third Affiliated Hospital of Gansu University of Chinese Medicine and received non-invasive ventilator assisted ventilation were selected as the research objects. The fluid intake and output of all patients were accurately counted every day, and the fluid intake of the next day was adjusted according to the output of the previous day. According to the fluid negative balance, and whether the hospital infection management measures were complied with during the treatment and inspection of the patients, 45 patients with a negative fluid balance of more than 200 mL/d and strict management of nosocomial infection were taken as the observation group, and 48 patients with a negative fluid balance of less than 200 mL/d and no strict management of nosocomial infection were taken as the control group. The general data, weaning success rate, endotracheal intubation rate, mortality, as well as laboratory indicators such as white blood cell count (WBC), procalcitonin (PCT), C-reactive protein (CRP) after treatment were compared between the two groups. RESULTS: There were no significant differences in gender (male: 51.1% vs. 52.1%), age (years old: 66.31±15.92 vs. 67.50±13.59), acute physiology and chronic health evaluation II (APACHE II: 18.98±4.81 vs. 18.54±4.35) between the observation group and the control group (all P > 0.05), indicating that the baseline data were balanced and comparable. Compared with the control group, the weaning success rate of the observation group significantly increased [53.3% (24/45) vs. 31.2% (15/48), P = 0.031], endotracheal intubation rate significantly decreased [22.2% (10/45) vs. 43.8% (21/48), P = 0.028], mortality significantly reduced [20.0% (9/45) vs. 41.7% (20/48), P = 0.024], laboratory indicators WBC, PCT and CRP levels were significantly reduced [WBC (×109/L): 8.085±4.136 vs. 16.898±7.733, CRP (mg/L): 82.827±52.680 vs. 150.679±74.625, PCT (µg/L): 3.142±2.323 vs. 7.539±5.939, all P < 0.01]. CONCLUSIONS: Fluid negative balance and infection management have significant clinical significance in the treatment of severe novel coronavirus infection with ARDS.

Fluid Management in Acute Respiratory Failure.

Fluid management in acute respiratory failure is an area of uncertainty requiring a delicate balance of resuscitation and fluid removal to manage hypoperfusion and avoidance of hypoxemia. Overall, a restrictive fluid strategy (minimizing fluid administration) and careful attention to overall fluid balance may be beneficial after initial resuscitation and does not have major side effects. Further studies are needed to improve our understanding of patients who will benefit from a restrictive or liberal fluid management strategy.

Assessment of the components of fluid balance in patients with septic shock: a prospective observational study.

BACKGROUND: The optimal amount for initial fluid resuscitation is still controversial in sepsis and the contribution of non-resuscitation fluids in fluid balance is unclear. We aimed to investigate the main components of fluid intake and fluid balance in both survivors and non-survivor patients with septic shock within the first 72 hours. METHODS: In this prospective observational study in two intensive care units, we recorded all fluids administered intravenously, orally, or enterally, and losses during specific time intervals from vasopressor initiation: T1 (up to 24 hours), T2 (24 to 48 hours) and T3 (48 to 72 hours). Logistic regression and a mathematical model assessed the association with mortality and the influence of severity of illness. RESULTS: We included 139 patients. The main components of fluid intake varied across different time intervals, with resuscitation and non-resuscitation fluids such as antimicrobials and maintenance fluids being significant contributors in T1 and nutritional therapy in T2/T3. A positive fluid balance both in T1 and T2 was associated with mortality (p = 0.049; p = 0.003), while nutritional support in T2 was associated with lower mortality (p = 0.040). The association with mortality was not explained by severity of illness scores. CONCLUSIONS: Non-resuscitation fluids are major contributors to a positive fluid balance within the first 48 hours of resuscitation. A positive fluid balance in the first 24 and 48 hours seems to independently increase the risk of death, while higher amount of nutrition seems protective. This data might inform fluid stewardship strategies aiming to improve outcomes and minimize complications in sepsis.

Effects of different salinity reduction intervals on osmoregulation, anti-oxidation and apoptosis of Eriocheir sinensis megalopa.

Eriocheir sinensis megalopa has a special life history of migrating from seawater to freshwater. In order to investigate how the megalopa adapt themselves to the freshwater environment, we designed an experiment to reduce the salinity of water from 30 ppt to 0 at rates of 30 ppt, 15 ppt, 10 ppt, and 5 ppt per 24 h to evaluate the effects of different degrees of hyposaline stress on the osmotic regulation ability and antioxidant system of the megalopa. Experimental results related to osmotic pressure regulation show that the gill tissue of megalopa in the treatment group of 30 ppt/24 h rapid reduction of salinity was damaged, while in the treatment group of 5 ppt/24 h it was intact. At the same time, the experiment also found that in each treatment group with different salinity reduction rates, compared with the control salinity, the NKA activity of megalopa increased significantly after the salinity was reduced to 20 ppt (p < 0.05). In addition, two genes involved in chloride ion transmembrane absorption have different expression patterns in the treatment groups with different salinity reduction rates. Among them, Clcn2 was significantly highly expressed only in the rapid salinity reduction intervals of 30 ppt/24 h and 15 ppt/24 h (p < 0.05). Slc26a6 was significantly highly expressed only in the slow salinity reduction intervals of 10 ppt/24 h and 5 ppt/24 h (p < 0.05). On the other hand, the results of antioxidant and apoptosis related experiments showed that in all treatment groups with different rates of salinity reduction, the activities of T-AOC, GSH-PX, and CAT basically increased significantly after salinity reduction compared to the control salinity. Moreover, the activities of T-AOC and CAT were significantly higher in the 10 ppt/24 h and 5 ppt/24 h treatment groups than in the 30 ppt/24 h and 15 ppt/24 h treatment groups. Finally, the experimental results related to apoptosis showed that the expression trends of Capase3 and Bax-2 were basically the same in the treatment groups with different salinity reduction rates, and their expressions were significantly higher in the 10 ppt/24 h and 5 ppt/24 h treatment groups than in the 30 ppt/24 h and 15 ppt/24 h treatment groups. In summary, the present study found that megalopa had strong hyposaline tolerance and were able to regulate osmolality at different rates of salinity reduction, but the antioxidant capacity differed significantly between treatment groups, with rapid salinity reduction leading to oxidative damage in the anterior gills and reduced antioxidant enzyme activity and apoptosis levels.

A Murine Model for Measuring Sebum Production That Can Be Used to Test Therapeutic Agents for the Management of Acne Vulgaris.

Acne vulgaris (acne) effects nearly 90% of all Western teenagers, and the only pharmaceutical class of agents to treat severe forms of this skin condition are the retinoids, which are well-described teratogens. Yet about 50% of the patients receiving this class of therapeutics are women of child-bearing age, in their peak years of reproductive potential. On this basis, there is a significant unmet medical need for agents to treat severe forms of acne that do not carry this liability. As a means to assess potential agents of this type, here we describe methods for estimating the relative amount of sebum that a mouse produces based on the water retention on fur following a thorough wetting procedure. We have shown that a compound that is clinically effective in reducing sebum production demonstrates activity in this model. The method is therefore useful for evaluating therapeutic candidates for reducing sebum production, which would in turn be useful for treating acne. We have broken the entire procedure down into two phases/two protocols, as listed below. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Pre-wash wet weight measurement Basic Protocol 2: Post-wash wet-weight measurement.

Refeeding syndrome and psychopharmacological interventions in children and adolescents with Anorexia Nervosa: a focus on olanzapine-related modifications of electrolyte balance.

This study aims to investigate the potential correlation between the use of olanzapine, a psychopharmacological intervention commonly prescribed in Anorexia Nervosa treatment, and the occurrence of Refeeding Syndrome. Despite the acknowledged nutritional and biochemical impacts of olanzapine, the literature lacks information regarding its specific association with Refeeding Syndrome onset in individuals with Anorexia Nervosa. This is a naturalistic, retrospective, observational study, reporting the occurrence of Refeeding Syndrome in children and adolescents with Anorexia Nervosa, treated or untreated with olanzapine. Dosages and serum levels of olanzapine were assessed for potential associations with the occurrence of Refeeding Syndrome and specific variations in Refeeding Syndrome-related electrolytes. Overall, 113 patients were enrolled, including 46 (41%) who developed a Refeeding Syndrome. Mild (87%), moderate (6.5%), and severe (6.5%) Refeeding Syndrome was described, at a current average intake of 1378 ± 289 kcal/day (39 ± 7.7 kcal/kg/die), frequently associated with nasogastric tube (39%) or parenteral (2.2%) nutrition. Individuals receiving olanzapine experienced a more positive phosphorus balance than those who did not (F(1,110) = 4.835, p = 0.030), but no difference in the occurrence of Refeeding Syndrome was documented. The mean prescribed doses and serum concentrations of olanzapine were comparable between Refeeding Syndrome and no-Refeeding Syndrome patients.    Conclusion: The present paper describes the occurrence of Refeeding Syndrome and its association with olanzapine prescriptions in children and adolescents with Anorexia Nervosa. Olanzapine was associated with a more positive phosphorus balance, but not with a different occurrence of Refeeding Syndrome. Further, longitudinal studies are required. What is Known: • Refeeding Syndrome (RS) is a critical complication during refeeding in malnourished patients, marked by electrolyte (phosphorus, magnesium, potassium) imbalances. • Olanzapine, an atypical antipsychotic with nutritional and biochemical impacts, is used in Anorexia Nervosa (AN) treatment, however data concerning its association with RS are lacking. What is New: • The study observed RS in 46/113 (41%) young patients with AN. • Olanzapine-treated individuals showed a higher improvement in serum phosphate levels than untreated ones, although no impact on the occurrence of Refeeding Syndrome was observed.

Navigating the multifaceted intricacies of the Na+-Cl- cotransporter, a highly regulated key effector in the control of hydromineral homeostasis.

The Na+-Cl- cotransporter (NCC; SLC12A3) is a highly regulated integral membrane protein that is known to exist as three splice variants in primates. Its primary role in the kidney is to mediate the cosymport of Na+ and Cl- across the apical membrane of the distal convoluted tubule. Through this role and the involvement of other ion transport systems, NCC allows the systemic circulation to reclaim a fraction of the ultrafiltered Na+, K+, Cl-, and Mg+ loads in exchange for Ca2+ and [Formula: see text]. The physiological relevance of the Na+-Cl- cotransport mechanism in humans is illustrated by several abnormalities that result from NCC inactivation through the administration of thiazides or in the setting of hereditary disorders. The purpose of the present review is to discuss the molecular mechanisms and overall roles of Na+-Cl- cotransport as the main topics of interest. On reading the narrative proposed, one will realize that the knowledge gained in regard to these themes will continue to progress unrelentingly no matter how refined it has now become.

Effects of ingesting beverages containing glycerol and sodium with isomaltulose or sucrose on fluid retention in young adults: a single-blind, randomized crossover trial.

We evaluated changes in hyperhydration and beverage hydration index (BHI, a composite measure of fluid balance after consuming a test beverage relative to water) during resting, induced by the consumption of beverages containing glycerol and sodium supplemented with fast-absorbing sucrose or slow-absorbing isomaltulose. In a randomized crossover, single-blinded protocol (clinical trials registry: UMIN000042644), 14 young physically active adults (three women) consumed 1 L of beverage containing either 7% glycerol + 0.5% sodium (Gly + Na), Gly + Na plus 7% sucrose (Gly + Na + Suc), Gly + Na plus 7% isomaltulose (Gly + Na + Iso), or water (CON) over a 40 min period. We assessed the change in plasma volume (ΔPV), BHI (calculated from cumulative urine output following consumption of water relative to that of the beverage), and blood glucose and sodium for 180 min after initiating ingestion. Total urine volume was reduced in all beverages containing glycerol and sodium compared to CON (all P ≤ 0.002). The addition of isomaltulose increased BHI by ∼45% (3.43 ± 1.0 vs. 2.50 ± 0.7 for Gly + Na, P = 0.011) whereas sucrose did not (2.6 ± 0.6, P = 0.826). The PV expansion was earliest for Gly + Na (30 min), slower for Gly + Na + Suc (90 min), and slowest for Gly + Na + Iso (120 min) with a concomitant lag in the increase of blood glucose and sodium concentrations. Supplementation of beverages containing glycerol and sodium with isomaltulose but not sucrose enhances BHI from those of glycerol and sodium only under a resting state, likely due to the slow absorption of isomaltulose-derived monosaccharides (i.e., glucose and fructose).

H2OAthletes study protocol: effects of hydration changes on neuromuscular function in athletes.

We aim to understand the effects of hydration changes on athletes' neuromuscular performance, on body water compartments, fat-free mass hydration and hydration biomarkers and to test the effects of the intervention on the response of acute dehydration in the hydration indexes. The H2OAthletes study (clinicaltrials.gov ID: NCT05380089) is a randomised controlled trial in thirty-eight national/international athletes of both sexes with low total water intake (WI) (i.e. < 35·0 ml/kg/d). In the intervention, participants will be randomly assigned to the control (CG, n 19) or experimental group (EG, n 19). During the 4-day intervention, WI will be maintained in the CG and increased in the EG (i.e. > 45·0 ml/kg/d). Exercise-induced dehydration protocols with thermal stress will be performed before and after the intervention. Neuromuscular performance (knee extension/flexion with electromyography and handgrip), hydration indexes (serum, urine and saliva osmolality), body water compartments and water flux (dilution techniques, body composition (four-compartment model) and biochemical parameters (vasopressin and Na) will be evaluated. This trial will provide novel evidence about the effects of hydration changes on neuromuscular function and hydration status in athletes with low WI, providing useful information for athletes and sports-related professionals aiming to improve athletic performance.

[Features of water-electrolyte balance in persons of the older age group].

Age-related changes have a great influence on the regulation of water and electrolyte homeostasis in the body, which is regulated by a complex interaction of environmental factors, drinking behavior, the secretion of a number of hormones and hormone-like substances, as well as the innervation and functional state of the kidneys. It is well known that the changes that are part of physiological aging underlie fluid and electrolyte imbalances, exacerbated by the presence of age-related diseases, medications, or a number of external factors such as malnutrition, fluid intake, and the presence of dementia. This review considers literature data on the effect of normal aging on the development of pathology of the water-sodium balance, including dehydration of senile patients, hyponatremia, hypernatremia, changes in the secretion of antidiuretic hormone and the activity of elements of the renin-angiotensin-aldosterone system.