The characteristics of eating, drinking and oro-pharyngeal swallowing difficulties associated with repaired oesophageal atresia/tracheo-oesophageal fistula: a systematic review and meta-proportional analysis.

INTRODUCTION: Eating, drinking and swallowing difficulties are commonly reported morbidities for individuals born with OA/TOF. This study aimed to determine the nature and prevalence of eating, drinking and oro-pharyngeal swallowing difficulties reported in this population. METHOD: A systematic review and meta-proportional analysis were conducted (PROSPERO: CRD42020207263). MEDLINE, EMBASE, CINAHL, Pubmed, Scopus, Web of Science databases and grey literature were searched. Quantitative and qualitative data were extracted relating to swallow impairment, use of mealtime adaptations and eating and drinking-related quality of life. Quantitative data were summarised using narrative and meta-proportional analysis methods. Qualitative data were synthesised using a meta-aggregation approach. Where quantitative and qualitative data described the same phenomenon, a convergent segregated approach was used to synthesise data. RESULTS: Sixty-five studies were included. Six oro-pharyngeal swallow characteristics were identified, and pooled prevalence calculated: aspiration (24%), laryngeal penetration (6%), oral stage dysfunction (11%), pharyngeal residue (13%), nasal regurgitation (7%), delayed swallow initiation (31%). Four patient-reported eating/drinking difficulties were identified, and pooled prevalence calculated: difficulty swallowing solids (45%), difficulty swallowing liquids (6%), odynophagia (30%), coughing when eating (38%). Three patient-reported mealtime adaptations were identified, and pooled prevalence calculated: need for water when eating (49%), eating slowly (37%), modifying textures (28%). Mixed methods synthesis of psychosocial impacts identified 34% of parents experienced mealtime anxiety and 25% report challenging mealtime behaviours reflected in five qualitative themes: fear and trauma associated with eating and drinking, isolation and a lack of support, being aware and grateful, support to cope and loss. CONCLUSIONS: Eating and drinking difficulties are common in adults and children with repaired OA/TOF. Oro-pharyngeal swallowing difficulties may be more prevalent than previously reported. Eating, drinking and swallowing difficulties can impact on psychological well-being and quality of life, for the individual and parents/family members. Long-term, multi-disciplinary follow-up is warranted.

OCT angiographic evaluation of changes in macula and optic nerve head vessel density after a water drinking test in glaucomatous and healthy eyes.

PURPOSE: To evaluate the effects of a water drinking test (WDT) on the intraocular pressure (IOP) and vascular density of the optic nerve head and macula in healthy individuals and those with primary open glaucoma using optical coherence tomography angiography. METHODS: In this prospective comparative study, 30 healthy patients and 44 POAG subjects were divided into two groups. The study's outcome measures were the IOP and vessel density of the optic nerve and macular area. After ingesting 1000 ml of water in 5 min, the effect of the WDT on the IOP and the vascular density of the macular area and optic nerve head were measured at baseline and then 20, 40, and 60 min later at intervals of 20 min. RESULTS: The initial IOP in the healthy and glaucomatous eye groups was comparable (15.94 ± 2.6 and 16.87 ± 4.21 mmHg, respectively, P = 0.506). The IOP of both groups peaked at 40' measurements. POAG eyes had significantly higher IOP elevation (4.34 ± 0.30 vs. 2.24 ± 0.30 mmHg, P < 0.001). The glaucomatous eyes had lower radial peripapillary capillary (RPC) and whole macular superficial capillary plexus (SCP) densities at baseline (48.55 ± 5.99 vs. 51.33 ± 3.75) and (48.92 ± 3.41 vs. 45.29 ± 5.29), respectively (P < 0.001). After the WDT, the change in vessel density between groups in the RPC, whole superficial, and deep capillary plexuses was insignificant (SCP and DCP of 0.66 and 0.70, respectively, P = 0.16). CONCLUSION: The WDT caused a significant IOP jump in both glaucomatous and healthy eyes, but generally, the alterations in the glaucomatous eyes were more pronounced. The changes in vascular density in the macula and optic nerve head were similar between the groups.

Investigating Water Balance as a Nutritional Determinant in Breastfeeding: A Comparative Study of Water Consumption Patterns and Influencing Factors.

BACKGROUND: Ensuring adequate hydration is critical for breastfeeding women, yet their water consumption patterns and hydration status is poorly understood. This study investigates the water consumption patterns and estimated water balance among women, practicing exclusive, mixed, and no breastfeeding methods. METHODS: 529 healthy women completed the Nursing Water Balanced Questionnaire (N-WBQ). Participants were distributed across breastfeeding groups as follows: exclusive (39.7%), mixed (31.9%), and no breastfeeding (28.4%). RESULTS: Significant differences were noted in water consumption patterns among breastfeeding groups regarding intake from beverages (p < 0.001), juices (p = 0.019), coffee (p < 0.001), and milk (p = 0.015). Water intake from liquids, except for drinking water (p < 0.001), juices (p = 0.024) and coffee (p < 0.001) differed significantly among groups in women with adequate total water intake based on recommendation, with exclusive breastfeeding mothers prioritizing plain water over other beverages. Total water loss (p < 0.001) and estimated water balance (p < 0.001) significantly varied among breastfeeding groups, with exclusive breastfeeding mothers to exhibit the lowest water balance (-475.36 mL/day), indicating potential dehydration risk. Apart from plain water, water from foods, coffee and milk significantly contributed to positive water balance. CONCLUSIONS: Our findings highlight a risk of dehydration in this population, while water consumption patterns are influenced by breastfeeding method, likely affected by varying lactational demands and lifestyle factors. Further research to develop more accurate and individualized methods for assessing water balance in breastfeeding women is needed.

Association of Knowledge and Health Habits with Physiological Hydration Status.

The association of hydration knowledge and health habits with hydration status and fluid intake is rarely examined. We sought to determine whether knowledge or physical health behaviors predict physiological hydration status and fluid intake. Ninety-six participants (59 female; 27 ± 10 year) completed the previously validated hydration survey. Participants then recorded total fluids consumed (TFC), collected urine, and tracked void frequency for 24 h. Hydration status was assessed via 24 h urine specific gravity (USG) and osmolality (Uosm). Health behaviors included self-reported physical activity, BMI, smoking, alcoholic drinking, and sleep status. TFC was significantly correlated with 24 h USG (r = -0.390; p < 0.001), Uosm (r = -0.486; p < 0.001), total urine volume (r = 0.675; p < 0.001), and void frequency (r = 0.518; p < 0.001). Hydration knowledge was not correlated with 24 h USG (r = 0.085; p = 0.420), Uosm (r = 0.087; p = 0.419), urine total volume (r = 0.019; p = 0.857), void frequency (r = 0.030; p = 0.771), or TFC (r = 0.027; p = 0.813). Hydration knowledge did not predict 24 h USG (LR+ = 1.10; LR- = 0.90), Uosm (LR+ = 0.81; LR- = 1.35), or TFC (LR+ = 1.00; LR- = 1.00). Health habits did not predict 24 h USG, Uosm, or TFC. In conclusion, self-reported 24 h diet and fluid log recording is comparable to hydration status verification via 24 h urine collection. Hydration knowledge and health habits are not related to, or predictive of, hydration status.

Seasonality Affects Fluid Intake Behaviors among Young Adults in Hebei, China.

BACKGROUND: Evidence on the association between environmental factors and fluid intake behavior remains limited. The current study aims to explore seasonal variations in fluid intake behaviors among young adults in China. METHODS: A prospective cohort of 79 healthy young adults (43 males and 36 females) aged 19-21 in Hebei, China, was assessed for fluid intake behaviors for four seasons. For each assessment, the participants' anthropometric measurements were collected. Temperature and humidity on survey days were measured. Participants' total drinking fluid (TDF) was recorded using a self-administrative 7 d, 24 h fluid intake questionnaire. To calculate water from food (WFF), we weighed all foods consumed by participants. Duplicates of consumed food samples were collected to measure the water content via the drying method. RESULTS: The mean total water intake (TWI) was 2761 ± 881, 2551 ± 845, 2210 ± 551, and 1989 ± 579 for spring, summer, fall, and winter, respectively (F(2.37) = 42.29, p < 0.001). The volume and proportion of TWI from TDF and WFF varied across the four seasons. The volume of WFF in spring (1361 ± 281, F(2.61) = 17.21, p < 0.001) and TDF in summer (1218 ± 502, F(2.62) = 9.36, p < 0.001) was among the highest, while participants' fluid intake behaviors in spring and summer were less distinct than the other pairwise comparisons. A moderate association was found between outdoor temperature and TDF (r = 0.53, p < 0.01). Different general estimating equations suggested that gender, seasonality, outdoor temperature, differences in indoor and outdoor temperature, and mean temperature were independent factors of TDF. An interactive effect was found for gender and temperature, showing that the expected TDF of males may increase more as the temperature climbs. CONCLUSIONS: Gender, seasonality, and air temperature could significantly affect fluid intake behaviors, including the amount and type of fluid intake. However, the independent effect of BMI and humidity remains unclear.

Plain Water Intake, Sleep Quality, and Hydration Status of Pregnant Woman in Hainan, China: A Cross-Sectional Study.

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. CONCLUSION: The hydration status in pregnant women may be affected by daily plain water intake and sleep quality.

Peri-ictal Water Drinking in an Omani Patient with Bilateral Mesial Temporal Sclerosis.

Peri-ictal water drinking (PIWD) is a rare vegetative manifestation of temporal lobe epilepsy without a definite lateralisation value. We report a case of PIWD in a 22-year-old Omani male patient with post-concussion syndrome and epilepsy presented to a tertiary care hospital in Muscat, Oman, in 2021 for evaluation of paroxysmal events. His behaviour of PIWD was misinterpreted by his family until characterised in the epilepsy-monitoring unit as a manifestation of epilepsy that was treated medically. To the best of the authors' knowledge, this is the second reported case in the region.

Fluid transitions.

Water is critical for survival and thirst is a powerful way of ensuring that fluid levels remain in balance. Overconsumption, however, can have deleterious effects, therefore optimization requires a need to balance the drive for water with the satiation of that water drive. This review will highlight our current understanding of how thirst is both generated and quenched, with particular focus on the roles of angiotensin II, glucagon like-peptide 1, and estradiol in turning on and off the thirst drive. Our understanding of the roles these bioregulators play has benefited from modern behavioral analyses, which have improved the time resolution of intake measures, allowing for attention to the details of the patterns within a bout of intake. This has led to behavioral interpretation in ways that are helpful in understanding the many controls of water intake and has expanded our understanding beyond the dichotomy that something which increases water intake is simply a "stimulator" while something that decreases water intake is simply a "satiety" factor. Synthesizing the available information, we describe a framework in which thirst is driven directly by perturbations in fluid intake and indirectly modified by several bioregulators. This allows us to better highlight areas that are in need of additional attention to form a more comprehensive understanding of how the system transitions between states of thirst and satiety.

Trends and Missing Links in (De)Hydration Research: A Narrative Review.

Despite decades of literature on (de)hydration in healthy individuals, many unanswered questions remain. To outline research and policy priorities, it is fundamental to recognize the literature trends on (de)hydration and identify current research gaps, which herein we aimed to pinpoint. From a representative sample of 180 (de)hydration studies with 4350 individuals, we found that research is mainly limited to small-scale laboratory-based sample sizes, with high variability in demographics (sex, age, and level of competition); to non-ecological (highly simulated and controlled) conditions; and with a focus on recreationally active male adults (e.g., Tier 1, non-athletes). The laboratory-simulated environments are limiting factors underpinning the need to better translate scientific research into field studies. Although, consistently, dehydration is defined as the loss of 2% of body weight, the hydration status is estimated using a very heterogeneous range of parameters. Water is the most researched hydration fluid, followed by alcoholic beverages with added carbohydrates (CHO). The current research still overlooks beverages supplemented with proteins, amino acids (AA), and glycerol. Future research should invest more effort in "real-world" studies with larger and more heterogeneous cohorts, exploring the entire available spectrum of fluids while addressing hydration outcomes more harmoniously.

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.

Differences in urine creatinine and osmolality between black and white Americans after accounting for age, moisture intake, urine volume, and socioeconomic status.

Urine osmolality is used throughout research to determine hydration levels. Prior studies have found black individuals to have elevated urine creatinine and osmolality, but it remains unclear which factors explain these findings. This cross-sectional, observational study sought to understand the relationship of self-reported race to urine creatinine and urine osmolality after accounting for age, socioeconomic status, and fluid intake. Data from 1,386 participants of the 2009-2012 National Health and Nutrition Examination Survey were utilized. Age, poverty-to-income ratio (PIR), urine flow rate (UFR), fluid intake, estimated lean body mass (LBM), urine creatinine, and urine osmolality were measured. In a sex-specific manner, black and white participants were matched on age, dietary moisture, UFR, and PIR. Urine creatinine was greater in black men (171 mg/dL) than white men (150 mg/dL) and greater in black women (147 mg/dL) than white women (108 mg/dL) (p < .001). Similarly, urine osmolality was greater in black women than white women (723 vs. 656 mOsm/kg, p = .001), but no difference was observed between white and black men (737 vs. 731 mOsm/kg, p = .417). Estimated LBM was greater in black men (61.8 kg) and women (45.5 kg) than in white men (58.9 kg) and women (42.2 kg) (p≤.001). The strongest correlate of urine osmolality in all race-sex groups was urine creatinine (Spearman ρ = .68-.75). These results affirm that individuals identifying as black produce higher urine creatinine concentrations and, in women, higher urine osmolality after matching for age, fluid intake, and socioeconomic status. The findings suggest caution when comparing urine hydration markers between racial groups.

Stimulus-Response Plots as a Novel Bowel-Sound-Based Method for Evaluating Motor Response to Drinking in Healthy People.

Constipation is a common gastrointestinal disorder that impairs quality of life. Evaluating bowel motility via traditional methods, such as MRI and radiography, is expensive and inconvenient. Bowel sound (BS) analysis has been proposed as an alternative, with BS-time-domain acoustic features (BSTDAFs) being effective for evaluating bowel motility via several food and drink consumption tests. However, the effect of BSTDAFs before drink consumption on those after drink consumption is yet to be investigated. This study used BS-based stimulus-response plots (BSSRPs) to investigate this effect on 20 participants who underwent drinking tests. A strong negative correlation was observed between the number of BSs per minute before carbonated water consumption and the ratio of that before and after carbonated water consumption. However, a similar trend was not observed when the participants drank cold water. These findings suggest that when carbonated water is drunk, bowel motility before ingestion affects motor response to ingestion. This study provides a non-invasive BS-based approach for evaluating motor response to food and drink, offering a new research window for investigators in this field.

Does Meal or Water Intake Affect Ultrasound Attenuation Coefficient Estimate?

OBJECTIVES: To assess whether meal or water intake may affect the measurement of the ultrasound (US) attenuation coefficient (AC) imaging, a parameter that is directly related to liver fat content. METHODS: The study was performed in two centers (Italy and USA). AC was obtained using the ATI algorithm implemented in the Aplio i-series US systems (Canon Medical Systems, Japan) by one operator at each center. Measurements were performed at baseline and 5, 15, 30, 45 minutes after drinking 500 mL of water (group 1), or 30, 45, 60, 90, 120 minutes after eating a meal of about 600 kcal (group 2). Multilevel generalized estimating equations for repeated measures were used for the statistical analysis to consider the clustered nature of the data. RESULTS: Twenty-six individuals were enrolled: 11 (10 females; age, 43.7 ± 12.5 years) in Italy and 15 (10 females; age, 60.7 ± 6.3 years) in USA. At B-mode US, 10 (38.5%) had liver steatosis. The baseline AC values, in decibel/centimeter/megahertz, were 0.64 (0.12) in group 1 and 0.66 (0.13) in group 2. There was not any significant difference in AC values at every time-point after water or meal intake either in group 1 or group 2. This result did not change including sex, age, and skin-to-liver capsule into the models. CONCLUSIONS: The measurement of the AC, which is a biomarker of liver steatosis, does not require a fasting state and drinking water does not affect the result.

Dietary sodium and fluid intake in heart failure. A clinical consensus statement of the Heart Failure Association of the ESC.

Sodium and fluid restriction has traditionally been advocated in patients with heart failure (HF) due to their sodium and water avid state. However, most evidence regarding the altered sodium handling, fluid homeostasis and congestion-related signs and symptoms in patients with HF originates from untreated patient cohorts and physiological investigations. Recent data challenge the beneficial role of dietary sodium and fluid restriction in HF. Consequently, the European Society of Cardiology HF guidelines have gradually downgraded these recommendations over time, now advising for the limitation of salt intake to no more than 5 g/day in patients with HF, while contemplating fluid restriction of 1.5-2 L/day only in selected patients. Therefore, the objective of this clinical consensus statement is to provide advice on fluid and sodium intake in patients with acute and chronic HF, based on contemporary evidence and expert opinion.

Cannabinoids regulate an insula circuit controlling water intake.

The insular cortex, or insula, is a large brain region involved in the detection of thirst and the regulation of water intake. However, our understanding of the topographical, circuit, and molecular mechanisms for controlling water intake within the insula remains parcellated. We found that type-1 cannabinoid (CB1) receptors in the insular cortex cells participate in the regulation of water intake and deconstructed the circuit mechanisms of this control. Topographically, we revealed that the activity of excitatory neurons in both the anterior insula (aIC) and posterior insula (pIC) increases in response to water intake, yet only the specific removal of CB1 receptors in the pIC decreases water intake. Interestingly, we found that CB1 receptors are highly expressed in insula projections to the basolateral amygdala (BLA), while undetectable in the neighboring central part of the amygdala. Thus, we recorded the neurons of the aIC or pIC targeting the BLA (aIC-BLA and pIC-BLA) and found that they decreased their activity upon water drinking. Additionally, chemogenetic activation of pIC-BLA projection neurons decreased water intake. Finally, we uncovered CB1-dependent short-term synaptic plasticity (depolarization-induced suppression of excitation [DSE]) selectively in pIC-BLA, compared with aIC-BLA synapses. Altogether, our results support a model where CB1 receptor signaling promotes water intake by inhibiting the pIC-BLA pathway, thereby contributing to the fine top-down control of thirst responses.

Comparison of intraocular pressure profiles during the water drinking test and the modified diurnal tension curve.

OBJECTIVES: To compare intraocular pressure (IOP) during the water drinking test (WDT) and modified diurnal tension curve (mDTC) in open-angle glaucoma (OAG) patients, using multimodal, observer-masked tonometry. METHODS: Open-angle glaucoma subjects were prospectively enroled, excluding those who had undergone glaucoma filtration or laser surgery. Two-hourly mDTC Goldmann applanation (GAT) and rebound tonometry (RT) was performed between 8:00 and 16:00, and every 15 min for 45 min after ingestion of 800mls of water. Blood pressure, heart rate, pupillometry measurements, and optical coherence tomography (AS-OCT) were also recorded. RESULTS: Forty-two subjects' right eyes were included. 48% were using topical glaucoma medication. Mean baseline IOP was 14.9 ± 4.52 mmHg, with mean visual field mean deviation (±SD) -5.05 ± 5.45 dB. Strong association was found between maximum IOP during mDTC and WDT (r = 0.90, 95% CI 0.82-0.95 p < 0.0001) with agreement (mDTC-WDT) bias -0.82 mmHg, 95% LoA -1.46 to -0.18. During the WDT, mean systolic blood pressure (±SD) increased from 140.0 ± 20.0 to 153.3 ± 24.0 mmHg (p < 0.0001), mean heart rate ( ± SD) reduced from 69.5 ± 11.3 bpm to 63.6 ± 10.0 bpm (p < 0.0001), and temporal iridocorneal angle increased from 29.2 ± 6.0° to 29.6 ± 5.2° (p = 0.04). CONCLUSION: This study presents repeated, observer-masked IOP data showing strong correlation between maximum IOP during mDTC and WDT using multimodal tonometry. This supports WDT as a meaningful alternative to mDTC when investigating diurnal IOP characteristics in clinic, with reduced time requirements and associated costs.

Assessing impaired gastric accommodation in children with functional constipation using the water load test.

BACKGROUND: This study aimed to evaluate gastric accommodation in pediatric patients with functional constipation using the water load test. METHOD: This was a cross-sectional case-control study. Herein, the water load test results of children aged >4 years with functional constipation referred to a Pediatric Gastroenterology Outpatient Clinic (functional constipation group) were compared with those of a control group (without functional constipation or chronic abdominal pain) recruited from two public schools. Clinical manifestations outlined in the Rome IV criteria were used to diagnose functional constipation. Water load tests were performed after 3 h of fasting. For the test, the participants were asked to drink as much water as possible in 3 min. KEY RESULTS: A total of 36 patients and 77 students were included in the functional constipation and control groups, respectively. There was no significant difference in age between the groups (8.6 ± 2.3 years and 8.8 ± 1.8 years in the functional constipation and control groups, respectively). The water load test showed intake volumes of 390 ± 245 mL and 528 ± 219 mL in the functional constipation and control groups, respectively (p = 0.001). The maximum volume in the water load test correlated with the 24 h daily intake of energy (rS = +0.42, p = 0.012), protein (rS = +0.48, p = 0.004), and water (rS = +0.39, p = 0.020) only in the group with functional constipation. CONCLUSIONS & INFERENCES: According to the water load test, gastric accommodation was impaired in children with severe functional constipation. The impairment of gastric accommodation in children with severe functional constipation is related to food intake.

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.

Sodium and water dynamics in the progression of chronic kidney disease: mechanisms and clinical significance.

AIM: Lifestyle modifications can postpone the progression of chronic kidney disease toward its terminal stage. This mini-review aims to explore the impact of salt and water intake on the progression of chronic kidney disease (CKD) and provide insights into the optimal consumption levels to preserve the glomerular filtration rate. METHODS: We reviewed relevant literature to examine the association between salt and water consumption and CKD progression. Our analysis includes discussions on the pathophysiology, findings from clinical trials, and recommended intake guidelines. RESULTS: Sodium intake, often linked to cardiovascular risk and CKD progression, has shown a complex J-shaped association in some studies, leading to uncertainty about the ideal salt intake level. Sodium and fluid retention are key factors contributing to hypertension, a well-established risk factor for CKD progression. Low-sodium diets have demonstrated promise in reducing blood pressure and enhancing the effects of renin-angiotensin-aldosterone system inhibitors in non-dialysis CKD patients. However, a debate persists regarding the independent effect of salt restriction on CKD progression. Despite medical recommendations, salt consumption remains high among CKD patients. Additionally, the role of water consumption in CKD remains controversial despite its established benefits for CKD prevention in the general population. CONCLUSION: Lifestyle modifications involving salt and water intake can influence the progression of CKD. While low-sodium diets have shown potential for mitigating hypertension and proteinuria in non-dialysis CKD patients, their independent impact on CKD progression warrants further investigation. The role of water consumption in CKD remains uncertain, and there is a need for additional research in this area. Clinicians should consider individualized dietary recommendations for CKD patients to help preserve the glomerular filtration rate and improve overall outcomes.

Sweat Characteristics and Fluid Balance Responses During Two Heat Training Camps in Elite Female Field Hockey Players.

We examined the sweat characteristics and fluid balance of elite female field hockey players during two heat training camps. Fourteen elite female field hockey players from the Australian national squad participated in two heat training camps held ∼6 months apart, following winter- (Camp 1) and summer-based training (Camp 2). Daily waking body mass (BM) and urine specific gravity (USG) were collected, along with several markers of sweat and fluid balance across two matches per camp. There was a 19% mean reduction in estimated whole-body sweat sodium concentration from Camp 1 (45.8 ± 6.5 mmol/L) to Camp 2 (37.0 ± 5.0 mmol/L; p < .001). Waking urine specific gravity ≥ 1.020 was observed in 31% of samples, with no significant differences in mean urine specific gravity or BM between camps (p > .05), but with substantial interindividual variation. Intramatch sweat rates were high (1.2-1.8 L/hr), with greater BM losses in Camp 1 (p = .030), resulting in fewer players losing ≥2% BM in Camp 2 (0%-8%), as compared with Camp 1 (36%-43%; p = .017). Our field data suggest that elite female field hockey players experience substantial sweat losses during competition in the heat regardless of the season. In agreement with previous findings, we observed substantial interindividual variation in sweat and hydration indices, supporting the use of individualized athlete hydration strategies.