Hydration Markers Research Articles

Plasma and serum volume remain unchanged following a 12-h fast from food and drink despite changes in blood and urinary hydration markers.

The effect of mild dehydration on plasma and serum volume has not been well established. Furthermore, the ability of urinary and blood biomarkers to monitor small hydration changes have not been solidified. There were two objectives of this research: 1. Determine if mild dehydration affects plasma and serum volume; 2. Determine if mild dehydration can be detected better by urinary or blood biomarkers. 47 subjects were recruited; 10 subjects were removed from the study and 37 subjects (27% male) completed the study. This was a crossover study design such that each subject underwent all protocols in a counterbalanced order. Protocols consisted of 12-h dehydration, 12-h hydration, and control. Neither plasma volume (p = 0.914), plasma volume status (p = 0.649), nor serum volume (p = 0.273) were different among protocols. Body mass (p < 0.001) was lower following the dehydration protocol. Urine color (p < 0.001), urine osmolality (p < 0.001), urine specific gravity (p < 0.001), serum osmolality (p < 0.001), and plasma osmolality (p < 0.001) were all lower following the hydration protocol. Hematocrit (p = 0.842) and hemoglobin concentration (p = 0.558) were not different among protocols. Dehydration did not affect plasma or serum volume. Therefore, a 12-h fast from food and water as done in this study will not likely affect laboratory test results of biomarker concentration. All 3 urinary measures were able to detect changes in hydration status, whereas only 2 blood measures were able to detect changes in hydration status. This may indicate that urinary measures are best at detecting small changes in hydration status.

Hydration Considerations to Improve the Physical Performance and Health of Firefighters.

Background/Objectives: Firefighters are exposed to a high level of stress as they often perform physically challenging work in hazardous environments while responsible for rescuing and keeping those around them safe. To add to this stress, they are also required to work in heavy, unbreathable personal protective equipment which promotes dehydration. These occupational demands paired with dehydration may lead to increased core temperatures, cardiac strain, and overall risk for sudden cardiac events. Thus, it is important to include hydration assessments and determine fluid needs when firefighters are on shift to ensure their personal safety as well as the safety of those around them by optimizing physical performance by maintaining adequate hydration. Therefore, the purpose of this review is to identify markers of hydration, classifications of hydration status, current hydration recommendations, and hydration interventions that may contribute to the overall clarity of hydration protocols that may optimize performance and health of firefighters. In addition, the impact of common medications, exercise training, and health conditions on hydration status related to firefighters will be discussed. Methods: A comprehensive literature search was conducted to discuss the purpose statements. Results: Hydration recommendations for firefighters include (1) assessing hydration status with multiple measurements including body mass, urine specific gravity and thirst sensation, and (2) following general hydration recommendations on rest days and exercise hydration protocols during firefighting activities which may be altered according to hydration status measurements. Conclusion: Randomized controlled trials in firefighters are needed to determine the impact of maintaining adequate hydration on health markers.

Risk for hypertension and heart failure linked to high normal serum sodium and tonicity in electronic medical records.

Population aging is fueling an epidemic of age-related chronic diseases. Managing risk factors and lifestyle interventions have proven effective in disease prevention. Epidemiological studies have linked markers of poor hydration with higher risk of chronic diseases and premature mortality. Many individuals do not adhere to recommended hydration levels and could benefit from improved hydration habits. Our study evaluates the use of electronic medical records to confirm the relationship between inadequate hydration and the risk of chronic diseases, which may inform hydration-focused interventions in general healthcare. We analyzed 20-year electronic medical records for 411,029 adults from Israel's Leumit Healthcare Services. Hydration status was assessed using serum sodium and tonicity. We included adults without significant chronic diseases or water balance issues, defined as having normal serum sodium (135-146 mmol/l) and no diagnosis of diabetes. We used Cox proportional hazards models, adjusted for age, to assess the risk of developing hypertension and heart failure. Our findings showed an increased risk of hypertension with elevated serum sodium levels: a 12% rise for the 140-142 mmol/l group and 30% for levels above 143 mmol/l (HR1.30, 95%CI:1.26-1.34). Tonicity over 287 mosmol/kg was associated with a 19% increased risk of hypertension (HR1.19, 95%CI:1.17-1.22). The risk of heart failure also increased, reaching 20% for sodium levels above 143 mmol/l (HR1.20,95%CI:1.12-1.29) and 16% for tonicity above 289 mosmol/kg (HR1.16, 95%CI: 1.10-1.22). The association between sodium and hypertension was observed across genders, while the risk of heart failure was more pronounced in females. Within the healthy Leumit cohort, 19% had serum sodium levels within the 143-146 mmol/l range, and 39% were in the 140-142 mmol/l range. Data analysis from electronic medical records identified a link between serum sodium of 140 mmol/l and above and increased risk of hypertension and heart failure in the general Israeli population. Identifying individuals with high-normal sodium values in healthcare records could guide improvements in hydration habits, potentially leading to better health outcomes.

Sleep, Health Outcomes and Body Weight (SHOW) study: a measurement burst design study on sleep and risk factors for obesity in black emerging adults in North Carolina, USA

IntroductionBlack emerging adults (18–28 years) have the highest risk of short sleep duration and obesity. This increased risk may be partly explained by greater stress levels, which may result from...

A randomized controlled trial evaluating the effect of providing a rest period during long-distance transportation of surplus dairy calves: Part II. Effect on hematological variables

The objective of this randomized controlled trial was to determine if providing a rest stop including provision of feed and water between periods of continuous transportation mitigates the effect of long-distance transportation on markers of energy status and hydration in calves transported by road for 16 h. This study was conducted between September 2022 to January 2023 and included male and female Holstein and crossbred dairy calves ≥7 d old from 2 commercial dairy farms in Ontario, Canada (n = 96). On the day before transportation, calves were enrolled and randomly assigned to one of 2 treatment groups: (1) continuous transportation by road for 16 h or (2) 8 h of transport, 8 h of rest, and a further 8 h of transport to a single calf-raising facility. Calves that received a rest stop were fed 2 L of milk replacer at the time of unloading for the rest period and again immediately before reloading for the second leg of the journey. Blood samples were collected before and after transportation as well as daily for 3 d following arrival to the calf-raising facility. Serum was analyzed for concentrations of BHB, nonesterified fatty acids (NEFA), haptoglobin, and creatine kinase, and acid-base disturbances were evaluated within 1 h of collection of whole blood to assess glucose, sodium, potassium, ionized calcium, hematocrit, hemoglobin, pH, base excess, partial pressure of oxygen, total carbon dioxide, bicarbonate, partial pressure of carbon dioxide, and oxygen saturation. Mixed linear regression models with repeated measures were built to assess the effect of treatment group, age at transportation, breed, and sex on these parameters. Immediately after transportation, calves that received the rest period had lower BHB (-68.04 μmol/L, 95% CI: -99.59 to -36.49), NEFA (-0.14 mmol/L, 95% CI -0.22 to -0.07), and sodium (-1.10 mmol/L, 95% CI = -2.18 to -0.02), and higher glucose (0.48 mmol/L, 95% CI = 0.21 to 0.74), potassium (0.27 mmol/L, 95% CI = 0.11 to 0.43), ionized calcium (0.06 mmol/L, 95% CI = 0.03 to 0.08), and oxygen saturation (8.76%, 95% CI = 1.61 to 15.91) compared with calves that were continuously transported for 16 h. Additionally, calves transported between 11 and 12 d old had lower hematocrit (-1.22%, 95% CI = -2.19 to -0.25), hemoglobin (-3.07 g/L, 95% CI = -5.70 to -0.43), haptoglobin (-0.13 g/L, 95% CI = -0.23 to -0.02), and potassium (-0.13 mmol/L, 95% CI = -0.22 to -0.04) and higher sodium (0.83 mmol/L, 95% CI = 0.03 to 1.63) than 7 to 8 d old calves. Furthermore, calves that were 13 to 24 d old at transport had lower haptoglobin (-0.16 g/L, 95% CI = -0.27 to -0.06) and potassium (-0.14 mmol/L, 95% CI = -0.23 to -0.05), and higher sodium (1.02 mmol/L, 95% CI = 0.22 to 1.82) and ionized calcium (0.02 mmol/L, 95% CI = 0.002 to 0.035) compared with calves transported at 7 to 8 d old. The results of this trial demonstrate that a rest period improves energy status upon arrival to a calf-raising facility, suggesting that the benefit of a rest period may be mostly related to the provision of mid-journey milk meals.

The short-term effect of apparent temperature on the hydration marker plasma sodium

The short-term effect of apparent temperature on the hydration marker plasma sodium

Sports drinks do not increase acute kidney injury risk in males during industrial work in the heat when euhydration is maintained, a randomized crossover trial.

Industrial workers regularly perform physical labor under high heat stress, which may place them at risk for dehydration and acute kidney injury. Current guidelines recommend that workers should consume sports drinks to maintain euhydration during work shifts. However, the impact of fructose sweetened sports drinks on acute kidney injury risk is unknown. The purpose of this study was to investigate the effects of sports drink consumption on markers of acute kidney injury following simulated industrial work in the heat. Twenty males completed two matched 2 h simulated industrial work trial visits in a warm and humid environment (30°C and 55% relative humidity). During and following the bout of simulated work, participants consumed either a commercially available sports drink or a noncaloric placebo. Urine and blood samples, collected pre-, post-, and 16 h post-work were assayed for markers of hydration (plasma/urine osmolality, and urine specific gravity) and acute kidney injury (KIM-1 and NGAL). There were no differences in physiological or perceptual responses to the bout of work (interaction p>0.05 for all indices), and markers of hydration were similar between trials (interaction p>0.05 for all indices). KIM-1 (Placebo: Δ Ln 1.18±1.64; Sports drink: Δ Ln 1.49±1.10 pg/mL; groupwide d=0.89, p<0.001) and NGAL (Placebo: Δ Ln 0.44±1.11; Sports drink: Δ Ln 0.67±1.22 pg/mL; groupwide d=0.39, p=0.03) were elevated pre- to post-work, but there were no differences between trials (interaction p>0.05). These data provide no evidence that consumption of fructose sweetened sports drinks increases the risk of acute kidney injury during physical work 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.

Dehydration associates with lower urinary tract symptoms in progressive multiple sclerosis.

Lower urinary tract symptoms (LUTS) are common in persons with progressive multiple sclerosis (pwPMS), who may consequently limit their fluid intake. We aimed to investigate the hypothesis that LUTS associate with objective evidence of inadequate hydration status in pwPMS. In this prospective study, 55 pwPMS were studied over 2 years. A 6-monthly first-morning urine specimen was analysed for urinary osmolality and sodium as hydration markers. LUTS symptom severity in three categories (urgency, voiding and discomfort) was assessed and quantified using a questionnaire. Correlation between LUTS severity and hydration was assessed within subjects and between subjects, controlling for age. Some 274 urine samples with accompanying LUTS data from 55 participants were analysed. Biochemical data showed the expected loss of urine-concentrating capacity with increasing age. Inadequate hydration was observed in 47% of participants. LUTS were very common (87% reported urgency and 89% voiding symptoms). Voiding and discomfort, but not urgency severity, were correlated with hydration markers, both within and between participants. LUTS are very common in pwPMS, and associate with inadequate hydration. The causes and consequences of inadequate hydration in MS need further study, since (i) this will focus greater attention on LUTS management in pwPMS and (ii) dehydration has been associated with reversible cognitive dysfunction and physical underperformance.

Literature Review Hydration Assessment Methods in the Elderly Population: Advantages and Disadvantages

Background: The elderly population is vulnerable to hydration problems, which can have adverse effects on their health. Accurate and reliable hydration assessment methods are crucial for effective detection, monitoring, and management of hydration status in the elderly. However, there is currently no consensus on the optimal method.&#x0D; Objectives: This literature aims to analyze the hydration assessment methods used in the elderly population and evaluate their strengths and limitations.&#x0D; Methods: This study gathered data from relevant literature and research articles obtained from journals in databases such as PubMed, Google Scholar, and Science Direct. Articles were searched using keywords such as Hydration Assessment, Hydration Markers, and (elderly OR older). Data sources included publications from official websites and research journals. The literature review process involved selecting the review topic, searching for relevant articles, and analyzing and synthesizing the available literature.&#x0D; Discussion: Several hydration assessment methods in the elderly include biochemical parameters, clinical signs and symptoms, bioimpedance analysis (BIA), and ultrasonography. However, no single method can provide a comprehensive picture of dehydration status in the elderly.&#x0D; Conclusions: When selecting an appropriate assessment method, factors such as assessment goals, strengths, limitations, sensitivity, specificity, cost, equipment availability, ease of use, and time required need to be considered. By considering these factors, researchers can choose the most suitable hydration assessment method for the elderly population, thereby obtaining accurate and relevant information for proper management and care.

The weight, urine colour and thirst Venn diagram is an accurate tool compared with urinary and blood markers for hydration assessment at morning and afternoon timepoints in euhydrated and free-living individuals.

The weight, urine colour and thirst (WUT) Venn diagram is a practical hydration assessment tool; however, it has only been investigated during first-morning. This study investigated accuracy of the WUT Venn diagram at morning and afternoon timepoints compared with blood and urine markers. Twelve men (21 ± 2 years; 81·0 ± 15·9 kg) and twelve women (22 ± 3 years; 68·8 ± 15·2 kg) completed the study. Body mass, urine colour, urine specific gravity (USG), urine osmolality (UOSM), thirst and plasma osmolality (POSM) were collected at first-morning and afternoon for 3 consecutive days in free-living (FL) and euhydrated states. Number of markers indicating dehydration levels were categorised into either 3, 2, 1 or 0 WUT markers. Receiver operating characteristics analysis calculated the sensitivity and specificity of 1, 2 or 3 hydration markers in detecting dehydration or euhydration. Specificity values across morning and afternoon exhibited high diagnostic accuracy for USG (0·890-1·000), UOSM (0·869-1·000) and POSM (0·787-0·990) when 2 and 3 WUT markers were met. Sensitivity values across both timepoints exhibited high diagnostic accuracy for USG (0·826-0·941) and UOSM (0·826-0·941), but not POSM in the afternoon (0·324) when 0 and 1 WUT markers were met. The WUT Venn diagram is accurate in detecting dehydration for WUT2 and WUT3 based off USG, UOSM and POSM during first-morning and afternoon. Applied medical, sport and occupational practitioners can use this tool in field settings for hydration assessment not only at various timepoints throughout the day but also in FL individuals.

Effects of a 1-hour per night week-long sleep extension in college students on cardiometabolic parameters, hydration status, and physical activity: A pilot study

ObjectivesShort sleep duration is associated with poor physical health in college students. Few studies examine the effects of sleep extension on physical health in this population, who are susceptible to sleep loss. We examined health effects of a 1-week, 1-hour nightly sleep extension in college students. MethodsTwelve healthy undergraduate college students (83% female; age 20.2 ± 1.5years) completed a study consisting of sleeping typically for 1week (“Habitual”), then extending sleep by ≥1 hour/night during the second week (“Extension”). Sleep and physical activity actigraphy were collected throughout. Following each week, participants completed cardiometabolic assessments including a meal response and provided a urine sample for markers of hydration. ResultsIn Extension compared to Habitual, average sleep duration increased (mean change±SEM, +42.6 ± 15.1 minutes; p = .005), while subjective sleepiness (−1.8 ± 0.8 units; p = .040), systolic blood pressure (−6.6 ± 2.8 mmHg; p = .037), postprandial glucose area under the curve (−26.5 ± 10.2 mg/dL × h; p = .025) and time to baseline (−83.0 ± 46.4 minutes; p = .031) after the meal response, sedentary time (−44.3 ± 15.7 minutes; p = .018), and percentage of wake in moderate-to-vigorous activity (−0.89% ± 0.35%; p = .030) decreased. Participants who increased average sleep duration by ≥20 minutes (n = 9) were better hydrated according to urine osmolality (−187.0 ± 68.4 mOsm/kg; p = .026) and specific gravity (−0.01 ± 0.002 g/mL; p = .012) and had reduced odds of dehydration according to urine osmolality (≥800 mOsm/kg; −67%; OR=0.03; p = .035). ConclusionsThis pilot study's findings suggest that sleep extension may improve cardiometabolic functioning and hydration, and alter sedentary behavior and physical activity, in college students. Sleep extension may be employed to improve multiple aspects of health in this sleep-deprived population.

Vaping-Induced Proteolysis Causes Airway Surface Dehydration.

Proteases such as neutrophil elastase cleave and activate the epithelial sodium channel (ENaC), causing airway dehydration. Our current study explores the impact of increased protease levels in vapers' airways on ENaC activity and airway dehydration. Human bronchial epithelial cultures (HBECs) were exposed to bronchoalveolar lavage fluid (BALF) from non-smokers, smokers and vapers. Airway surface liquid (ASL) height was measured by confocal microscopy as a marker of hydration. ENaC cleavage was measured by Western blotting. Human peripheral blood neutrophils were treated with a menthol-flavored e-liquid (Juul), and the resulting secretions were added to HBECs. BALF from smokers and vapers significantly and equally increased ENaC activity and decreased ASL height. The ASL height decrease was attenuated by protease inhibitors. Non-smokers' BALF had no effect on ENaC or ASL height. BALF from smokers and vapers, but not non-smokers, induced ENaC cleavage. E-liquid-treated neutrophil secretions cleaved ENaC and decreased ASL height. Our study demonstrated that elevated protease levels in vapers' airways have functional significance since they can activate ENaC, resulting in airway dehydration. Lung dehydration contributes to diseases like cystic fibrosis (CF), chronic obstructive pulmonary disease (COPD) and asthma. Thus, our data predict that vaping, like smoking, will cause airway surface dehydration that likely leads to lung disease.

Differences in selected blood parameters between brachycephalic and non-brachycephalic dogs.

Cranial and upper-airway anatomy of short-nosed, flat-faced brachycephalic dogs predisposes them to brachycephalic obstructive airway syndrome (BOAS). Periodic apnoea increased inspiratory resistance, and an inability to thermoregulate effectively are characteristic of BOAS, but internationally accepted objective markers of BOAS severity are missing. The objective of this study was to compare the selected blood parameters between non-brachycephalic (NC) and brachycephalic (BC) dogs, exploring the possibility of developing a blood test for BOAS severity grading in the future. We evaluated blood biochemistry, complete blood cell counts, red blood cell (RBC) indices, reticulocyte counts, a blood-born marker of intermittent hypoxia (glutathione, NO production), RBC hydration, deformability, and blood markers of metabolic changes and stress between BC (n = 18) and NC (meso- and dolichocephalic, n = 22) dogs. Reticulocyte counts and the abundance of middle-fluorescence immature reticulocytes were significantly (p < 0.05) higher in BC dogs compared to NC dogs. BC dogs had significantly more NO-derived NO/NO in plasma than NC dogs. RBCs of BC dogs were shedding significantly more membrane, as follows from the intensity of eosin maleimide staining, and had a significantly higher mean corpuscular hemoglobin concentration than NC dogs. Intracellular reduced glutathione content in RBCs of BC dogs was significantly lower, while plasma lactate was significantly higher in BC dogs compared to NC dogs. Plasma cholesterol and triglycerides were significantly lower, and cortisol was significantly higher in BC dogs compared to NC dogs. Eosinophil counts were significantly lower and the neutrophil-to-lymphocyte ratio was higher in BC dogs compared to NC dogs. Taken together, our findings suggest that the brachycephalic phenotype in dogs is associated with alterations at the level of blood cells and, systemically, with oxidation and metabolic changes. The parameters identified within this study should be further investigated for their potential as objective indicators for BOAS.

Short-term association between outdoor temperature and the hydration-marker copeptin: a pooled analysis in five cohorts

Whereas outdoor temperature is linked to both mortality and hydration status, the hormone vasopressin, measured through the surrogate copeptin, is a marker of cardiometabolic risk and hydration. We recently showed that copeptin has a seasonal pattern with higher plasma concentration in winter. Here, we aimed to investigate the association between outdoor temperature and copeptin. Copeptin was analysed in fasting plasma from five cohorts in Malmö, Sweden (n=26,753, 49.7% men, age 18-86 years). We utilized a multivariable adjusted non-linear spline model with four knots to investigate the association between short-term temperature (24h mean apparent) and log copeptin z-score. We found a distinct non-linear association between temperature and log copeptin z-score, with both moderately low and high temperatures linked to higher copeptin concentration (p<0.0001). Between 0°C and nadir at the 75th temperature percentile (corresponding to 14.3°C), log copeptin decreased 0.13 z-scores (95% CI 0.096; 0.16), which also inversely corresponded to the increase in z-score log copeptin between the nadir and 21.3°C. The J-shaped association between short-term temperature and copeptin resembles the J-shaped association between temperature and mortality. Whereas the untangling of temperature from other seasonal effects on hydration warrants further study, moderately increased water intake constitutes a feasible intervention to lower vasopressin and might mitigate adverse health effects of both moderately cold and hot outdoor temperatures. Swedish Research Council, Å Wiberg, M Stephen, A Påhlsson, Crafoord and Swedish Heart-Lung Foundations, Swedish Society for Medical Research and Swedish Society of Medicine.

Water consumption patterns impact hydration markers in males working in accordance with the National Institute for Occupational Safety and Health recommendations

The impact of water consumption bolus volume and frequency on hydration biomarkers during work in the heat is unknown. In a randomized, crossover fashion, eight males consumed either 500 mL of water every 40 min or 237 mL of water every 20 min during 2 hr of continuous walking at 6.4 kph, 1.0% grade in a 34 °C/30% relative humidity environment, followed by 2 hr of rest. Hydration biomarkers and variables were assessed pre-work, post-work, and after the 2 hr recovery. There were no differences in body mass between trials at any time point (all p > 0.05). Percent change in plasma volume during work was not different when 237 mL of water was repeatedly consumed (−1.6 ± 8.2%) compared to 500 mL of water (−1.3 ± 3.0%, p = 0.92). Plasma osmolality was maintained over time (p = 0.55) with no difference between treatments (p = 0.21). When consuming 500 mL of water repeatedly, urine osmolality was lower at recovery (205 ± 108 mOsmo/L) compared to pre-work (589 ± 95 mOsmo/L, p < 0.01), different from repeatedly consuming 237 mL of water which maintained urine osmolality from pre-work (548 ± 144 mOsmo/L) through recovery (364 ± 261 mOsmo/L, p = 0.14). Free water clearance at recovery was greater with repeated consumption of 500 mL of water (1.2 ± 1.0 mL/min) compared to 237 mL of water (0.4 ± 0.8 mL/min, p = 0.02). Urine volume was not different between treatments post-work (p = 0.62), but greater after 2 hr of recovery when repeatedly consuming 500 mL of water compared to 237 mL (p = 0.01), leading to greater hydration efficiency upon recovery with repeated consumption of 237 mL of water (68 ± 12%) compared to 500 mL (63 ± 14%, p = 0.01). Thirst and total gastrointestinal symptom scores were not different between treatments at any time point (all p > 0.05). Body temperatures and heart rate were not different between treatments at any time point (all p > 0.05). Drinking larger, less frequent water boluses or drinking smaller, more frequent water boluses are both reasonable strategies to promote adequate hydration and limit changes in body mass in males completing heavy-intensity work in the heat.

Protective effect of Schizonepeta tenuifolia Briq. ethanolic extract against UVB-induced skin aging and photodamage in hairless mice.

The purpose of this study was to illuminate the mechanism by which Schizonepeta tenuifolia Briq. (ST) ethanolic extract prevents skin photoaging in HR-1 hairless mice (HR-1). The ST ethanolic extract alleviated wrinkle formation, epidermal skin thickness, and collagen degradation in skin tissues of ultraviolet B (UVB)-irradiated HR-1 mice. Expression of matrix metalloproteinases (a wrinkle-related marker) was reduced, and tissue inhibitor of metalloproteinase 1 expression was upregulated following application of ST ethanolic extract. Furthermore, skin dehydration and levels of hyaluronidase-1 and -2 (enzymes that break hyaluronic acid) were decreased. Moreover, protein expression of hyaluronan synthases (markers of skin hydration) and hyaluronic acid levels increased following ST ethanolic extract treatment in UVB-induced photoaging HR-1 mice. In addition, the phosphorylation of mitogen-activated protein kinases (MAPKs), including p38, extracellular signal-regulated kinase, and Jun N-terminal kinase was suppressed, and expression of nuclear factor-kappa was reduced. Treatment with ST ethanolic extract also reduced advanced glycation end product (AGE) accumulation and expression of the receptor for AGE (RAGE) in skin tissue. These results suggest that ST ethanolic extract moderates skin damage caused by UVB irradiation via regulating the expression of wrinkle- and hydration-related proteins, MAPKs, and RAGE.

0198 Effects of a 1-hour nightly weeklong sleep extension pilot study in undergraduates on health

Abstract Introduction Sleep restriction impairs health, but less is known about the potential health benefits of extending sleep in undergraduate students with habitual short sleep. This study examined the effects of a 1-week, 1-hour per night sleep extension on cardiometabolic health, hydration status, sedentary behavior, and physical activity in undergraduate students. Methods Twelve healthy undergraduate students (83% female; mean±SD age 20.2±1.5; range 18-23 years) obtaining fewer than 7 hours of average nightly sleep completed a two-week study. The first week consisted of sleeping typically ("Habitual"), followed by a peer-delivered intervention to extend time in bed by ≥1 hour/night during the second week ("Extension"). Sleep and physical activity actigraphy were collected throughout. Following each week, participants completed in-person cardiometabolic assessments, including a standardized meal response procedure and blood pressure measurement. Blood samples for measurement of glucose and insulin were collected before, during, and following a standardized breakfast. Urine samples yielded markers of hydration (specific gravity and osmolality). Mixed-effects regression models with random intercepts for individuals compared outcomes after the Extension week to Habitual outcomes. Results Compared to Habitual sleep, average sleep duration across the Extension week increased (b±SEM, +42.6±.3 minutes; p=.005). After the breakfast meal, glucose area under the curve (AUC; −26.5±10.2 mg/dL*h; p=.025) and time to return to baseline levels (−83.0±46.4 minutes; p=.031) decreased following Extension. There was no change in insulin AUC. Systolic blood pressure decreased (−6.6±2.8 mmHg; p=.037) after Extension. Average time spent in sedentary behavior (−44.3±15.7 minutes; p=.018) and percentage of wake spent in moderate-to-vigorous physical activity (−1%±.4%; p=.030) decreased across the Extension week. Participants who increased average sleep duration ≥15 minutes (n=9) were better hydrated according to urine osmolality (−187.0±68.4 mOsm/kg; p=.026) and specific gravity (−.01±.002 g/mL; p=.012) and had lowered odds of dehydration according to urine osmolality (≥800 mOsm/kg; −67%; OR=.03; p=.035). Conclusion This pilot study provided evidence that sleep extension may improve cardiometabolic health and hydration and reduce both sedentary behavior and moderate-to-vigorous physical activity. Future research in randomized controlled trials should examine if such findings extrapolate to larger samples and older populations. Support (if any) CRC/CTSI: UL1-TR002014; pilot grant to AMC from the Department of Biobehavioral Health, Pennsylvania State University

A Randomized, Single-Blind, Crossover Study to Evaluate the Efficacy of a Novel Dietary Supplement Blend with L-Citrulline on Biomarkers of Hydration, Muscle Size, Affect, Inflammation, and Muscular Endurance

Introduction: Citrulline is a non-essential amino acid that has previously been shown to improve athletic performance, reduce fatigue, and increase blood flow. The purpose of this study was to examine the efficacy of a novel dietary supplement blend (3D PUMP BREAKTHROUGH®, 3DPump) vs. citrulline alone on changes in muscle volume, fluid shifts, markers of hydration, inflammation, recovery, affect, and muscular endurance. Methods: Twenty-eight recreationally active subjects (6 women, 22 men) participated in a randomized, positive-controlled, single-blind, crossover study which involved 4 testing visits (2 workout visits each with a 24-hr follow-up visit). Participants ingested 3DPump (containing 3g L-citrulline, 1.2g glycerol, 165mg Amla fruit extract) or 8g of L-citrulline alone 45min before an aerobic and resistance training workout. Assessments of body fluid shifts (via BIA), markers of hydration (urine and serum osmolality, USG, hemoglobin), and appendicular girth were taken before and after exercise while markers of damage and inflammation (neutrophils, CK, ESR, MCP-1, CRP) were taken before and 24 hours after exercise, muscular endurance (reps to failure) was assessed during resistance exercises, and subjective measures of affect and recovery were taken before, after and 24 hours after exercise. Mixed factorial ANOVAs with dependent t-tests were used to compare treatments. Results: A significant interaction occurred for right thigh circumference; however post hoc testing indicated both groups increased similarly in post workout girth (p&lt;0.05). A significant interaction occurred for ECF/TBW indicating post workout was greater than pre workout in 3DPump only (p=0.002). An interaction trend (p≤0.010) occurred for SBP and DBP indicating that 3DPump was uniquely able to significantly lower blood pressure (SBP and DBP) post workout compared to baseline and 24 hours after exercise (p&lt;0.001). Conclusions: 3DPump, which contains 3g L-citrulline was able to provide similar effects in muscular endurance, muscle pump and other subjective feelings of affect, hydration, damage and inflammation markers, and body fluid shifts as an 8g dose of L-citrulline alone. 3DPump may have unique benefits on improving post exercise vascular tone and ECF/TBW.

Comparison of Two Reminder Interventions to Achieve Adequate Water Intake and Hydration in Women: A Pilot Study

Introduction: This pilot study examined the effectiveness of two different 5-week reminder interventions to achieve adequate water intake and hydration in women as well as the effects of body composition and self-efficacy on hydration. Methods: Twenty-two apparently healthy adult women were randomly assigned to the 64 oz. motivational water bottle group (n = 11), or the water reminder – daily tracker app group (n = 11). Body composition, predicted VO2max, and self-efficacy were assessed at baseline, post 5-week intervention, and after a 30-day follow-up period. Urine markers (color, specific gravity, and pH) were reported at baseline, weekly throughout the 5-week intervention, and the last 3 days of the 30-day follow-up period. During the interventions, participants self-reported daily step count, resting heart rate, water intake, and symptoms of dehydration. Results: Both 5-week reminder interventions successfully increased water intake by an average of 29% with a mean daily consumption of 72.05 + 18.75 ounces, meeting recommendations. Based on regression analysis, self-efficacy predicted daily water intake at the end of the 5-week intervention (p = 0.03). Urine markers of hydration classified several participants as dehydrated at the end of 5 weeks. In addition, there was a significant inverse relationship between BMI and Ucol at baseline (p = 0.05), week 5 (p = 0.05), and follow-up (p = 0.04), indicating that women with a higher BMI were more dehydrated. In hydrated participants, memory and ability to concentrate significantly improved (p = 0.019). Results indicated there were no significant differences in water intake and hydration between the two groups at baseline, week 5, and follow-up. Conclusions: Both 5-week interventions successfully increased water intake. However, based on urine markers of hydration women may be more prone to involuntary, chronic dehydration due to a higher body fat percentage.