Level Of Dehydration Research Articles

Occupational Heat Stress Impacts on Health and Productivity in a Steel Industry in Southern India.

BackgroundWorkers laboring in steel industries in tropical settings with high ambient temperatures are subjected to thermally stressful environments that can create well-known risks of heat-related illnesses and limit workers’ productivity.MethodsA cross-sectional study undertaken in a steel industry in a city nicknamed “Steel City” in Southern India assessed thermal stress by wet bulb globe temperature (WBGT) and level of dehydration from urine color and urine specific gravity. A structured questionnaire captured self-reported heat-related health symptoms of workers.ResultsSome 90% WBGT measurements were higher than recommended threshold limit values (27.2–41.7°C) for heavy and moderate workloads and radiational heat from processes were very high in blooming-mill/coke-oven (67.6°C globe temperature). Widespread heat-related health concerns were prevalent among workers, including excessive sweating, fatigue, and tiredness reported by 50% workers. Productivity loss was significantly reported high in workers with direct heat exposures compared to those with indirect heat exposures (χ2 = 26.1258, degrees of freedom = 1, p < 0.001). Change in urine color was 7.4 times higher among workers exposed to WBGTs above threshold limit values (TLVs).ConclusionPreliminary evidence shows that high heat exposures and heavy workload adversely affect the workers’ health and reduce their work capacities. Health and productivity risks in developing tropical country work settings can be further aggravated by the predicted temperature rise due to climate change, without appropriate interventions. Apart from industries enhancing welfare facilities and designing control interventions, further physiological studies with a seasonal approach and interventional studies are needed to strengthen evidence for developing comprehensive policies to protect workers employed in high heat industries.

Near-infrared chemical imaging (NIR-CI) of 3D printed pharmaceuticals

Hot-melt extrusion and 3D printing are enabling manufacturing approaches for patient-centred medicinal products. Hot-melt extrusion is a flexible and continuously operating technique which is a crucial part of a typical processing cycle of printed medicines. In this work we use hot-melt extrusion for manufacturing of medicinal films containing indomethacin (IND) and polycaprolactone (PCL), extruded strands with nitrofurantoin monohydrate (NFMH) and poly (ethylene oxide) (PEO), and feedstocks for 3D printed dosage forms with nitrofurantoin anhydrate (NFAH), hydroxyapatite (HA) and poly (lactic acid) (PLA). These feedstocks were printed into a prototype solid dosage form using a desktop 3D printer. These model formulations were characterized using near-infrared chemical imaging (NIR-CI) and, more specifically, the image analytical data were analysed using multivariate curve resolution-alternating least squares (MCR-ALS). The MCR-ALS algorithm predicted the spatial distribution of IND and PCL in the films with reasonable accuracy. In the extruded strands both the chemical mapping of the components in the formulation as well as the solid form of the active compound could be visualized. Based on the image information the total nitrofurantoin and PEO contents could be estimated., The dehydration of NFMH to NFAH, a process-induced solid form change, could be visualized as well. It was observed that the level of dehydration increased with increasing processing time (recirculation during the mixing phase of molten PEO and nitrofurantoin). Similar results were achieved in the 3D printed solid dosage forms produced from the extruded feedstocks. The results presented in this work clearly demonstrate that NIR-CI in combination with MCR-ALS can be used for chemical mapping of both active compound and excipients, as well as for visualization of solid form variation in the final product. The suggested NIR-CI approach is a promising process control tool for characterization of innovative patient-centred medicinal products.

Microscopic investigation to determine the effect of Beauveria bassiana (Bals.) Vuill. and Cymbopogon citratus (DC.) Stapf. treatment on different life stages of Musca domestica (L.).

Microscopic investigation was done to determine the effect of entomopathogenic fungi, Beauveria bassiana and essential oil of Cymbopogon citratus on different life stages of Musca domestica. Scanning electron microscopy investigation of fungal infected larvae showed sluggish movement, rigor, and failure of body to balance in water. Treated larvae also revealed varied level of cuticle shrinkage and extreme dehydration. Surface of B. bassiana infected pupae showed varied stage of mycelial growth, while the cadaver of adult fly was observed to have extensive fungal growth covering their entire body surface. The application of C. citratus oils on M. domestica larvae resulted in skin shrinkage, spinous cells proliferation and bleb formation, while the treated pupae showed high incidence of incomplete emergence and malformation in emerged adult flies. The current study establishes effect of C. citratus essential oil and B. bassiana infection on different life stages of M. domestica.

Chaparral Shrub Hydraulic Traits, Size, and Life History Types Relate to Species Mortality during California's Historic Drought of 2014.

Chaparral is the most abundant vegetation type in California and current climate change models predict more frequent and severe droughts that could impact plant community structure. Understanding the factors related to species-specific drought mortality is essential to predict such changes. We predicted that life history type, hydraulic traits, and plant size would be related to the ability of species to survive drought. We evaluated the impact of these factors in a mature chaparral stand during the drought of 2014, which has been reported as the most severe in California in the last 1,200 years. We measured tissue water potential, native xylem specific conductivity, leaf specific conductivity, percentage loss in conductivity, and chlorophyll fluorescence for 11 species in February 2014, which was exceptionally dry following protracted drought. Mortality among the 11 dominant species ranged from 0 to 93%. Total stand density was reduced 63.4% and relative dominance of species shifted after the drought. Mortality was negatively correlated with water potential, native xylem specific conductivity, and chlorophyll fluorescence, but not with percent loss in hydraulic conductivity and leaf specific conductivity. The model that best explained mortality included species and plant size as main factors and indicated that larger plants had greater survival for 2 of the species. In general, species with greater resistance to water-stress induced cavitation showed greater mortality levels. Despite adult resprouters typically being more vulnerable to cavitation, results suggest that their more extensive root systems enable them to better access soil moisture and avoid harmful levels of dehydration. These results are consistent with the hypothesis that short-term high intensity droughts have the strongest effect on mature plants of shallow-rooted dehydration tolerant species, whereas deep-rooted dehydration avoiding species fare better in the short-term. Severe droughts can drive changes in chaparral structure as a result of the differential mortality among species.

Mathematical Modelling of Osmotic Dehydration Kinetics of Apple Cubes

Apple cubes were osmotically dehydrated at 25, 40 and 60C, using sucrose or sorbitol, and the mass ratio of sample to solution of 1:4 and 1:10, at atmospheric pressure or vacuum pressure of 150 mbar. Six mathematical models were tested to describe the mass transfer kinetics of water loss (WL) and sugar gain (SG). Crank's, Azuara's, Peleg's, Page's and Weibull's models could fit well the experimental data, but the Penetration model resulted in a poor fit. The mass ratio of sample to solution did not have an influence on the mass transfer kinetics at the atmospheric pressure. The increase of temperature and the use of sorbitol as the osmotic agent resulted in an increase of the osmotic process rate at both pressures used. Therefore, sorbitol is a good alternative to sucrose. The vacuum presented a tendency to increase the initial rate of WL. Practical Applications This work confirms the potential to use sorbitol as an alternative to sucrose as the osmotic agent in OD. Besides presenting low calories, and being less sweet and less cariogenic than sucrose, sorbitol is a prebiotic. It induced an increased process rate, in comparison with sucrose. This is advantageous for a faster OD process. However, the benefit in the process time reduction may not justify the material costs. The mass ratio of sample to solution of 1:4 was identified as an alternative to 1:10 in the OD at the atmospheric pressure, as lower quantities of osmotic solution and, therefore, solute are required to carry out the OD process to the same level of dehydration. This work shows also that simple models, such as Peleg's and Page's, can be used to predict the mass transfer kinetics of WL and SG during OD processes at different conditions.

Sex differences and plasticity in dehydration tolerance: insight from a tropical liverwort.

Adaptations allowing plants to cope with drying are particularly relevant in the light of predicted climate change. Dehydration tolerance (DhT, also dehydration-tolerant) is one such adaptation enabling tissue to survive substantial drying. A great deal of work has been conducted on highly DhT species. However, bryophytes showing less intense and variable DhT are understudied, despite the potential for these species to provide an informative link between highly tolerant and sensitive species. In this study, we tested the degree to which DhT varies across populations and the sexes of a species expected to exhibit a moderate DhT phenotype. To test predicted patterns of tolerance we assessed DhT in males and females of Marchantia inflexa from two distinct habitat types that differ in water availability. Both common garden and field-collected tissue was subjected to drying assays at multiple intensities and recovery was monitored by chlorophyll florescence. Verification studies were conducted to confirm the level of dehydration, the rate of drying and the associated changes in photosynthetic physiology. We confirmed our expectation that M. inflexa is able to tolerate moderate dehydration. We also found that females exhibited higher DhT than males, but populations did not differ in DhT when cultured in a common garden. However, field-collected samples exhibited differences in DhT corresponding to environmental dryness, suggesting plasticity in DhT. By studying a less extreme DhT phenotype we gained insight into how more sensitive (yet still tolerant) organisms cope with dehydration. Additionally, the identified sex-specific variation in DhT may explain ecological patterns such as female-biased sex ratios. Furthermore, plasticity in DhT has the potential to inform management practices aimed at increasing tolerance to drought conditions.

Clinical Practice Guideline for the Treatment of Pediatric Acute Gastroenteritis in the Outpatient Setting

Acute gastroenteritis (AGE) is a common illness in childhood that usually can be treated in the outpatient setting. Inaccurate assessment or delayed treatment of AGE can lead to an increased risk for invasive interventions. A literature search was conducted using PubMed, CINAHL Plus, the Cochrane Library, and Embase. Results of the query were refined to narrow the focus of relevant studies for the provider caring for dehydrated children in the outpatient setting. Use of clinical dehydration scales to assess the level of dehydration and early initiation of oral rehydration therapy promote optimal patient outcomes. Oral rehydration therapy remains the best means of rehydrating, and ondansetron is a safe and effective adjunct to help children with persistent vomiting. The purpose of this practice guideline is to identify best practices for AGE in children older than 6 months with symptoms for less than 7 days who are being cared for in the outpatient setting.

Quantitative Study of the Effects of Dehydration on the Viscoelastic Parameters in the Vocal Fold Mucosa

The goal of this study was to quantify the viscoelastic parameters of the vocal fold mucosa at varying dehydration levels. Healthy canine larynges were obtained postmortem, and the samples were separated from the subglottal wall. The samples were dehydrated in a vacuum dryer. According to the total dehydration time per sample, dehydration levels were divided into four degrees: 0%, 40%, 60%, and 80%. The stepper was set to stretch the sample to a level of 35% strain at the same rate (0.5 mm/s). Data collection was repeated five times under each dehydration condition. The compression resilience, RC% = S'/S*100%, and the hysteresis area were measured according to the stress-strain curves. The varying properties of the samples under different dehydration levels were investigated by fitting the curves. The area of the hysteresis loops observed in the stress-strain curves increased exponentially with dehydration levels, whereas the RC% decreased linearly. For all curves, low-strain stages can be explained by Hooke's law (σ = E0*ε). With increasing levels of dehydration, E0 was shown to increase, whereas the linear range was shortened. High-strain stages resembled exponential rather than the linear curves. And the nonlinear stage of the curve became increasingly apparent in the stress-strain curves of increased dehydration levels. The quantitative results in this study not only provide a numerical reference for future experimental measurements, but also can be used to verify the biphasic model in future studies.

Smart Macroporous IPN Hydrogels Responsive to pH, Temperature, and Ionic Strength: Synthesis, Characterization, and Evaluation of Controlled Release of Drugs.

Fast responsive macroporous interpenetrating polymer network (IPN) hydrogels were fabricated in this work by a sequential strategy, as follows: the first network, consisting of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEM) cross-linked with N,N'-methylenebisacrylamide (BAAm), was prepared at -18 °C, the second network consisting of poly(acrylamide) (PAAm) cross-linked with BAAm, being also generated by cryogelation technique. Both single network cryogels (SNC) and IPN cryogels were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and water uptake. The presence of weak polycation PDMAEM endows the SNCs and the IPNs cryogels with sensitivity at numerous external stimuli such as pH, temperature, ionic strength, electric field, among which the first three were investigated in this work. It was found that the initial concentration of monomers in both networks was the key factor in tailoring the properties of IPN cryogels such as swelling kinetics, equilibrium water content (EWC), phase transition temperature and the response at ionic strength. The pore size increased after the formation of the second network, the swelling kinetics in pure water being comparable with that of the SNC, phase transition temperature being situated in the range 35-36 °C for IPN cryogels. The water uptake at equilibrium (WUeq) abruptly increased at pH < 3.0 in the case of SNCs, whereas the response of IPN cryogels at the decrease of pH from 6.0 to 1.0 was strongly dependent on the gel structure, the values of WUeq being lower at a higher concentration of DMAEM in the first network, the monomer concentration in the second network being about 10 wt %. The pH response was very much diminished when the monomer concentration was high in both networks (15 wt % in the first network, and 21 wt % in the second network). The increase of the ionic strength from 0 up to 0.3 M NaCl led to the decrease of the WUeq, for all cryogels, the level of dehydration being higher and faster for the SNC than for the corresponding IPN cryogel. The release of diclofenac sodium (DS), as a model acidic drug, triggered by pH, temperature, and ionic strength from the IPN cryogels was evaluated. A pulsatile release of DS from the IPN cryogels was presented, with a slower release at 34 °C (below VPTT) and a faster release at 37 and 40 °C (above the VPTT).

Hydration Status of Elite Young Sailors during World Championship Laser 4.7.

Maintenance of fluid homeostasis is essential for health, athletic performance and thermoregulation. Although there are a lot of studies evaluating hydration status in many sports, there are no data concerning hydration levels during sailing events. PURPOSE: To assess hydration status of elite young sailing athletes during the World Championship Laser 4.7. METHODS: 12 young elite male athletes participated in the study (age: 15.8±1.1 y, height: 1.74±0.1 m, weight: 65.1±1.5 kg, body fat: 12.5±3.1%, training age: 7.0±1.2 y). Hydration status was assessed via pre- and post-race urine samples, based on urine specific gravity (USG), and urine color. Measurements and data collection took place at the same time each day, with mean environmental temperature, humidity and wind speed at 23.0±0.8o C, 64-70% and 9±1 knots, respectively. All athletes competed for 130±9 min. RESULTS: Although all sailors were euhydrated after the end of the 1st semifinal race (day 1) (USG=1.017±0.001), a significant body weight loss was observed (-1.4%) despite ad libitum drinking during the race. Hydration indices were significantly elevated during the remaining days, with post-race USG (2nd semifinal race/day 2: 1.024 ±0.001, 1st final/day 3: 1.026±0.001, 2nd final/day 4: 1.027±0.001, p>0.05), post-race urine color (5, 6, and 6) and change in body weight (-2.5, -2.8, and -3%). All measured parameters indicated progressively increasing levels of dehydration for the athletes. CONCLUSION: The data suggested that progressive dehydration was developed throughout the consecutive days of racing and especially during the race. It is of vital importance even for elite athletes to be educated about the importance of euhydration.

Initial blood pressure is associated with stroke severity and is predictive of admission cost and one-year outcome in different stroke subtypes: a SRICHS registry study.

BackgroundTo investigate if initial blood pressure (BP) on admission is associated with stroke severity and predictive of admission costs and one-year-outcome in acute ischemic (IS) and hemorrhagic stroke (HS).MethodsThis is a single-center retrospective cohort study. Stroke patients admitted within 3 days after onset between January 1st and December 31st in 2009 were recruited. The initial BP on admission was subdivided into high (systolic BP ≥ 211 mmHg or diastolic BP ≥ 111 mmHg), medium (systolic BP 111–210 mmHg or diastolic BP 71–110 mmHg), and low (systolic BP ≤ 110 mmHg or diastolic BP ≤ 70 mmHg) groups and further subgrouped with 25 mmHg difference in systole and 10 mmHg difference in diastole for the correlation analysis with demographics, admission cost and one-year modified Rankin scale (mRS).ResultsIn 1173 IS patients (mean age: 67.8 ± 12.8 years old, 61.4 % male), low diastolic BP group had higher frequency of heart disease (p =0.001), dehydration (p =0.03) and lower hemoglobin level (p <0.001). The extremely high and low systolic BP subgroups had worse National Institutes of Health Stroke Scale (NIHSS) score (p =0.03), higher admission cost (p <0.001), and worse one-year mRS (p =0.03), while extremely high and low diastolic BP subgroups had higher admission cost (p <0.01). In 282 HS patients (mean age: 62.4 ± 15.4 years old, 60.6 % male), both low systolic and diastolic BP groups had lower hemoglobin level (systole: p =0.05; diastole: p <0.001). The extremely high and low BP subgroups had worse NIHSS score (p =0.01 and p <0.001, respectively), worse one-year mRS (p =0.002 and p =0.001, respectively), and higher admission cost (diastole: p <0.002).ConclusionsStroke patients with extremely high and low BP on admission have not only worse stroke severity but also higher admission cost and/or worse one-year outcome. In those patients with low BP, low admission hemoglobin might be a contributing factor.

Antibiotic usage for rotaviral diarrhea among children in Libya

Background: In Libya, routine access to rotavirus testing is not available and clinicians treat presumptively, leading to inappropriate treatments. This study describes the management of rotavirus infection among Libyan children in public hospitals. Methods: A prospective cross-sectional study was conducted to describe the management of rotavirus among children in three public hospitals in Libya from August 2012 to April 2013. We reviewed internal documents to determine if protocols were in place to guide management of diarrheal illness. Children under five presenting with diarrhea had stool samples collected and tested for rotavirus. Comparisons of treatments were made by rotavirus status and level of dehydration; mild, moderate and severe. Results: A total of 545 diarrhea patients below 5 years of age were enrolled in the study. Of those, 311 (57%) cases were infected by rotavirus. Treatment was administered without investigating the cause of diarrhea. Intravenous fluids (IVF) treatment was the most common treatment for rotavirus cases and was administered to 306 (98%) of cases. Antibiotics were administered to about 137 (44%) of rotavirus cases. Antibiotics were more likely to be administered with more severe dehydration. Conclusions: Presumptive treatment with antibiotics was very common in Libyan. Protocols for management of diarrheal illness and rotavirus cases in children need to be established for effective treatment.

Impact of postharvest dehydration process of winegrapes on mechanical and acoustic properties of the seeds and their relationship with flavanol extraction during simulated maceration

This study represents the first time that the extraction of phenolic compounds from the seeds is assessed from instrumental texture properties for dehydrated grapes. Nebbiolo winegrapes were postharvest dehydrated at 20°C and 41% relative humidity. During the dehydration process, sampling was performed at 15%, 30%, 45% and 60% weight loss. The extractable fraction and extractability of phenolic compounds from the seeds were determined after simulated maceration. The evolution of mechanical and acoustic attributes of intact seeds was also determined during grape dehydration to evaluate how these changes affected the extraction of phenolic compounds. The extractable content and extractability of monomeric flavanols and proanthocyanidins, as well as the galloylation percentage of flavanols, might be predicted easily and quickly from the mechanical and acoustic properties of intact seeds. This would help in decision-making on the optimal dehydration level of winegrapes and the best management of winemaking of dehydrated grapes.

Optimization of Two-Stage Pressure/Vacuum Swing Adsorption with Variable Dehydration Level for Postcombustion Carbon Capture

To investigate postcombustion capture of CO2 in the presence of water, we developed a pressure/vacuum swing adsorption (P/VSA) cycle model consisting of a system of partial differential algebraic equations incorporating mass and energy balances, the Ergun equation for pressure changes, competitive Langmuir isotherms, and the linear driving force model. Four potential adsorbents, zeolites 13X and 5A and the MOFs HKUST-1 and Ni-MOF-74, are investigated, evaluated, and compared. Using this simulation, a two-stage Skarstrom cycle, coupled with an upstream dehydration unit and a downstream compression unit, is optimized using a nondominant sorting genetic algorithm, NSGA-II, to minimize the overall cost of capturing 90% of CO2 from flue gas at a purity of 90% and compressing it for pipeline transportation at 110 bar. The results show that under dry flue gas conditions, zeolite 13X is the best performing adsorbent with an overall cost of $32.1/ton of CO2. Under humid flue gas conditions, zeolites 13X and 5A per...

Hydration habits in Spanish elite athletes.

Introduction: The concept of dehydration is defined as a risk to the health of athletes and their performance. Many athletes reach very high levels of dehydration due to water loss through sweat and low fluid intake. Objective: This study aims to assess the state of hydration of athletes who come to the consultation by completing a questionnaire about their habits regarding fluid intake. The questionnaire consists of 28 questions on hydration. In addition, information on sports history and personal data of each athlete were required. Method: A sample of 58 athletes participated in the study, 37.9% were men and 62.1% women, with a mean age of 29.1 years (SD = 5.5). They participated voluntarily and data collection was conducted from April to July 2015. Results: The results showed that more experienced athletes presented higher intake of litres of liquid than the less experienced athletes, and this difference approached the statistical significance. This suggests an effect of experience on the hydration of the athletes. More research in this field is necessary.

EFFECTS OF VOLUNTARY INTAKE OF FLUIDS (WATER AND SPORTS DRINK) IN AMATEUR MOUNTAIN RUNNERS

21 K and 1 000 m ascent trail-running races can be dangerous if an appropriate liquid replacement isn't maintained. know trail-runners level of dehydration and assess the differences between ad libitum water (CcA) and sport drink (CcB) hydration after a trail running race. 18 subjects, mean age 31.9 (±2.8) and %MG 10.53 (±2.8), completed CcA or CcB. CcA and CcB effects on Weight (P), Fat Mass (MG), Glucose (GL), Lactate (LT), Systolic (TAS) and Diastolic Arterial Tension (TAD), Heart Rate (PPM) and Tympanic Temperature (Tª) were assessed. All measurements were taken at the start (T1) and the finish (T2) of each race. A Friedman ANOVA test was used to calculate the effect of CcA and CcB on each variable. Differences between race time (TC), % bodyweight loss (%PP) and liquid ingestion (LI) were assessed with a Wilcoxon test. All statistical analysis were conducted with SPSS version 20.0 (IBM, Somers, NY, USA). mean %PP was 2.967 (± 0.969) and 2.883 (± 0.730) for CcA and CcB respectively. No significant differences were found between %PP and LI (p > .05) between races. Significant changes were found in P, %MG, GL, L, TAS and PPM between T1 and T2 in CcA condition. While only significant changes in P and PPM were stabilised between T1 and T2 in CcB condition. neither water or sport drink ingestion avoid trail-runners to reach a dehydrated state. However, dehydration effects seems to be more serious when only water is ingested.

Physical Fitness and Dehydration Influences on the Cardiac Autonomic Control of Fighter Pilots.

Physical fitness and dehydration are factors that may influence cardiac autonomic control. We aimed to verify the influence of these factors on cardiac autonomic control before, during, and after a flight. At the same time of day, 11 healthy fighter pilots recorded several 1-h bouts of heart rate (HR) activity during a non- (control) and a training flight day. Autonomic control of HR was examined via time domain and non-linear heart rate variability (HRV) analyses. The level of dehydration during the flight was evaluated by changes in hematocrit, while aerobic capacity, muscular strength, and body fatness were the physical fitness components evaluated. The flight induced a significant reduction in most parameters of HRV during flight time when compared to the control day. However, no differences were found between the days before the flight, while the root mean square of successive differences (RMSSD) of HR was the only parameter significantly reduced (11.05 ± 7.7%) after the flight. Significant correlations were observed between the sample entropy of HR during flight and aerobic capacity (r = 0.777) and body fatness (r = -0.617). Correlations between dehydration and changes in HRV (RMSSD and SD1) were also identified (r = -0.61 to -0.81). The current results demonstrated significant relationships between aerobic capacity, body fatness, and hydration status on autonomic control of HR during and after flights. No relationship to muscular strength was observed. Future studies may further elucidate the impact of these factors on pilot training in order to accommodate flight's stressors and enhance performance.

Do small differences in hydration status affect mood and mental performance?

Although it has been suggested that many in the general population are dehydrated to the extent that mood and cognition are disrupted, there has been little research investigating mild levels of dehydration. When dehydration reduces body mass by more than 2%, it has been consistently reported that mood is influenced, fatigue is greater, and alertness is lower. In contrast, the effects on cognition have been less consistent. Only a few studies have looked at females and these studies made little attempt to consider hormones that influence kidney functioning. In particular, there has been virtually no attempt to look at changes in hydration status in the range that occurs in individuals with a sedentary lifestyle in a temperate climate. There is a consequent need to study individuals who have lost up to 1% of body mass due to dehydration. While 4 intervention trials have found that the cognition of children improved in response to water consumption, the effects of water consumption on cognition in older adults, another high-risk group, have been largely ignored.

Prevalence of Inadequate Hydration Levels in Aquatic Safety Personnel: A Pilot Study

Lifeguards play an important role in the security and safety of those they are hired to protect. A performance issue may arise if they succumb to circumstances that cause them to become physically or psychologically compromised. Dehydration is one issue that can result in decreased levels of workplace performance and pose personal health risks. Certified lifeguards 15 years old and older were tested for urine specific gravity (USG) to determine their place within the dehydration spec- trum. Participants (N = 55) were recruited from seven test sites offering a variety of designs (indoor/outdoor, traditional/waterpark) and classifications (private, semipublic, public). Testing involved the collection of a urine specimen from participants and immediate recording of specific gravity using a reagent test strip by researchers. A brief survey to collect demographic information from subjects was also administered. The majority of participants were found to reside along the dehydration spectrum (USG ≥ 1.015), several showing results toward the severe end of the scale. The sample provided adequate demographic variability among males and females and facility classification types. No statistically significant differences were found between the demographic variables and USG scores of subjects. Since the majority of lifeguards in the sample showed some level of dehydration, this indicated a need for more information concerning lifeguards and dehydration. Despite the lack of statistically significant differences among the demographic factors within this sample, future studies should incorporate other behavioral factors and dehydration testing methods to investigate the mechanisms for preventing dehydration as well as its impact on lifeguarding performance.

Relationship Between Core Temperature And Dehydration In Boys And Men Exercising In The Heat

The classical work of Bar-Or and colleagues more than 30 years ago suggested that the rise in rectal temperature (Tre) with a given dehydration level induced by exercise is more accentuated in boys compared to men. Such a response, however, may simply reflect the disproportional body heat production (Hp) when different exercise intensities are used to compare thermoregulatory responses between groups of different size. PURPOSE: To compare the relationship between Tre and dehydration level in boys and men, matched for aerobic fitness (VO2peak), during cycling at a similar %VO2peak and at a similar Hp. METHODS: Ten boys (11.5 ± 1.3 yrs, 42.3 ± 9.7 kg and VO2peak = 39.6 ± 7.1 mL.Kg-1.min−1) and 10 men (22.9 ± 2.3 yrs, 71.1 ± 9.7 kg and VO2peak = 40.4 ± 6.5 mL.Kg-1.min−1) cycled 4×20-min bouts at 45% VO2peak (REL) and, in an additional session, only the men cycled at the same absolute Hp as the boys (ABS). All sessions occurred in the heat (35°C and 35% RH) without fluid intake. Tre was measured periodically and [INCREMENT]body mass was used to calculate dehydration. RESULTS:Hp in boys (269 ± 46.1 W) was lower (P < 0.001) compared to men (482.5 ± 94.1 W) during REL but similar during ABS (265.1 ± 41.1 W). Conversely, Hp per Kg body mass was similar between groups during REL and lower in men during ABS (6.5 ± 1.2, 6.8 ± 1.0 and 3.7 ± 0.5 W.Kg−1, respectively, P < 0.001). Initial Tre was similar between groups. [INCREMENT]Tre was similar between boys and men during REL, but lower in men during ABS (0.6 ± 0.2, 0.7 ± 0.2 and 0.3 ± 0.2°C, respectively, P = 0.004). Groups achieved similar dehydration levels (1.6 ± 0.4, 1.9 ± 0.4 and 1.3 ± 0.3 %), regardless of session. There was a significant correlation between [INCREMENT]Tre and % dehydration in boys (r = 0.78, P = 0.007) and men (r = 0.65, P = 0.04) during ABS, but not during REL (r = 0.36, P = 0.30). The degree of dehydration could explain 60.8% and 42.3% of the variance in [INCREMENT]Tre in the boys and men during ABS, respectively. For each 1% of dehydration the [INCREMENT]Tre was equivalent to 0.4o C in boys, 0.2° C in men during REL and 0.4o C during ABS, with the boys’ regression line a constant 0.3° C higher than the men’s during ABS. CONCLUSION: The rate of [INCREMENT]Tre relative to dehydration was similar between boys and men during ABS, but Tre was consistently higher in boys. No thermoregulatory disadvantage was observed in boys compared to men during REL. Supported by a student award from the GSSI.