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Mazumder H, Mondol MH, Rahman M, Khan R, Doza S, Unicomb L, Jahan F, Mukhopadhyay A, Makris KC, Caban-Martinez A, Iqbal R, Ahmed F, Creencia L, Shamsudduha M, Mzayek F, Jia C, Zhang H, Musah A, Fleming LE, Mou X, Kovesdy CP, Gribble MO, Naser AM. Sex-Specific Association of Ambient Temperature With Urine Biomarkers in Southwest Coastal Bangladesh. Kidney Int Rep 2024; 9:1860-1875. [PMID: 38899224 PMCID: PMC11184407 DOI: 10.1016/j.ekir.2024.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/23/2024] [Accepted: 03/04/2024] [Indexed: 06/21/2024] Open
Abstract
Introduction Men are vulnerable to ambient heat-related kidney disease burden; however, limited evidence exists on how vulnerable women are when exposed to high ambient heat. We evaluated the sex-specific association between ambient temperature and urine electrolytes, and 24-hour urine total protein, and volume. Methods We pooled a longitudinal 5624 person-visits data of 1175 participants' concentration and 24-hour excretion of urine electrolytes and other biomarkers (24-hour urine total protein and volume) from southwest coastal Bangladesh (Khulna, Satkhira, and Mongla districts) during November 2016 to April 2017. We then spatiotemporally linked ambient temperature data from local weather stations to participants' health outcomes. For evaluating the relationships between average ambient temperature and urine electrolytes and other biomarkers, we plotted confounder-adjusted restricted cubic spline (RCS) plots using participant-level, household-level, and community-level random intercepts. We then used piece-wise linear mixed-effects models for different ambient temperature segments determined by inflection points in RCS plots and reported the maximum likelihood estimates and cluster robust standard errors. By applying interaction terms for sex and ambient temperature, we determined the overall significance using the Wald test. Bonferroni correction was used for multiple comparisons. Results The RCS plots demonstrated nonlinear associations between ambient heat and urine biomarkers for males and females. Piecewise linear mixed-effects models suggested that sex did not modify the relationship of ambient temperature with any of the urine parameters after Bonferroni correction (P < 0.004). Conclusion Our findings suggest that women are as susceptible to the effects of high ambient temperature exposure as men.
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Affiliation(s)
- Hoimonty Mazumder
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
| | - Momenul Haque Mondol
- School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada; Department of Statistics, University of Barishal, Barishal-8254, Bangladesh
| | - Mahbubur Rahman
- International Centre for Diarrheal Disease Research, Bangladesh, Bangladesh
| | - Rizwana Khan
- International Centre for Diarrheal Disease Research, Bangladesh, Bangladesh
| | - Solaiman Doza
- Environmental and Occupational Health, School of Biological and Population Health Sciences, Oregon State University, Oregon, USA
| | - Leanne Unicomb
- International Centre for Diarrheal Disease Research, Bangladesh, Bangladesh
| | - Farjana Jahan
- International Centre for Diarrheal Disease Research, Bangladesh, Bangladesh
| | - Ayesha Mukhopadhyay
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
| | - Konstantinos C. Makris
- Cyprus International Institute for Environmental and Public Health, School of Health Sciences, Cyprus University of Technology, Limassol, Cyprus
| | - Alberto Caban-Martinez
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Romaina Iqbal
- Department of Community Health Sciences, Aga Khan University, Pakistan
| | - Faruk Ahmed
- Department of Engineering Technology, The University of Memphis, Memphis, Tennessee, USA
| | - Lota Creencia
- College of Fisheries and Aquatic Sciences, Western Philippines University, Palawan, Philippines
| | - Mohammad Shamsudduha
- Institute for Risk and Disaster Reduction, University College London, London, UK
| | - Fawaz Mzayek
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
| | - Chunrong Jia
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
| | - Hongmei Zhang
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
| | - Anwar Musah
- Department of Geography, University College London, London, UK
| | - Lora E. Fleming
- European Centre for Environment and Human Health, University of Exeter Medical School, Truro, Cornwall, UK
| | - Xichen Mou
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
| | - Csaba P. Kovesdy
- Division of Nephrology, University of Tennessee Health Science Centre, Memphis, Tenessee; USA
| | - Matthew O. Gribble
- Department of Medicine, Division of Occupational, Environmental, and Climate Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Abu Mohd Naser
- Division of Epidemiology, Biostatistics, and Environmental Health; School of Public Health, The University of Memphis, Memphis, Tennessee, USA
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Orysiak J, Młynarczyk M, Tomaszewski P. Fluid intake at work in foresters working in different thermal conditions. Sci Rep 2023; 13:15870. [PMID: 37741879 PMCID: PMC10518000 DOI: 10.1038/s41598-023-41652-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/29/2023] [Indexed: 09/25/2023] Open
Abstract
The primary aim of this study was to assess the impact of fluid intake on hydration status indices in men at work. The secondary aim was to determine the type of fluids drunk at work in different thermal conditions. Fifty-nine male foresters were examined before and after one working day during summer, autumn, and winter. Before and after work, urine and blood samples were obtained from foresters. Immediately after a shift, participants completed a questionnaire regarding fluid intake during one working day. The amount of fluid consumed affects the hydration urine indices. Urine specific gravity and urine osmolality significantly decreased with increasing fluid intake (r = - 0.385 and r = - 0.405, respectively). Moreover, an impact of season on the type of fluids consumed by workers was observed. Tea was significantly more often chosen by workers to drink in winter (68%) than in summer (32%) (p = 0.026). The consumption of any non-alcoholic fluids contributes to the daily total water intake, but it is necessary to create individualized fluid replacement plans. Workers should know how much and what types of drinks to consume at work.
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Affiliation(s)
- J Orysiak
- Department of Ergonomics, Central Institute for Labour Protection-National Research Institute, Czerniakowska St. 16, 00-701, Warsaw, Poland.
| | - M Młynarczyk
- Department of Ergonomics, Central Institute for Labour Protection-National Research Institute, Czerniakowska St. 16, 00-701, Warsaw, Poland
| | - P Tomaszewski
- Department of Tourism and Recreation, Józef Piłsudski University of Physical Education, Marymoncka St. 34, 00-968, Warsaw, Poland
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Krintus M, Panteghini M. Judging the clinical suitability of analytical performance of cardiac troponin assays. Clin Chem Lab Med 2023; 61:801-810. [PMID: 36798043 DOI: 10.1515/cclm-2023-0027] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 02/07/2023] [Indexed: 02/18/2023]
Abstract
New millennium diagnostic criteria for acute myocardial infarction precipitated a revolutionary shift from an approach based primarily on electrocardiography and clinical symptoms to a strategy based on biomarkers, and preferably cardiac troponins (cTn) I and T. In the last 20 years, clinical recommendations have strengthened the role of cTn and led to the development of highly sensitive (hs-cTn) assays, which are now leading players in all current clinical practice guidelines. To optimize the clinical use of these hs-cTn assays, focus on their analytical aspects has become increasingly important, emphasizing the need for the establishment of suitable analytical performance by the definition and implementation of appropriate specifications. An accurate estimate of measurement uncertainty, together with the acquisition of the highest analytical quality when very low concentrations of hs-cTn are measured, are essential requirements and should represent a practical laboratory standard in assuring optimal clinical use. Additional goals for further improving the quality of laboratory information should be the establishment of robust data concerning biological variation of cTn and the resolution of practical challenges opposed to the harmonization of cTn I results obtained by differing commercial measuring systems.
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Affiliation(s)
- Magdalena Krintus
- Department of Laboratory Medicine, Collegium Medicum, Nicolaus Copernicus University, Bydgoszcz, Torun, Poland
| | - Mauro Panteghini
- Department of Biomedical and Clinical Sciences, University of Milan, Milano, Italy
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4
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Szoke D, Robbiano C, Dolcini R, Montefusco L, Aiello GB, Caruso S, Ottolenghi A, Birindelli S, Panteghini M. Incidence and status of insulin secretion in pregnant women with flat plasma glucose profiles during oral glucose tolerance test. Clin Biochem 2022; 109-110:23-27. [PMID: 36041500 DOI: 10.1016/j.clinbiochem.2022.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/30/2022] [Accepted: 08/25/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Flat shaped glucose curves (FC) during oral glucose tolerance test (OGTT) in pregnant women (PW) are a not uncommon finding. We aimed to define the FC incidence in a large PW cohort and to describe the status of insulin and C-peptide secretion in women with FC when compared with a well-matched control group. METHODS 1050 PW performing OGTT for gestational diabetes screening were enrolled. An increase <6 % in plasma glucose (PG) during OGTT defined a FC. Serum samples for measuring insulin and C-peptide were also obtained. RESULTS 61 (5.8 %) women showed a FC. 60 of them, paired to a group of 60 no-FC women matched for age, body mass index and gestational age, were further investigated. C-peptide and insulin concentrations were significantly lower (P < 0.001) in FC in both 1-h and 2-h OGTT samples. When incremental area under the curves (AUC) normalized to PG were estimated, only AUCinsulin remained however significantly lower. The insulin sensitivity index was higher in FC. CONCLUSIONS PW with FC showed a hypersensitivity to insulin with normal β-cell function. Moreover, a delayed glucose absorption could be hypothesised because of the slight but continuously increasing shape of insulin curve found in FC group. Both phenomena could occur in parallel and contribute to FC.
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Affiliation(s)
- Dominika Szoke
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy.
| | | | - Roberta Dolcini
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Laura Montefusco
- UOC Endocrinologia e Diabetologia, ASST Fatebenefratelli-Sacco, Milano, Italy
| | | | - Simone Caruso
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Anna Ottolenghi
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Sarah Birindelli
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy
| | - Mauro Panteghini
- UOC Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy; Dipartimento di Scienze Biomediche e Cliniche "Luigi Sacco", Università degli Studi, Milano, Italy
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Zhang N, Zhang J, Wang X, Li Y, Yan Y, Ma G. Behaviors of Water Intake, Hydration Status, and Related Hydration Biomarkers among Physically Active Male Young Adults in Beijing, China: A Cross-Sectional Study. Int J Clin Pract 2022; 2022:9436186. [PMID: 36320894 PMCID: PMC9592216 DOI: 10.1155/2022/9436186] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/26/2022] [Accepted: 09/29/2022] [Indexed: 11/26/2022] Open
Abstract
Studies on the water intake of athletes in daily life are insufficient. The objective was to determine the water intake and hydration status among physically active male young adults. In this cross-sectional studies study, 111 physically active male young adults were recruited. The amount of daily total drinking fluid intake (TDF) among participants was recorded and evaluated in real time over 7 days using the "7-day 24-hour fluid intake questionnaire" (liq. In 7). The daily water intake from food (WFF) was calculated using the weighing, duplicate portion, and direct-drying method over 3 days. All urine samples over 3 days were collected, and urine biomarkers were determined. According to 24 h urine osmolality, the participants were divided into three groups with euhydration status, middle hydration, and hypo hydration statuses. Finally, 109 participants completed the study. The median daily total water intake (TWI), TDF, and WFF were 2701, ik1789, and 955 mL, respectively. Among participants, 17 participants (16%) were in euhydration status, 47 participants (43%) were in hypohydration, and 45 participants (41%) were in middle hydration. There were statistical significances in the 24 h urine volume, osmolality, urine specific gravity, and concentrations of K, Na, and Cl in different hydration statuses (χ 2 = 28.212, P < 0.01; χ 2 = 91.341, P < 0.01; χ 2 = 47.721, P < 0.01; χ 2 = 41.548, P < 0.01; χ 2 = 46.863, P < 0.01; and χ 2 = 40.839, P < 0.01). Moderate-intensity correlations were found between the TDF and 24 h urine volume, 24 h urine osmolality, 24 h urine Na concentration, morning urine osmolality, and morning urine Na concentration (r = 0.408, P < 0.01; r = -0.378, P < 0.01; r = -0.325, P < 0.01; r = -0.344, P < 0.01; and r = -0.329, P < 0.01). There were also moderate-intensity correlations between the TDF and 24 h urine osmolality, morning urine osmolality, and morning urine Na concentration (r = -0.365, P < 0.01; r = -0.371, P < 0.01; and r = -0.322, P = 0.01). Increased and higher moderate-intensity correlations were found between plain water and 24 h urine volume, 24 h urine osmolality, 24 h urine K and Na concentration, morning urine osmolality, and morning urine Na concentration (r = 0.374, P < 0.01; r = -0.520, P < 0.01; r = -0.312,P < 0.01; r = -0.355, P < 0.01; r = -0.446, P < 0.01; and r = -0.378, P < 0.01). Insufficient water intake and hypohydration were common among physically active male young adults. The amount and type of water intake were correlated with hydration status and urine biomarkers. The results could provide scientific and accurate references for the development of recommendations on water intake for athletes.
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Affiliation(s)
- Na Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Jianfen Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Xing Wang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Yibin Li
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
| | - Yi Yan
- College of Sports and Human Sciences, Beijing Sport University, 48 XinXi Road, Hai Dian District, Beijing 100084, China
| | - Guansheng Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
- Laboratory of Toxicological Research and Risk Assessment for Food Safety, Peking University, 38 Xue Yuan Road, Hai Dian District, Beijing 100191, China
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Rodin D, Shapiro Y, Pinhasov A, Kreinin A, Kirby M. An accurate wearable hydration sensor: Real-world evaluation of practical use. PLoS One 2022; 17:e0272646. [PMID: 36001536 PMCID: PMC9401113 DOI: 10.1371/journal.pone.0272646] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/22/2022] [Indexed: 11/18/2022] Open
Abstract
A wearable body hydration sensor employing photoplethysmographic and galvanic biosensors was field evaluated using 240 human participants with equal numbers of men and women volunteers. Monitoring of water mass loss due to perspiration was performed by medical balance measurements following one of two different treadmill physical exercise regimens over 90 minutes in 15-minute intervals with intervening 10-minute rest periods. Participants wore two different models of the dehydration body monitor device mated to commercially-available smartwatches (Samsung Gear S2 and Samsung Gear Fit2). Device output was recorded by Bluetooth wireless link to a standard smartphone in 20-second blocks. Comparison of the devices with the standard measurement method (change in body mass measured by medical balance) indicated very close agreement between changes in body water mass and device output (percent normalized mean root square error averaged approximately 2% for all participants). Bland-Altman analyses of method agreement indicated that <5% of participant values fell outside of the 95% confidence interval limits of agreement and all measured value differences were normally distributed around the line of equality. The results of this first-ever field trial of a practical, wearable hydration monitor suggests that this device will be a reliable tool to aid in geriatric hydration monitoring and physical training scenarios.
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Affiliation(s)
- Dmitry Rodin
- Institute for Personalized and Translational Medicine, Ariel University, Ariel, Israel
| | - Yair Shapiro
- Department of Health Administration and Adelson School of Medicine, Ariel University, Ariel, Israel
| | - Albert Pinhasov
- Department of Molecular Biology and Adelson School of Medicine, Ariel University, Ariel, Israel
| | - Anatoly Kreinin
- Department of Molecular Biology and Adelson School of Medicine, Ariel University, Ariel, Israel
| | - Michael Kirby
- Department of Molecular Biology and Adelson School of Medicine, Ariel University, Ariel, Israel
- * E-mail:
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Bender BF, Johnson NJ, Berry JA, Frazier KM, Bender MB. Automated Urinal-Based Specific Gravity Measurement Device for Real-Time Hydration Monitoring in Male Athletes. Front Sports Act Living 2022; 4:921418. [PMID: 35784803 PMCID: PMC9243503 DOI: 10.3389/fspor.2022.921418] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 05/24/2022] [Indexed: 11/19/2022] Open
Abstract
Acute and chronic hydration status is important for athlete safety and performance and is frequently measured by sports scientists and performance staff in team environments via urinalysis. However, the time required for urine collection, staff testing, and reporting often delays immediate reporting and personalized nutrition insight in situations of acute hydration management before training or competition. Furthermore, the burdensome urine collection and testing process often renders chronic hydration monitoring sporadic or non-existent in real-world settings. An automated urinalysis device (InFlow) was developed to measure specific gravity, an index of hydration status, in real-time during urination. The device was strongly correlated to optical refractometry with a mean absolute error of 0.0029 (±0.0021). Our results show this device provides a novel and useful approach for real-time hydration status via urinalysis for male athletes in team environments with high testing frequency demands.
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8
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Biological variation of arginine vasopressin. Eur J Appl Physiol 2020; 120:635-642. [DOI: 10.1007/s00421-020-04303-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/10/2020] [Indexed: 12/30/2022]
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Bunn DK, Hooper L. Signs and Symptoms of Low-Intake Dehydration Do Not Work in Older Care Home Residents-DRIE Diagnostic Accuracy Study. J Am Med Dir Assoc 2019; 20:963-970. [PMID: 30872081 DOI: 10.1016/j.jamda.2019.01.122] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 01/04/2019] [Accepted: 01/05/2019] [Indexed: 12/30/2022]
Abstract
OBJECTIVES To assess the diagnostic accuracy of commonly used signs and symptoms of low-intake dehydration in older care home residents. DESIGN Prospective diagnostic accuracy study. SETTING 56 care homes offering residential, nursing, and/or dementia care to older adults in Norfolk and Suffolk, United Kingdom. PARTICIPANTS 188 consecutively recruited care home residents aged ≥65 years, without cardiac or renal failure and not receiving palliative care. Overall, 66% were female, the mean age was 85.7 years (standard deviation 7.8), and the median Mini-Mental State Examination MMSE score was 23 (interquartile range 18-26). INDEX TESTS Over 2 hours, participants underwent double-blind assessment of 49 signs and symptoms of dehydration and measurement of serum osmolality from a venous blood sample. Signs and symptoms included skin turgor; mouth, skin, and axillary dryness; capillary refill; sunken eyes; blood pressure on resting and after standing; body temperature; pulse rate; and self-reported feelings of thirst and well-being. REFERENCE STANDARD Serum osmolality, with current dehydration defined as >300 mOsm/kg, and impending dehydration ≥295 mOsm/kg. OUTCOME MEASURES For dichotomous tests, we aimed for sensitivity and specificity >70%, and for continuous tests, an area under the curve in receiver operating characteristic plots of >0.7. RESULTS Although 20% of residents had current low-intake dehydration and a further 28% impending dehydration, none of the commonly used clinical signs and symptoms usefully discriminated between participants with or without low-intake dehydration at either cut-off. CONCLUSIONS/IMPLICATIONS This study consolidates evidence that commonly used signs and symptoms of dehydration lack even basic levels of diagnostic accuracy in older adults, implying that many who are dehydrated are not being identified, thus compromising their health and well-being. We suggest that these tests be withdrawn from practice and replaced with a 2-stage screening process that includes serum osmolarity, calculated from sodium, potassium, urea, and glucose levels (assessed routinely using the Khajuria and Krahn equation), followed by serum osmolality measurement for those identified as high risk (calculated serum osmolarity >295 mmol/L).
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Affiliation(s)
- Diane K Bunn
- School of Health Sciences, Norwich Research Park, University of East Anglia, Norwich, Norfolk, England, United Kingdom.
| | - Lee Hooper
- Norwich Medical School, Norwich Research Park, University of East Anglia, Norwich, Norfolk, England, United Kingdom
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10
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Armstrong LE, Johnson EC. Water Intake, Water Balance, and the Elusive Daily Water Requirement. Nutrients 2018; 10:E1928. [PMID: 30563134 PMCID: PMC6315424 DOI: 10.3390/nu10121928] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 11/11/2018] [Accepted: 11/27/2018] [Indexed: 12/12/2022] Open
Abstract
Water is essential for metabolism, substrate transport across membranes, cellular homeostasis, temperature regulation, and circulatory function. Although nutritional and physiological research teams and professional organizations have described the daily total water intakes (TWI, L/24h) and Adequate Intakes (AI) of children, women, and men, there is no widespread consensus regarding the human water requirements of different demographic groups. These requirements remain undefined because of the dynamic complexity inherent in the human water regulatory network, which involves the central nervous system and several organ systems, as well as large inter-individual differences. The present review analyzes published evidence that is relevant to these issues and presents a novel approach to assessing the daily water requirements of individuals in all sex and life-stage groups, as an alternative to AI values based on survey data. This empirical method focuses on the intensity of a specific neuroendocrine response (e.g., plasma arginine vasopressin (AVP) concentration) employed by the brain to regulate total body water volume and concentration. We consider this autonomically-controlled neuroendocrine response to be an inherent hydration biomarker and one means by which the brain maintains good health and optimal function. We also propose that this individualized method defines the elusive state of euhydration (i.e., water balance) and distinguishes it from hypohydration. Using plasma AVP concentration to analyze multiple published data sets that included both men and women, we determined that a mild neuroendocrine defense of body water commences when TWI is ˂1.8 L/24h, that 19⁻71% of adults in various countries consume less than this TWI each day, and consuming less than the 24-h water AI may influence the risk of dysfunctional metabolism and chronic diseases.
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Affiliation(s)
- Lawrence E Armstrong
- University of Connecticut, Human Performance Laboratory and Department of Nutritional Sciences, Storrs CT 06269-1110, USA.
| | - Evan C Johnson
- University of Wyoming, Human Integrated Physiology Laboratory, Division of Kinesiology and Health, Laramie, WY 82071, USA.
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11
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Sollanek KJ, Kenefick RW, Cheuvront SN. Importance of sample volume to the measurement and interpretation of plasma osmolality. J Clin Lab Anal 2018; 33:e22727. [PMID: 30474168 PMCID: PMC6818608 DOI: 10.1002/jcla.22727] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 11/12/2022] Open
Abstract
Background Small sample volumes may artificially elevate plasma osmolality (Posm) measured by freezing point depression. The purpose of this study was to compare two widely different sample volumes of measured Posm (mmol/kg) to each other, and to calculated osmolarity (mmol/L), across a physiological Posm range (~50 mmol/kg). Methods Posm was measured using freezing point depression and osmolarity calculated from measures of sodium, glucose, and blood urea nitrogen. The influence of sample volume was investigated by comparing 20 and 250 μL Posm samples (n = 126 pairs). Thirty‐two volunteers were tested multiple times while EUH (n = 115) or DEH (n = 11) by −4.0% body mass. Protinol™ (240, 280, and 320 mmol/kg) and Clinitrol™ (290 mmol/kg) reference solutions were compared similarly (n = 282 pairs). Results The 20 μL samples of plasma showed a 7 mmol/kg positive bias compared to 250 μL samples and displayed a nearly constant proportional error across the range tested (slope = 0.929). Calculated osmolarity was lower than 20 μL Posm by the same negative bias (−6.9 mmol/kg) but not different from 250 μL Posm (0.1 mmol/kg). The differences between 20 and 250 μL samples of Protinol™ were significantly higher than Clinitrol™. Conclusions These results demonstrate that Posm measured by freezing point depression will be ~7 mmol/kg higher when using 20 μL vs 250 μL sample volumes. Approximately half of this effect may be due to plasma proteins. Posm sample volume should be carefully considered when calculating the osmole gap or assessing hydration status.
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Affiliation(s)
- Kurt J Sollanek
- Department of Kinesiology, Sonoma State University, Rohnert Park, California
| | - Robert W Kenefick
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Samuel N Cheuvront
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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12
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Brescon C, Pegaz PY, Godet P, Malgoyre A, Charlot K. Effect of Urinary Sheath Use on Hydration Status of Fighter Pilots Under Severe Thermal Stress: An Observational Study. Mil Med 2018; 184:e217-e222. [DOI: 10.1093/milmed/usy233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/12/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Caroline Brescon
- Forces Françaises aux Emirats Arabes Unis, Centre Médical des Armées, Base Aérienne d’Al Dhafra, United Arab Emirates
| | - Pierre-Yves Pegaz
- Forces Françaises aux Emirats Arabes Unis, Centre Médical des Armées, Base Aérienne d’Al Dhafra, United Arab Emirates
| | - Patrick Godet
- Forces Françaises aux Emirats Arabes Unis, Base Aérienne d’Al Dhafra, United Arab Emirates
| | - Alexandra Malgoyre
- Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Keyne Charlot
- Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, Département Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
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Boraczyński T, Boraczyński M, Podstawski R, Borysławski K, Jankowski K. BODY MASS LOSS IN DRY SAUNA AND HEART RATE RESPONSE TO HEAT STRESS. REV BRAS MED ESPORTE 2018. [DOI: 10.1590/1517-869220182404172175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT Objectives: The aim of the study was to determine the effects of sauna-induced heat exposure on body mass loss (BML) and its relationships with basic anthropometric and physiological variables. Methods: The sample comprised 230 healthy adult males aged 21.0 ± 1.08 years (age range: 20.0–24.5 years). Body surface area (BSA) was determined and two groups of individuals with high BSA (BSAH; n = 58) and low BSA (BSAL; n = 74) were extracted. The intervention consisted of two 10-min dry sauna sessions separated by a 5-min interlude. Pre-, peri-, and post-sauna measures of nude body mass (BM) and heart rate (HR) were taken. Results: BML differed between BSA groups by 0.28 kg (74.81%). Absolute and relative BML most strongly correlated with BM and BSA (p < 0.001). Among the four considered height–weight indexes, the Quetelet I Index and Body Mass Index showed the strongest associations (p < 0.001) with BML whereas the weakest were with the Rohrer Index (p < 0.01) and Slenderness Index (p < 0.05). Compared with BML, differences in HR were relatively minor (from 9.90% to 18.07%) and a significant association was observed between BML and HR at rest (p < 0.01) and in 10th and 20th min of sauna bathing (p < 0.001). Conclusions: The magnitude of BML in healthy adult males after passive heat exposure was dependent on BM and concomitantly BSA. The physiological cost of dry sauna-induced thermal strain (as assessed by BML and HR) is greater in individuals with high BM and BSA. BM and HR monitoring is also recommended in order to minimize the risk of homeostatic imbalance and cardiovascular events and this cohort should more frequently cool the body and consume a greater volume of fluids during sauna bathing. Evidence Level II; Prospective comparative study.
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Zhang N, Du S, Tang Z, Zheng M, Yan R, Zhu Y, Ma G. Hydration, Fluid Intake, and Related Urine Biomarkers among Male College Students in Cangzhou, China: A Cross-Sectional Study-Applications for Assessing Fluid Intake and Adequate Water Intake. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:E513. [PMID: 28492493 PMCID: PMC5451964 DOI: 10.3390/ijerph14050513] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 05/03/2017] [Accepted: 05/05/2017] [Indexed: 11/16/2022]
Abstract
The objectives of this study were to assess the associations between fluid intake and urine biomarkers and to determine daily total fluid intake for assessing hydration status for male college students. A total of 68 male college students aged 18-25 years recruited from Cangzhou, China completed a 7-day cross-sectional study. From day 1 to day 7; all subjects were asked to complete a self-administered 7-day 24-h fluid intake record. The foods eaten by subjects were weighed and 24-h urine was collected for three consecutive days on the last three consecutive days. On the sixth day, urine osmolality, specific gravity (USG), pH, and concentrations of potassium, sodium, and chloride was determined. Subjects were divided into optimal hydration, middle hydration, and hypohydration groups according to their 24-h urine osmolality. Strong relationships were found between daily total fluid intake and 24-h urine biomarkers, especially for 24-h urine volume (r = 0.76; p < 0.0001) and osmolality (r = 0.76; p < 0.0001). The percentage of the variances in daily total fluid intake (R²) explained by PLS (partial least squares) model with seven urinary biomarkers was 68.9%; two urine biomarkers-24-h urine volume and osmolality-were identified as possible key predictors. The daily total fluid intake for assessing optimal hydration was 2582 mL, while the daily total fluid intake for assessing hypohydration was 2502 mL. Differences in fluid intake and urine biomarkers were found among male college students with different hydration status. A strong relationship existed between urine biomarkers and fluid intake. A PLS model identified that key variables for assessing daily total fluid intake were 24-h urine volume and osmolality. It was feasibility to use total fluid intake to judge hydration status.
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Affiliation(s)
- Na Zhang
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Haidian District, Beijing 100191, China.
- Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, School of Public Health, Peking University, 38 Xue Yuan Road, Haidian District, Beijing 100191, China.
| | - Songming Du
- Chinese Nutrition Society, 6 Guang An Men Nei Street, Xicheng District, Beijing 100053, China.
| | - Zhenchuang Tang
- Institute of Food and Nutrition Development, Ministry of Agriculture, 12 Zhong Guan Cun Nan Street, Haidian District, Beijing 100181, China.
| | - Mengqi Zheng
- National Institute for Nutrition and Health, Chinese Center for Disease Control and Prevention, 29 Nan Wei Road, Xicheng District, Beijing 100050, China.
| | - Ruixia Yan
- Department of Health Management and Service, Cangzhou Medical College, Higher Education District, Cangzhou 061000, China.
| | - Yitang Zhu
- Clinical Laboratory, Cangzhou Central Hospital, Xinhua District, Cangzhou 061000, China.
| | - Guansheng Ma
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, 38 Xue Yuan Road, Haidian District, Beijing 100191, China.
- Beijing Key Laboratory of Toxicological Research and Risk Assessment for Food Safety, School of Public Health, Peking University, 38 Xue Yuan Road, Haidian District, Beijing 100191, China.
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Walker A, Pope R, Orr RM. The impact of fire suppression tasks on firefighter hydration: a critical review with consideration of the utility of reported hydration measures. Ann Occup Environ Med 2016; 28:63. [PMID: 27891237 PMCID: PMC5111227 DOI: 10.1186/s40557-016-0152-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 11/07/2016] [Indexed: 11/13/2022] Open
Abstract
Background Firefighting is a highly stressful occupation with unique physical challenges, apparel and environments that increase the potential for dehydration. Dehydration leaves the firefighter at risk of harm to their health, safety and performance. The purpose of this review was to critically analyse the current literature investigating the impact of fighting ‘live’ fires on firefighter hydration. Methods A systematic search was performed of four electronic databases for relevant published studies investigating the impact of live fire suppression on firefighter hydration. Study eligibility was assessed using strict inclusion and exclusion criteria. The included studies were critically appraised using the Downs and Black protocol and graded according to the Kennelly grading system. Results Ten studies met the eligibility criteria for this review. The average score for methodological quality was 55 %, ranging from 50 % (‘fair’ quality) to 61 % (‘good’ quality) with a ‘substantial agreement’ between raters (k = .772). Wildfire suppression was considered in five studies and structural fire suppression in five studies. Results varied across the studies, reflecting variations in outcome measures, hydration protocols and interventions. Three studies reported significant indicators of dehydration resulting from structural fire suppression, while two studies found mixed results, with some measures indicating dehydration and other measures an unchanged hydration status. Three studies found non-significant changes in hydration resulting from wildfire firefighting and two studies found significant improvements in markers of hydration. Ad libitum fluid intake was a common factor across the studies finding no, or less severe, dehydration. Conclusions The evidence confirms that structural and wildfire firefighting can cause dehydration. Ad libitum drinking may be sufficient to maintain hydration in many wildfire environments but possibly not during intense, longer duration, hot structural fire operations. Future high quality research better quantifying the effects of these influences on the degree of dehydration is required to inform policies and procedures that ensure firefighter health and safety.
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Affiliation(s)
- Adam Walker
- Faculty of Health Sciences and Medicine, Bond Institute of Health and Sport, Bond University, Gold Coast, QLD 4226 Australia
| | - Rodney Pope
- Tactical Research Unit, Bond University, Gold Coast, QLD 4226 Australia
| | - Robin Marc Orr
- Tactical Research Unit, Bond University, Gold Coast, QLD 4226 Australia
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Malisova O, Athanasatou A, Pepa A, Husemann M, Domnik K, Braun H, Mora-Rodriguez R, Ortega JF, Fernandez-Elias VE, Kapsokefalou M. Water Intake and Hydration Indices in Healthy European Adults: The European Hydration Research Study (EHRS). Nutrients 2016; 8:204. [PMID: 27058557 PMCID: PMC4848673 DOI: 10.3390/nu8040204] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/15/2016] [Accepted: 03/30/2016] [Indexed: 11/30/2022] Open
Abstract
Hydration status is linked with health, wellness, and performance. We evaluated hydration status, water intake, and urine output for seven consecutive days in healthy adults. Volunteers living in Spain, Germany, or Greece (n = 573, 39 ± 12 years (51.1% males), 25.0 ± 4.6 kg/m2 BMI) participated in an eight-day study protocol. Total water intake was estimated from seven-day food and drink diaries. Hydration status was measured in urine samples collected over 24 h for seven days and in blood samples collected in fasting state on the mornings of days 1 and 8. Total daily water intake was 2.75 ± 1.01 L, water from beverages 2.10 ± 0.91 L, water from foods 0.66 ± 0.29 L. Urine parameters were: 24 h volume 1.65 ± 0.70 L, 24 h osmolality 631 ± 221 mOsmol/kg Η2Ο, 24 h specific gravity 1.017 ± 0.005, 24 h excretion of sodium 166.9 ± 54.7 mEq, 24 h excretion of potassium 72.4 ± 24.6 mEq, color chart 4.2 ± 1.4. Predictors for urine osmolality were age, country, gender, and BMI. Blood indices were: haemoglobin concentration 14.7 ± 1.7 g/dL, hematocrit 43% ± 4% and serum osmolality 294 ± 9 mOsmol/kg Η2Ο. Daily water intake was higher in summer (2.8 ± 1.02 L) than in winter (2.6 ± 0.98 L) (p = 0.019). Water intake was associated negatively with urine specific gravity, urine color, and urine sodium and potassium concentrations (p < 0.01). Applying urine osmolality cut-offs, approximately 60% of participants were euhydrated and 20% hyperhydrated or dehydrated. Most participants were euhydrated, but a substantial number of people (40%) deviated from a normal hydration level.
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Affiliation(s)
- Olga Malisova
- Unit of Human Nutrition, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos Str., Athens 11855, Greece.
| | - Adelais Athanasatou
- Unit of Human Nutrition, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos Str., Athens 11855, Greece.
| | - Alex Pepa
- Unit of Human Nutrition, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos Str., Athens 11855, Greece.
| | - Marlien Husemann
- Institute of Biochemistry, German Sport University, Cologne 50993, Germany.
| | - Kirsten Domnik
- Institute of Biochemistry, German Sport University, Cologne 50993, Germany.
| | - Hans Braun
- Institute of Biochemistry, German Sport University, Cologne 50993, Germany.
| | - Ricardo Mora-Rodriguez
- Exercise Physiology Lab at Toledo, University of Castilla-la Mancha, Toledo 13071, Spain.
| | - Juan F Ortega
- Exercise Physiology Lab at Toledo, University of Castilla-la Mancha, Toledo 13071, Spain.
| | | | - Maria Kapsokefalou
- Unit of Human Nutrition, Department of Food Science and Human Nutrition, Agricultural University of Athens, 75 Iera Odos Str., Athens 11855, Greece.
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Heavens KR, Charkoudian N, O'Brien C, Kenefick RW, Cheuvront SN. Noninvasive assessment of extracellular and intracellular dehydration in healthy humans using the resistance-reactance-score graph method. Am J Clin Nutr 2016; 103:724-9. [PMID: 26843158 DOI: 10.3945/ajcn.115.115352] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 12/14/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Few dehydration assessment measures provide accurate information; most are based on reference change values and very few are diagnostically accurate from a single observation or measure. Bioelectrical impedance may lack the precision to detect common forms of dehydration in healthy individuals. Limitations in bioimpedance may be addressed by a unique resistance-reactance (RXc)-score graph method, which transforms vector components into z scores for use with any impedance analyzer in any population. OBJECTIVE We tested whether the RXc-score graph method provides accurate single or serial assessments of dehydration when compared with gold-standard measures of total body water by using stable isotope dilution (deuterium oxide) combined with body-weight changes. DESIGN We retrospectively analyzed data from a previous study in which 9 healthy young men participated in 3 trials: euhydration (EUH), extracellular dehydration (ED; via a diuretic), and intracellular dehydration (ID; via exercise in the heat). RESULTS Participants lost 4-5% of their body weight during the dehydration trials; volume loss was similar between trials (ID compared with ED group: 3.5 ± 0.8 compared with 3.0 ± 0.6 L; P > 0.05). Despite significant losses of body water, most RXc vector scores for ED and ID groups were classified as "normal" (within the 75% population tolerance ellipse). However, directional displacement of vectors was consistent with loss of volume in both ED and ID conditions compared with the EUH condition and tended to be longer in ED than in ID conditions (P = 0.054). CONCLUSIONS We conclude that, whereas individual RXc-score graph values do not provide accurate detection of dehydration from single measurements, directional changes in vector values from serial measurements are consistent with fluid loss for both ED and ID conditions. The RXc-score graph method may therefore alert clinicians to changes in hydration state, which may bolster the interpretation of other recognized change measures of hydration.
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Twenty-four-hour urine osmolality as a physiological index of adequate water intake. DISEASE MARKERS 2015; 2015:231063. [PMID: 25866433 PMCID: PMC4381985 DOI: 10.1155/2015/231063] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 03/06/2015] [Indexed: 12/05/2022]
Abstract
While associations exist between water, hydration, and disease risk, research quantifying the dose-response effect of water on health is limited. Thus, the water intake necessary to maintain optimal hydration from a physiological and health standpoint remains unclear. The aim of this analysis was to derive a 24 h urine osmolality (UOsm) threshold that would provide an index of “optimal hydration,” sufficient to compensate water losses and also be biologically significant relative to the risk of disease. Ninety-five adults (31.5 ± 4.3 years, 23.2 ± 2.7 kg·m−2) collected 24 h urine, provided morning blood samples, and completed food and fluid intake diaries over 3 consecutive weekdays. A UOsm threshold was derived using 3 approaches, taking into account European dietary reference values for water; total fluid intake, and urine volumes associated with reduced risk for lithiasis and chronic kidney disease and plasma vasopressin concentration. The aggregate of these approaches suggest that a 24 h urine osmolality ≤500 mOsm·kg−1 may be a simple indicator of optimal hydration, representing a total daily fluid intake adequate to compensate for daily losses, ensure urinary output sufficient to reduce the risk of urolithiasis and renal function decline, and avoid elevated plasma vasopressin concentrations mediating the increased antidiuretic effort.
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Raines J, Snow R, Nichols D, Aisbett B. Fluid intake, hydration, work physiology of wildfire fighters working in the heat over consecutive days. ACTA ACUST UNITED AC 2015; 59:554-65. [PMID: 25667157 DOI: 10.1093/annhyg/meu113] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Accepted: 12/02/2014] [Indexed: 11/13/2022]
Abstract
PURPOSE (i) To evaluate firefighters' pre- and post-shift hydration status across two shifts of wildfire suppression work in hot weather conditions. (ii) To document firefighters' fluid intake during and between two shifts of wildfire suppression work. (iii) To compare firefighters' heart rate, activity, rating of perceived exertion (RPE), and core temperature across the two consecutive shifts of wildfire suppression work. METHOD Across two consecutive days, 12 salaried firefighters' hydration status was measured immediately pre- and post-shift. Hydration status was also measured 2h post-shift. RPE was also measured immediately post-shift on each day. Work activity, heart rate, and core temperature were logged continuously during each shift. Ten firefighters also manually recorded their food and fluid intake before, during, and after both fireground shifts. RESULTS Firefighters were not euhydrated at all measurement points on Day one (292±1 mOsm l(-1)) and euhydrated across these same time points on Day two (289±0.5 mOsm l(-1)). Fluid consumption following firefighters' shift on Day one (1792±1134ml) trended (P = 0.08) higher than Day two (1108±1142ml). Daily total fluid intake was not different (P = 0.27), averaging 6443±1941ml across both days. Core temperature and the time spent ≥ 70%HRmax were both elevated on Day one (when firefighters were not euhydrated). Firefighters' work activity profile was not different between both days of work. CONCLUSION There was no difference in firefighters' pre- to post-shift hydration within each shift, suggesting ad libitum drinking was at least sufficient to maintain pre-shift hydration status, even in hot conditions. Firefighters' relative hypohydration on Day one (despite a slightly lower ambient temperature) may have been associated with elevations in core temperature, more time in the higher heart rate zones, and 'post-shift' RPE.
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Affiliation(s)
- Jenni Raines
- 1.Centre for Physical Activity and Nutrition Research, Australia Research, Deakin University, Burwood 3125, Australia 2.Bushfire Co-Operative Research Centre, East Melbourne 3002, Australia
| | - Rodney Snow
- 1.Centre for Physical Activity and Nutrition Research, Australia Research, Deakin University, Burwood 3125, Australia
| | - David Nichols
- 2.Bushfire Co-Operative Research Centre, East Melbourne 3002, Australia 3.Research and Innovation, Country Fire Authority, Burwood 3151, Australia
| | - Brad Aisbett
- 1.Centre for Physical Activity and Nutrition Research, Australia Research, Deakin University, Burwood 3125, Australia 2.Bushfire Co-Operative Research Centre, East Melbourne 3002, Australia
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Cheuvront SN, Kenefick RW. Dehydration: physiology, assessment, and performance effects. Compr Physiol 2014; 4:257-85. [PMID: 24692140 DOI: 10.1002/cphy.c130017] [Citation(s) in RCA: 272] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This article provides a comprehensive review of dehydration assessment and presents a unique evaluation of the dehydration and performance literature. The importance of osmolality and volume are emphasized when discussing the physiology, assessment, and performance effects of dehydration. The underappreciated physiologic distinction between a loss of hypo-osmotic body water (intracellular dehydration) and an iso-osmotic loss of body water (extracellular dehydration) is presented and argued as the single most essential aspect of dehydration assessment. The importance of diagnostic and biological variation analyses to dehydration assessment methods is reviewed and their use in gauging the true potential of any dehydration assessment method highlighted. The necessity for establishing proper baselines is discussed, as is the magnitude of dehydration required to elicit reliable and detectable osmotic or volume-mediated compensatory physiologic responses. The discussion of physiologic responses further helps inform and explain our analysis of the literature suggesting a ≥ 2% dehydration threshold for impaired endurance exercise performance mediated by volume loss. In contrast, no clear threshold or plausible mechanism(s) support the marginal, but potentially important, impairment in strength, and power observed with dehydration. Similarly, the potential for dehydration to impair cognition appears small and related primarily to distraction or discomfort. The impact of dehydration on any particular sport skill or task is therefore likely dependent upon the makeup of the task itself (e.g., endurance, strength, cognitive, and motor skill).
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Affiliation(s)
- Samuel N Cheuvront
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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Reference change values to assess changes in concentrations of biomarkers of exposure in individuals participating in a cigarette-switching study. ACTA ACUST UNITED AC 2013; 52:399-411. [DOI: 10.1515/cclm-2013-0581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 09/05/2013] [Indexed: 11/15/2022]
Abstract
Abstract
Background: In a previous clinical study, levels of biomarkers of exposure (BoEs) for specific toxicants were significantly reduced in smokers who switched from conventional cigarettes to reduced toxicant prototype (RTP) cigarettes. Very little is known about the biological variability of tobacco smoke BoEs within individuals and sub-groups, and the descriptive group-comparison statistics might not be sufficient to understand such changes. Therefore, we assessed how different statistical methods could be used to interpret changes in urine BoE levels at the individual level.
Methods: We used non-parametric statistical reference limits, the empirical rule and reference change values (RCVs) to assess changes in levels of BoEs related to four toxicants in cigarettes smoke. Current smokers [of 6 mg and 1 mg International Organization for Standardization (ISO) tar yields] were allocated to switching to RTP groups or non-switching control groups within their respective tar bands. There were two 6 mg tar study groups, with a non-switching group (CC6, n=46) and a group switching to an RTP containing tobacco-substitute sheet and modified filter (TSS6, n=49); and three 1 mg tar smoker groups, with one non-switching (CC1, n=42), a group switching to an RTP containing tobacco-substitute sheet and modified filter (TSS1, n=44) and one switching to an RTP containing an enzyme-treated tobacco and modified filter (BT1, n=47).
Results: Assessment of the direction of change showed that up to the 100% of subjects experienced a decrease in levels of some BoEs. Between 49% and 64% of subjects in the switching groups were classified as having decreased levels of 3-hydroxy-1-methylpropylmercapturic acid (HMPMA) by the non-parametric criterion, whereas only 2%–6% had reduced levels of N-nitrosoanatabine (NAT). Of non-switchers, in 7%–14% of those smoking 1 mg ISO tar yield cigarettes increases were classified across all BoEs. RCVs highlighted patterns with more detail, showing that most changes occurred within 14 days of switching. Among smokers who switched to 6 mg RTPs, 40%, 44%, 6% and 15%, respectively, were classified as experiencing significant decreasing levels of HPMA, 3-hydroxypropylmercapturic acid, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol and NAT, whereas in the two 1 mg switching groups 46%, 22%, 11% and 52% and 43%, 27%, 2% and 16% had decreased levels of the same biomarkers. Up to five subjects in the 6 mg non-switching group were classified as having increased levels of all BoEs.
Conclusions: Although we believe that is not possible to determine whether the observed changes in BoEs reflect biological relevance, the use of reference values enables assessment of changes in BoEs at the individual level. Estimates of the BoE variability between subjects might aid study design and setting minimum targets for smoke toxicant yields for future development of RTPs.
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Abstract
OBJECTIVE To examine the relationships between changes in static prestage and poststage measures of commonly used hematological and urinary markers of hydration status and body mass (BM) in participants in a 3-day trail run. DESIGN Descriptive field study. SETTING Three Cranes Challenge trail run, South Africa. PARTICIPANTS Twenty (6 men and 14 women) amateur runners. INTERVENTIONS In stage 1 (S1), 29.3 km and 37.9 km in stage 2 (S2), and 27.8 km in stage 3 (S3). MAIN OUTCOME MEASURES Prestage and poststage individual changes in serum osmolality (S osm), serum sodium (s[Na]), plasma volume (PV), urine osmolality (U osm), urine specific gravity (U sg), and BM. RESULTS Consistently, mild environmental conditions were experienced on the 3 days of the race (ambient temperature range, 11.5-22.8°C). Mean S osm increased by 5 ± 6, 7 ± 9, and 3 ± 4 mOsm/kg during S1, S2, and S3, respectively, and returned to baseline pre-S2 and pre-S3. The correlation between individual prestage and poststage changes in S osm, Uosm, and U sg (n = 60) were nonsignificant (P > 0.05; r = 0.0047, r = 0.0074). There was a significant, but relatively low correlation between changes in S osm and percentage reduction in BM (r = 0.35; P < 0.01) and prechange and postchange in s[Na] (r = 0.45; P < 0.001). CONCLUSIONS Serum osmality values confirm appropriate interstage rehydration. Changes in U osm, U sg, BM, s[Na+], and PV are not closely related to changes in S osm as markers of hydration assessment in multiday events in which single static measures of hydration status are required. These measures of hydration station status are therefore not recommended in this field setting.
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Kafri MW, Myint PK, Doherty D, Wilson AH, Potter JF, Hooper L. The diagnostic accuracy of multi-frequency bioelectrical impedance analysis in diagnosing dehydration after stroke. Med Sci Monit 2013; 19:548-70. [PMID: 23839255 PMCID: PMC3711909 DOI: 10.12659/msm.883972] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Background Non-invasive methods for detecting water-loss dehydration following acute stroke would be clinically useful. We evaluated the diagnostic accuracy of multi-frequency bioelectrical impedance analysis (MF-BIA) against reference standards serum osmolality and osmolarity. Material/Methods Patients admitted to an acute stroke unit were recruited. Blood samples for electrolytes and osmolality were taken within 20 minutes of MF-BIA. Total body water (TBW%), intracellular (ICW%) and extracellular water (ECW%), as percentages of total body weight, were calculated by MF-BIA equipment and from impedance measures using published equations for older people. These were compared to hydration status (based on serum osmolality and calculated osmolarity). The most promising Receiver Operating Characteristics curves were plotted. Results 27 stroke patients were recruited (mean age 71.3, SD10.7). Only a TBW% cut-off at 46% was consistent with current dehydration (serum osmolality >300 mOsm/kg) and TBW% at 47% impending dehydration (calculated osmolarity ≥295–300 mOsm/L) with sensitivity and specificity both >60%. Even here diagnostic accuracy of MF-BIA was poor, a third of those with dehydration were wrongly classified as hydrated and a third classified as dehydrated were well hydrated. Secondary analyses assessing diagnostic accuracy of TBW% for men and women separately, and using TBW as a percentage of lean body mass showed some promise, but did not provide diagnostically accurate measures across the population. Conclusions MF-BIA appears ineffective at diagnosing water-loss dehydration after stroke and cannot be recommended as a test for dehydration, but separating assessment by sex, and using TBW as a percentage of lean body weight may warrant further investigation.
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Affiliation(s)
- Mohannad W Kafri
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK.
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Perrier E, Rondeau P, Poupin M, Le Bellego L, Armstrong LE, Lang F, Stookey J, Tack I, Vergne S, Klein A. Relation between urinary hydration biomarkers and total fluid intake in healthy adults. Eur J Clin Nutr 2013; 67:939-43. [PMID: 23695204 PMCID: PMC3778844 DOI: 10.1038/ejcn.2013.93] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 04/03/2013] [Accepted: 04/04/2013] [Indexed: 11/09/2022]
Abstract
BACKGROUND/OBJECTIVES In sedentary adults, hydration is mostly influenced by total fluid intake and not by sweat losses; moreover, low daily fluid intake is associated with adverse health outcomes. This study aimed to model the relation between total fluid intake and urinary hydration biomarkers. SUBJECTS/METHODS During 4 consecutive weekdays, 82 adults (age, 31.6±4.3 years; body mass index, 23.2±2.7 kg/m(2); 52% female) recorded food and fluid consumed, collected one first morning urine (FMU) void and three 24-h (24hU) samples. The strength of linear association between urinary hydration biomarkers and fluid intake volume was evaluated using simple linear regression and Pearson's correlation. Multivariate partial least squares (PLS) modeled the association between fluid intake and 24hU hydration biomarkers. RESULTS Strong associations (|r| ≥ 0.6; P<0.001) were found between total fluid intake volume and 24hU osmolality, color, specific gravity (USG), volume and solute concentrations. Many 24hU biomarkers were collinear (osmolality versus color: r=0.49-0.76; USG versus color: r=0.46-0.78; osmolality versus USG: 0.86-0.97; P<0.001). Measures in FMU were not strongly correlated to intake. Multivariate PLS and simple linear regression using urine volume explained >50% of the variance in fluid intake volume (r(2)=0.59 and 0.52, respectively); however the error in both models was high and the limits of agreement very large. CONCLUSIONS Hydration biomarkers in 24hU are strongly correlated with daily total fluid intake volume in sedentary adults in free-living conditions; however, the margin of error in the present models limits the applicability of estimating fluid intake from urinary biomarkers.
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Perrier E, Demazières A, Girard N, Pross N, Osbild D, Metzger D, Guelinckx I, Klein A. Circadian variation and responsiveness of hydration biomarkers to changes in daily water intake. Eur J Appl Physiol 2013; 113:2143-51. [PMID: 23604869 PMCID: PMC3714557 DOI: 10.1007/s00421-013-2649-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 04/15/2013] [Indexed: 11/25/2022]
Abstract
Biomarkers of hydration change in response to acute dehydration; however, their responsiveness to changes in fluid intake volume, without exercise or heat exposure, has not been adequately described. Moreover, patterns of circadian variation in hydration biomarkers have not been established. The study aims were to (1) assess the response of hydration biomarkers to changes in daily water intake; and (2) evaluate circadian variation in urinary and salivary biomarkers. Fifty-two adults (24.8 ± 3.1 years; 22.3 ± 1.6 kg/m2; 79 % female), grouped based on habitual fluid intake (low drinkers, n = 30, <1.2 L/day; high drinkers, n = 22, >2.0 L/day), completed a 5-day inpatient crossover trial. On days 1 and 2, low drinkers received 1.0 L/day of water while high drinkers received 2.5 L/day. On days 3 through 5, intake was reversed between groups. Plasma and saliva osmolality were assessed daily at predetermined times, and all urine produced over 24 h was collected in timed intervals. ANOVA with intake (1.0 vs. 2.5 L/day), day, and time revealed that (1) urine concentration (osmolality, specific gravity, color) and volume, but not plasma nor saliva osmolality, responded to changes in water intake; (2) urinary hydration biomarkers and saliva osmolality vary as a function of the time of day; and (3) urine osmolality measured in samples collected during the afternoon most closely reflects the corresponding 24 h value. Overall, urinary hydration biomarkers are responsive to changes in water intake, and stabilize within 24 h of modifying intake volume. Moreover, short afternoon urine collections may be able to replace 24 h collections for more convenience in hydration assessment.
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Cheuvront SN, Kenefick RW, Charkoudian N, Sawka MN. Physiologic basis for understanding quantitative dehydration assessment. Am J Clin Nutr 2013; 97:455-62. [PMID: 23343973 DOI: 10.3945/ajcn.112.044172] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dehydration (body water deficit) is a physiologic state that can have profound implications for human health and performance. Unfortunately, dehydration can be difficult to assess, and there is no single, universal gold standard for decision making. In this article, we review the physiologic basis for understanding quantitative dehydration assessment. We highlight how phenomenologic interpretations of dehydration depend critically on the type (dehydration compared with volume depletion) and magnitude (moderate compared with severe) of dehydration, which in turn influence the osmotic (plasma osmolality) and blood volume-dependent compensatory thresholds for antidiuretic and thirst responses. In particular, we review new findings regarding the biological variation in osmotic responses to dehydration and discuss how this variation can help provide a quantitative and clinically relevant link between the physiology and phenomenology of dehydration. Practical measures with empirical thresholds are provided as a starting point for improving the practice of dehydration assessment.
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Armstrong LE. Challenges of linking chronic dehydration and fluid consumption to health outcomes. Nutr Rev 2013; 70 Suppl 2:S121-7. [PMID: 23121346 DOI: 10.1111/j.1753-4887.2012.00539.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The purpose of this article is to review the effects of chronic mild dehydration and fluid consumption on specific health outcomes including obesity. The electronic databases PubMed and Google Scholar were searched for relevant literature published from the time of their inception to 2011, with results restricted to studies performed on human subjects and reports in the English language. Key words included the following: dehydration, hypohydration, water intake, fluid intake, disease, and the names of specific disease states. Strength of evidence categories were described for 1) medical conditions associated with chronic dehydration or low daily water intake, and 2) randomized-controlled trials regarding the effects of increased water consumption on caloric intake, weight gain, and satiety. This process determined that urolithiasis is the only disorder that has been consistently associated (i.e., 11 of 13 publications) with chronic low daily water intake. Regarding obesity and type 2 diabetes, evidence suggests that increased water intake may reduce caloric intake for some individuals. Recommendations for future investigations include measuring total fluid intake (water + beverages + water in solid food), conducting randomized-controlled experiments, identifying novel hydration biomarkers, and delineating hydration categories.
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Affiliation(s)
- Lawrence E Armstrong
- Department of Kinesiology, University of Connecticut, Human Performance Laboratory, Storrs, Connecticut 06269-1110, USA
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Cheuvront SN, Kenefick RW, Sollanek KJ, Ely BR, Sawka MN. Water-deficit equation: systematic analysis and improvement. Am J Clin Nutr 2013; 97:79-85. [PMID: 23235197 DOI: 10.3945/ajcn.112.046839] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The water-deficit equation {WD(1) = 0.6 × B(m) × [1 - (140 ÷ Na(+))]; B(m) denotes body mass} is used in medicine and nutrition to estimate the volume (L) of water required to correct dehydration during the initial stages of fluid-replacement therapy. Several equation assumptions may limit its accuracy, but none have been systematically tested. OBJECTIVES We quantified the potential error in WD(1) for the estimation of free water (FW) and total body water (TBW) losses and systematically evaluated its assumptions. DESIGN Thirty-six euhydrated volunteers were dehydrated (2.2-5.8% B(m)) via thermoregulatory sweating. Assumptions within WD(1) were tested by substituting measured euhydrated values for assumed or unknown values. These included the known (premorbid) B(m) (WD(2)), a proposed correction for unknown B(m) (WD(3)), the TBW estimated from body composition (WD(4)), the actual plasma sodium (WD(5)), the substitution of plasma osmolality (Posm) for sodium (WD(6)), and actual Posm (WD(7)). RESULTS Dehydration reduced TBW by 3.49 ± 0.91 L, 57% of which (2.02 ± 0.96 L) was FW loss, and increased plasma sodium from 139 (range: 135-143 mmol/L) to 143 (range: 141-148 mmol/L) mmol/L. Calculations for WD(1) through WD(7) all underestimated TBW loss by 1.5-2.5 L (P < 0.05). WD(1) through WD(5) underestimated FW by 0.5 L to 1.0 L (P < 0.05), but WD(6) and WD(7) estimated FW loss to within 0.06-0.16 L (P > 0.05). CONCLUSIONS WD(1) grossly underestimates TBW and FW losses. Corrections for unknowns and assumptions (WD(2) through WD(5)) improved estimates little. The use of WD(6) = 0.6 × B(m) × [1 - (290 ÷ Posm)] accurately estimates FW but still underestimates TBW losses by >40%.
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Affiliation(s)
- Samuel N Cheuvront
- US Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA.
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Lippi G, Plebani M. False myths and legends in laboratory diagnostics. Clin Chem Lab Med 2013; 51:2087-97. [DOI: 10.1515/cclm-2013-0105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 02/26/2013] [Indexed: 11/15/2022]
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Abstract
As the clinical laboratory attempts to manage and mitigate risk, individual patient results can be a useful complement to routine quality-control materials. Patient results can be used to detect error or identify potential testing complications at all phases of the total testing process. Patient-specific data algorithms include delta checks, tests to verify specimen or tube type, absurdity checks, and result-based reporting. Delta checks are highlighted because they can uniquely point to issues all along the testing cycle, from preanalytical to postanalytical concerns. When used properly, patient results can work to minimize risk and increase the quality of individual patient results.
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Affiliation(s)
- Joely A Straseski
- ARUP Laboratories, University of Utah, 500 Chipeta Way, Mail Code 115, Salt Lake City, UT 84108-1221, USA.
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Abstract
Little is known about the impact of habitual fluid intake on physiology. Specifically, biomarkers of hydration status and body water regulation have not been adequately explored in adults who consume different fluid volumes in everyday conditions, without prolonged exercise or environmental exposure. The purpose of the present study was to compare adults with habitually different fluid intakes with respect to biomarkers implicated in the assessment of hydration status, the regulation of total body water and the risk of kidney pathologies. In the present cross-sectional study, seventy-one adults (thirty-two men, thirty-nine women, age 25–40 years) were classified according to daily fluid intake: thirty-nine low drinkers (LD; ≤ 1·2 litres/d) and thirty-two high drinkers (HD; 2–4 litres/d). During four consecutive days, urinary parameters (first morning urine (FMU) on day 1 and subsequent 24 h urine (24hU) collections), blood parameters, and food and beverage intake were assessed. ANOVA and non-parametric comparisons revealed significant differences between the LD and HD groups in 24hU volume (1·0 (se 0·1) v. 2·4 (se 0·1) litres), specific gravity (median 1·023 v. 1·010), osmolality (767 (se 27) v. 371 (se 33) mOsm/kg) and colour (3·1 (se 0·2) v. 1·8 (se 0·2)). Similarly, in the FMU, the LD group produced a smaller amount of more concentrated urine. Plasma cortisol, creatinine and arginine vasopressin concentrations were significantly higher among the LD. Plasma osmolality was similar between the groups, suggesting physiological adaptations to preserve plasma osmolality despite low fluid intake. The long-term impact of adaptations to preserve plasma osmolality must be examined, particularly in the context of renal health.
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Fraser CG. Reference change values. Clin Chem Lab Med 2012; 50:807-12. [DOI: 10.1515/cclm.2011.733] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 09/08/2011] [Indexed: 11/15/2022]
Abstract
AbstractReference change values (RCV) provide objective tools for assessment of the significance of differences in serial results from an individual. The concept is simple and the calculation easy, since all laboratories know their analytical imprecision (CV
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Cheuvront SN, Ely BR, Kenefick RW, Buller MJ, Charkoudian N, Sawka MN. Hydration assessment using the cardiovascular response to standing. Eur J Appl Physiol 2012; 112:4081-9. [PMID: 22481637 DOI: 10.1007/s00421-012-2390-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 03/16/2012] [Indexed: 01/04/2023]
Abstract
The cardiovascular response to standing (sit-to-stand change in heart rate; SSΔHR) is commonly employed as a screening tool to detect hypohydration (body water deficit). No study has systematically evaluated SSΔHR cut points using different magnitudes or different types of controlled hypohydration. The objective of this study was to determine the diagnostic accuracy of the often proposed 20 b/min SSΔHR cut point using both hypertonic and isotonic models of hypohydration. Thirteen healthy young adults (8M, 5F) underwent three bouts of controlled hypohydration. The first bout used sweating to elicit large losses of body water (mass) (>3 % sweat). The second two bouts were matched to elicit 3 % body mass losses (3 % diuretic; 3 % sweat). A euhydration control trial (EUH) was paired with each hypohydration trial for a total of six trials. Heart rate was assessed after 3-min sitting and after 1-min standing during all trials. SSΔHR was compared among trials, and receiver operator characteristic curve analysis was used to determine diagnostic accuracy of the 20 b/min SSΔHR cut point. Volunteers lost 4.5 ± 1.1, 3.0 ± 0.6, and 3.2 ± 0.6 % body mass during >3 % sweat, 3 % diuretic, and 3 % sweat trials, respectively. SSΔHR (b/min) was 9 ± 8 (EUH), 20 ± 12 (>3 % sweat; P < 0.05 vs. EUH), 17 ± 7 (3 % diuretic; P < 0.05 vs. EUH), and 13 ± 11 (3 % sweat). The 20 beats/min cut point had high specificity (90 %) but low sensitivity (44 %) and overall diagnostic accuracy of 67 %. SSΔHR increased significantly in response to severe hypertonic hypohydration and moderate isotonic hypohydration, but not moderate hypertonic hypohydration. However, the 20 beats/min cut point afforded only marginal diagnostic accuracy.
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Affiliation(s)
- Samuel N Cheuvront
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760-5007, USA.
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Sollanek KJ, Kenefick RW, Walsh NP, Fortes MB, Esmaeelpour M, Cheuvront SN. Assessment of thermal dehydration using the human eye: What is the potential? J Therm Biol 2012. [DOI: 10.1016/j.jtherbio.2011.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Affiliation(s)
- Callum G Fraser
- Centre for Research into Cancer Prevention and Screening, University of Dundee, Dundee, Scotland
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Affiliation(s)
- Callum G Fraser
- Centre for Research into Cancer Prevention and Screening, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland
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