The Experts below are selected from a list of 3435 Experts worldwide ranked by ideXlab platform
Stavros A Kavouras - One of the best experts on this subject based on the ideXlab platform.
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Urine Color as an indicator of Urine concentration in pregnant and lactating women
European Journal of Nutrition, 2017Co-Authors: Amy L Mckenzie, Erica T Perrier, Stavros A Kavouras, Alexis Klein, Colleen X Munoz, Lindsay A Ellis, Isabelle Guelinckx, Lawrence E ArmstrongAbstract:Aim Urine concentration measured via osmolality (UOSM) and specific gravity (USG) reflects the adequacy of daily fluid intake, which has important relationships to health in pregnant (PREG) and lactating (LACT) women. Urine Color (UCOL) may be a practical, surrogate marker for whole-body hydration status.
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validation of a Urine Color scale for assessment of Urine osmolality in healthy children
European Journal of Nutrition, 2016Co-Authors: Stavros A Kavouras, Erica T Perrier, Evan C Johnson, Dimitris Bougatsas, Giannis Arnaoutis, Demosthenes B Panagiotakos, Alexis KleinAbstract:Aim Urine Color (UC) is a practical tool for hydration assessment. The technique has been validated in adults, but has not been tested in children.
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24 h void number as an indicator of hydration status
European Journal of Clinical Nutrition, 2015Co-Authors: Jenna M Burchfield, Stavros A Kavouras, J D Adams, Matthew S Ganio, M A Gonzalez, Christian B Ridings, Nicole E Moyen, Matthew A TuckerAbstract:Few user-friendly hydration assessment techniques exist for the general population to use on a daily basis. The present study evaluated void number over 24 h as a potential hydration assessment tool. Male and female subjects collected Urine for 24 h while adequately hydrated (n=44; 22±4 years, 168±16 cm, 73±15 kg) or fluid restricted (n=43; 22±3 years, 175±10 cm, 81±24 kg). As a control, participants were asked to void when feeling the ‘first urge to void’ on a commonly used urge scale and noted the volume of each void. For each sample, 24-h Urine volume, osmolality (UOSM), specific gravity (USG) and Color were measured in the laboratory. As designed, the level of urge upon voiding was consistent throughout the study (2±0; ‘first urge to void’). Samples were classified by USG as either euhydrated (USG<1.020) or hypohydrated (USG⩾1.020). Grouping by UOSM did not change results. Euhydrated versus hypohydrated individuals had greater 24-h Urine volume (1933±864 versus 967±306 ml, respectively) and lower Urine Color (2±1 versus 5±1), USG (1.012±0.004 versus 1.025±0.004) and UOSM (457±180 versus 874±175 mOsm/kg H2O; all P<0.001). Euhydrated individuals voided more than hypohydrated individuals over the 24-h period (5±2 versus 3±1 voids; P<0.001). Additionally, void number inversely correlated with hydration status as identified by USG (r=−0.50; P<0.05) and UOSM (r=−0.56; P<0.05). In conclusion, over 24 h, individuals with a higher void number were euhydrated (that is, had less concentrated hydration biomarkers) than those with a lower void number. Based on these data, void number might be utilized as a simple and feasible hydration assessment for the general public, as it utilizes no equipment or technical expertise.
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ad libitum fluid intake does not prevent dehydration in suboptimally hydrated young soccer players during a training session of a summer camp
International Journal of Sport Nutrition and Exercise Metabolism, 2013Co-Authors: Giannis Arnaoutis, Stavros A Kavouras, Yiannis P Kotsis, Yiannis E Tsekouras, Michalis Makrillos, Costas N BardisAbstract:There is a lack of studies concerning hydration status of young athletes exercising in the heat. Purpose: To assess preexercise hydration status in young soccer players during a summer sports camp and to evaluate bodywater balance after soccer training sessions. Methods: Initial hydration status was assessed in 107 young male soccer players (age 11–16 yr) during the 2nd day of the camp. Seventy-two athletes agreed to be monitored during 2 more training sessions (3rd and 5th days of the camp) to calculate dehydration via changes in body weight, while water drinking was allowed ad libitum. Hydration status was assessed via Urine specific gravity (USG), Urine Color, and changes in total body weight. Mean environmental temperature and humidity were 27.2 ± 2 °C and 57% ± 9%, respectively. Results: According to USG values, 95 of 107 of the players were hypohydrated (USG ≥ 1.020) before practice. The prevalence of dehydration observed was maintained on both days, with 95.8% and 97.2% of the players being dehydrated after the training sessions on the 3rd and 5th days, respectively. Despite fluid availability, 54 of the 66 (81.8%) dehydrated players reduced their body weight (–0.35 ± 0.04 kg) as a response to training, while 74.6% (47 out of the 63) further reduced their body weight (–0.22 ± 0.03 kg) after training on the 5th day. Conclusion: Approximately 90% of the young soccer players who began exercising under warm weather conditions were hypohydrated, while drinking ad libitum during practice did not prevent further dehydration in already dehydrated players.
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educational intervention on water intake improves hydration status and enhances exercise performance in athletic youth
Scandinavian Journal of Medicine & Science in Sports, 2012Co-Authors: Stavros A Kavouras, Giannis Arnaoutis, M Makrillos, C Garagouni, E Nikolaou, O Chira, E Ellinikaki, Labros S SidossisAbstract:We aimed to evaluate whether an intervention program emphasizing in increased fluid intake can improve exercise performance in children exercising in the heat. Ninety-two young athletes participated in the study (age: 13.8 ± 0.4 years, weight: 54.9 ± 1.5 kg). Thirty-one (boys: 13, girls: 18) children served as the control group (CON) and 61 (boys: 30, girls: 31) as the intervention (INT). Volunteers had free access to fluids. Hydration was assessed on the basis of first morning Urine. A series of field tests were used to evaluate exercise performance. All tests occurred outdoors in the morning (mean ambient temperature=28 °C). After baseline testing, INT attended a lecture on hydration, and Urine Color charts were mounted in all bathrooms. Additionally, water accessibility was facilitated in training, dining and resting areas. Hydration status was improved significantly in the INT [USG: pre=1.031 ± 0.09, post=1.023 ± 0.012, P 0.05; Urine osmolality (mOsm/kg water) 970 ± 38 vs 961 ± 38, P>0.05]. Performance in an endurance run was improved significantly only in INT (time for 600 m: pre=189 ± 5 s, post=167 ± 4 s, P<0.05). Improving hydration status by ad libitum consumption of water can enhance performance in young children exercising in the heat.
Erica T Perrier - One of the best experts on this subject based on the ideXlab platform.
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combining Urine Color and void number to assess hydration in adults and children
European Journal of Clinical Nutrition, 2021Co-Authors: J D Adams, Erica T Perrier, Evan C Johnson, Dimitris Bougatsas, Giannis Arnaoutis, Demosthenes B Panagiotakos, Lisa T Jansen, Catalina Capitanjimenez, Andy Mauromoustakos, Isabelle GuelinckxAbstract:BACKGROUND/OBJECTIVES To test the diagnostic ability of two combined practical markers for elevated Urine osmolality (underhydration) in free-living adults and children. SUBJECTS/METHODS One hundred and one healthy adults (females n = 52, 40 ± 14 y, 1.70 ± 0.95 m, 76.7 ± 17.4 kg, 26.5 ± 5.5 kg/m2) and 210 children (females = 105, 1.49 ± 0.13 m, 43.4 ± 12.6 kg, 19.2 ± 3.2 kg m-2) collected Urine for 24-h. Urine was analyzed for Urine osmolality (UOsm), Color (UC), while the number of voids (void) was also recorded. Receiver Operating Characteristic (ROC) analysis was performed for UC, void, and combination of UC and void, to determine markers' diagnostic ability for detecting underhydration based on elevated UOsm (UOsm ≥ 800 mmol kg-1). RESULTS Linear regression analysis revealed that UC was significantly associated with UOsm in both adults (R2 = 0.38; P 3 and void 3 and void <5 had an overall diagnostic ability for underhydration of 89% with sensitivity and specificity of 100% and 62%, respectively. CONCLUSIONS Urine Color alone and the combination of Urine Color with void number can a valid and simple field-measure to detect underhydration based on elevated Urine osmolality.
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criterion values for Urine specific gravity and Urine Color representing adequate water intake in healthy adults
European Journal of Clinical Nutrition, 2017Co-Authors: Erica T Perrier, Jeanne H Bottin, Mariacristina Vecchio, Guillaume LemetaisAbstract:Growing evidence suggests a distinction between water intake necessary for maintaining a euhydrated state, and water intake considered to be adequate from a perspective of long-term health. Previously, we have proposed that maintaining a 24-h Urine osmolality (UOsm) of ⩽500 mOsm/kg is a desirable target for Urine concentration to ensure sufficient urinary output to reduce renal health risk and circulating vasopressin. In clinical practice and field monitoring, the measurement of UOsm is not practical. In this analysis, we calculate criterion values for Urine-specific gravity (USG) and Urine Color (UCol), two measures which have broad applicability in clinical and field settings. A receiver operating characteristic curve analysis performed on 817 Urine samples demonstrates that a USG ⩾1.013 detects UOsm>500 mOsm/kg with very high accuracy (AUC 0.984), whereas a subject-assessed UCol⩾4 offers high sensitivity and moderate specificity (AUC 0.831) for detecting UOsm >500 m Osm/kg.
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Urine Color as an indicator of Urine concentration in pregnant and lactating women
European Journal of Nutrition, 2017Co-Authors: Amy L Mckenzie, Erica T Perrier, Stavros A Kavouras, Alexis Klein, Colleen X Munoz, Lindsay A Ellis, Isabelle Guelinckx, Lawrence E ArmstrongAbstract:Aim Urine concentration measured via osmolality (UOSM) and specific gravity (USG) reflects the adequacy of daily fluid intake, which has important relationships to health in pregnant (PREG) and lactating (LACT) women. Urine Color (UCOL) may be a practical, surrogate marker for whole-body hydration status.
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assessing a tool for self monitoring hydration using Urine Color in pregnant and breastfeeding women a cross sectional online survey
Annals of Nutrition and Metabolism, 2017Co-Authors: Marion Rigaud, Erica T Perrier, Camila Sevalho Corcao, Sabine BoesenmarianiAbstract:Background: Pregnant and breastfeeding women experience great changes in their total body water content and water dynamics. To support the accretion of total body water during pregnancy and compensate for the water lost through breast milk during breastfeeding, increased adequate intakes (AI) for total water have been established by various health authorities. Despite this widespread advice, several studies suggest that pregnant and breastfeeding women do not meet the AI for total water, suggesting the need to raise women's awareness on the importance of adequate water intake, particularly during pregnancy and breastfeeding, as well as to provide them with a simple means of monitoring their hydration on a day-to-day basis. A Urine Color (UC) scale recently has been validated for hydration monitoring in pregnant and breastfeeding women. Summary: We sought to develop a version of a tool based on the UC scale, using only images or illustrations, which could be understood by users of various nationalities and spoken languages. Pregnant and breastfeeding women ( n = 1,275) from Brazil, Mexico, and Poland were shown 3 versions of the tool. Understanding, appreciation, simplicity and intent to use were evaluated using a questionnaire consisting of 26 items. Key Messages: Among the 3 versions tested, one tool emerged as the most highly understood (88% spontaneous understanding) and was highly appreciated by users (mean [SD]: 8.40 [2.20] out of 10). There were no differences between countries. Furthermore, 83% reported being very likely to use the tool daily. These results suggest that a simple tool based on the UC scale will help pregnant and breastfeeding women meet the AI for total water.
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validation of a Urine Color scale for assessment of Urine osmolality in healthy children
European Journal of Nutrition, 2016Co-Authors: Stavros A Kavouras, Erica T Perrier, Evan C Johnson, Dimitris Bougatsas, Giannis Arnaoutis, Demosthenes B Panagiotakos, Alexis KleinAbstract:Aim Urine Color (UC) is a practical tool for hydration assessment. The technique has been validated in adults, but has not been tested in children.
A A Megahed - One of the best experts on this subject based on the ideXlab platform.
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clinical utility of Urine specific gravity electrical conductivity and Color as on farm methods for evaluating Urine concentration in dairy cattle
Journal of Veterinary Internal Medicine, 2019Co-Authors: Walter Grunberg, A A Megahed, Peter D ConstableAbstract:BACKGROUND: Urine concentration (UC) provides clinically useful information concerning hydration status and renal function of animals. OBJECTIVES: To characterize the clinical performance of Urine specific gravity measured by optical refractometry (USG-R ) or Multistix-SG Urine reagent dipstick (USG-D ), Urine electrical conductivity using an OAKTON Con 6 conductivity handheld meter (UEC ), Urine Color (UColor ) using a custom-designed 8-point Color chart, and Urine creatinine concentration (UCreat ) for assessing UC in dairy cattle. ANIMALS: 20 periparturient Holstein-Friesian cows. METHODS: Urine was obtained by perineal stimulation or urethral catheterization and Urine osmolality (UOsm , reference method), USG-R , USG-D , UEC , UColor , and UCreat determined. Diagnostic test performance was evaluated using Spearman's rho and logistic regression to determine the area under the receiver operating curve (AUC) and optimal cut point for diagnosing hypohydration (UOsm ≥800 mOsm/kg). P < .05 was considered significant. RESULTS: The best performing test for diagnosing hypohydration was USG-R (AUC = 0.90) at an optimal cut point ≥1.030. The second-best performing test was UEC (AUC = 0.82) at a cut point of ≥23.7 mS/cm, followed by UCreat (AUC = 0.76) at a cut point of ≥95.3 mg/dL, and UColor (AUC = 0.74) at a cut point of ≥4 on an 8-point scale. Urine specific gravity measured by dipstick performed poorly (AUC = 0.63). CONCLUSIONS AND CLINICAL IMPORTANCE: USG-R and UEC provide practical and sufficiently accurate methods for measuring UC in dairy cattle. Urine Color had moderate clinical utility as a no-cost cow-side method for assessing UC, whereas dipstick refractometry is not recommended for assessing UC.
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Clinical utility of Urine specific gravity, electrical conductivity, and Color as on-farm methods for evaluating Urine concentration in dairy cattle.
Journal of Veterinary Internal Medicine, 2019Co-Authors: A A Megahed, Walter Grunberg, Peter D ConstableAbstract:BACKGROUND: Urine concentration (UC) provides clinically useful information concerning hydration status and renal function of animals. OBJECTIVES: To characterize the clinical performance of Urine specific gravity measured by optical refractometry (USG-R ) or Multistix-SG Urine reagent dipstick (USG-D ), Urine electrical conductivity using an OAKTON Con 6 conductivity handheld meter (UEC ), Urine Color (UColor ) using a custom-designed 8-point Color chart, and Urine creatinine concentration (UCreat ) for assessing UC in dairy cattle. ANIMALS: 20 periparturient Holstein-Friesian cows. METHODS: Urine was obtained by perineal stimulation or urethral catheterization and Urine osmolality (UOsm , reference method), USG-R , USG-D , UEC , UColor , and UCreat determined. Diagnostic test performance was evaluated using Spearman's rho and logistic regression to determine the area under the receiver operating curve (AUC) and optimal cut point for diagnosing hypohydration (UOsm ≥800 mOsm/kg). P
Peter D Constable - One of the best experts on this subject based on the ideXlab platform.
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clinical utility of Urine specific gravity electrical conductivity and Color as on farm methods for evaluating Urine concentration in dairy cattle
Journal of Veterinary Internal Medicine, 2019Co-Authors: Walter Grunberg, A A Megahed, Peter D ConstableAbstract:BACKGROUND: Urine concentration (UC) provides clinically useful information concerning hydration status and renal function of animals. OBJECTIVES: To characterize the clinical performance of Urine specific gravity measured by optical refractometry (USG-R ) or Multistix-SG Urine reagent dipstick (USG-D ), Urine electrical conductivity using an OAKTON Con 6 conductivity handheld meter (UEC ), Urine Color (UColor ) using a custom-designed 8-point Color chart, and Urine creatinine concentration (UCreat ) for assessing UC in dairy cattle. ANIMALS: 20 periparturient Holstein-Friesian cows. METHODS: Urine was obtained by perineal stimulation or urethral catheterization and Urine osmolality (UOsm , reference method), USG-R , USG-D , UEC , UColor , and UCreat determined. Diagnostic test performance was evaluated using Spearman's rho and logistic regression to determine the area under the receiver operating curve (AUC) and optimal cut point for diagnosing hypohydration (UOsm ≥800 mOsm/kg). P < .05 was considered significant. RESULTS: The best performing test for diagnosing hypohydration was USG-R (AUC = 0.90) at an optimal cut point ≥1.030. The second-best performing test was UEC (AUC = 0.82) at a cut point of ≥23.7 mS/cm, followed by UCreat (AUC = 0.76) at a cut point of ≥95.3 mg/dL, and UColor (AUC = 0.74) at a cut point of ≥4 on an 8-point scale. Urine specific gravity measured by dipstick performed poorly (AUC = 0.63). CONCLUSIONS AND CLINICAL IMPORTANCE: USG-R and UEC provide practical and sufficiently accurate methods for measuring UC in dairy cattle. Urine Color had moderate clinical utility as a no-cost cow-side method for assessing UC, whereas dipstick refractometry is not recommended for assessing UC.
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Clinical utility of Urine specific gravity, electrical conductivity, and Color as on-farm methods for evaluating Urine concentration in dairy cattle.
Journal of Veterinary Internal Medicine, 2019Co-Authors: A A Megahed, Walter Grunberg, Peter D ConstableAbstract:BACKGROUND: Urine concentration (UC) provides clinically useful information concerning hydration status and renal function of animals. OBJECTIVES: To characterize the clinical performance of Urine specific gravity measured by optical refractometry (USG-R ) or Multistix-SG Urine reagent dipstick (USG-D ), Urine electrical conductivity using an OAKTON Con 6 conductivity handheld meter (UEC ), Urine Color (UColor ) using a custom-designed 8-point Color chart, and Urine creatinine concentration (UCreat ) for assessing UC in dairy cattle. ANIMALS: 20 periparturient Holstein-Friesian cows. METHODS: Urine was obtained by perineal stimulation or urethral catheterization and Urine osmolality (UOsm , reference method), USG-R , USG-D , UEC , UColor , and UCreat determined. Diagnostic test performance was evaluated using Spearman's rho and logistic regression to determine the area under the receiver operating curve (AUC) and optimal cut point for diagnosing hypohydration (UOsm ≥800 mOsm/kg). P
Lawrence E Armstrong - One of the best experts on this subject based on the ideXlab platform.
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Urine Color as an indicator of Urine concentration in pregnant and lactating women
European Journal of Nutrition, 2017Co-Authors: Amy L Mckenzie, Erica T Perrier, Stavros A Kavouras, Alexis Klein, Colleen X Munoz, Lindsay A Ellis, Isabelle Guelinckx, Lawrence E ArmstrongAbstract:Aim Urine concentration measured via osmolality (UOSM) and specific gravity (USG) reflects the adequacy of daily fluid intake, which has important relationships to health in pregnant (PREG) and lactating (LACT) women. Urine Color (UCOL) may be a practical, surrogate marker for whole-body hydration status.
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assessing hydration status the elusive gold standard
Journal of The American College of Nutrition, 2007Co-Authors: Lawrence E ArmstrongAbstract:Acknowledging that total body water (TBW) turnover is complex, and that no measurement is valid for all situations, this review evaluates 13 hydration assessment techniques. Although validated laboratory methods exist for TBW and extracellular volume, no evidence incontrovertibly demonstrates that any concentration measurement, including plasma osmolality (Posm), accurately represents TBW gain and loss during daily activities. Further, one blood or Urine sample cannot validly represent fluctuating TBW and fluid compartments. Future research should (a) evaluate novel techniques that assess hydration in real time and are precise, accurate, reliable, non-invasive, portable, inexpensive, safe, and simple; and (b) clarify the relationship between Posm and TBW oscillations in various scenarios. Key teaching points: All hydration assessment techniques provide singular measures of a complex and dynamic fluid matrix, containing interconnected compartments. A single gold standard, including plasma osmolality, is not possible for all hydration assessment requirements. In the laboratory, measurement resolution and accuracy are essential. Field assessment of hydration requires techniques that are easy-to-use, safe, portable, and inexpensive. Total body water approximates “euhydration” when morning body weight is near the normal baseline, fluid intake is adequate, Urine Color is pale yellow, and Urine volume is normal. Body weight change provides the simplest and most accurate index of hydration status in real time, when serial measurements are made in close proximity.
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Heat acclimatization and hydration status of American football players during initial summer workouts.
Journal of strength and conditioning research, 2006Co-Authors: Susan W. Yeargin, Douglas J Casa, Lawrence E Armstrong, Greig Watson, Daniel A. Judelson, Eleni Psathas, Sarah L. SparrowAbstract:This investigation evaluated the new National Collegiate Athletic Association model of heat acclimatization for football players using physiological, psychological, fluid balance, anthropometric, and nutritional variables. Eleven football players (20 +/- 1 year, 1.88 +/- 0.05 m, and 115.36 +/- 18.85 kg) from a Division I football team were observed for the first 8 days of preseason practices. Measurements such as heart rate and gastrointestinal temperature (T(GI)) via telemetric sensor were taken before, 3 times during, and after practice daily. An average 1.39-kg (1.2%) decrease of body mass occurred from prepractice to postpractice (p < 0.01). Consistent with mild body mass losses, urinary indices of hydration status (i.e., Color, specific gravity, and osmolality) indicated mild fluid deficits. A significant increase (p < 0.05) from pre- to postpractice was observed in Urine Color and Urine specific gravity, but chronic hypohydration over the 8 days was not noted. The Environmental Symptoms Questionnaire (ESQ) postpractice score was significantly higher (p < 0.05) than the prepractice score was, but averages did not differ across practice days. There was no difference in postpractice T(GI) measurements across days (p < 0.05). Heart rate, T(GI), and ESQ measurements indicated that football players experienced gradual heat acclimatization and enhanced heat tolerance, despite progressive increases of exercise variables, clothing, and environmental stressors.
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urinary indices during dehydration exercise and rehydration
International Journal of Sport Nutrition, 1998Co-Authors: Lawrence E Armstrong, Douglas J Casa, Jorge Herrera A Soto, Frank T Hacker, Stavros A Kavouras, Carl M MareshAbstract:This investigation evaluated the validity and sensitivity of Urine Color (Ucol), specific gravity (Usg), and osmolality (Uosm) as indices of hydration status, by comparing them to changes in body water. Nine highly trained males underwent a 42-hr protocol involving dehydration to 3.7% of body mass (Day 1, −2.64 kg), cycling to exhaustion (Day 2, −5.2% of body mass, −3.68 kg), and oral rehydration for 21 hr. The ranges of mean (across time) blood and Urine values were Ucol, 1-7; Usg, 1.004-1.029; U08m, 117-1,081 mOsm • kg−1; and plasma osmolality (Posm), 280-298 mOsm ⋅ kg−1. Urine Color tracked changes in body water as effectively as (or better than) Uosm, Usg, Urine volume, Posm, plasma sodium, and plasma total protein. We concluded that (a) Ucol, Uosm, and Usg are valid indices of hydration status, and (b) marked dehydration, exercise, and rehydration had little effect on the validity and sensitivity of these indices.
