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Effects of a 14-Day Hydration Intervention on Individuals with Habitually Low Fluid Intake.
Caldwell, AR, Rosa-Caldwell, ME, Keeter, C, Johnson, EC, Péronnet, F, Ganio, MS
Annals of nutrition & metabolism. 2020;:67-68
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Abstract
BACKGROUND Debate continues over whether or not individuals with low total water intake (TWI) are in a chronic fluid deficit (i.e., low total body water) [1]. When women with habitually low TWI (1.6 ± 0.5 L/day) increased their fluid intake (3.5 ± 0.1 L/day) for 4 days 24-h urine osmolality decreased, but there was no change in body weight, a proxy for total body water (TBW) [2]. In a small (n = 5) study of adult men, there were no observable changes in TBW, as measured by bioelectrical impedance, after increasing TWI for 4 weeks [3]. However, body weight increased and salivary osmolality decreased indicating that the study may have been underpowered to detect changes in TBW. Further, no studies to date have measured changes in blood volume (BV) when TWI is increased. OBJECTIVES Therefore, the purpose of this study was to identify individuals with habitually low fluid intake and determine if increasing TWI, for 14 days, resulted in changes in TBW or BV. METHODS In order to identify individuals with low TWI, 889 healthy adults were screened. Participants with a self-reported TWI less than 1.8 L/day (men) or 1.2 L/day (women), and a 24-h urine osmolality greater than 800 mOsm were included in the intervention phase of the study. For the intervention phase, 15 participants were assigned to the experimental group and 8 participants were assigned to the control group. The intervention period lasted for 14 days and consisted of 2 visits to our laboratory: one before the intervention (baseline) and 14 days into the intervention (14-day follow-up). At these visits, BV was measured using a CO-rebreathe procedure and deuterium oxide (D2O) was administered to measure TBW. Urine samples were collected immediately prior, and 3-8 h after the D2O dose to allow for equilibration. Prior to each visit, participants collected 24-h urine to measure 24-h hydration status. After the baseline visit, the experimental group increased their TWI to 3.7 L for males and 2.7 L for females in order to meet the current Institute of Medicine recommendations for TWI. RESULTS Twenty-four-hour urine osmolality decreased (-438.7 ± 362.1 mOsm; p < 0.001) and urine volume increased (1,526 ± 869 mL; p < 0.001) in the experimental group from baseline, while there were no differences in osmolality (-74.7 ± 572 mOsm; p = 0.45), or urine volume (-32 ± 1,376 mL; p = 0.89) in the control group. However, there were no changes in BV (Fig. 1a) or changes in TBW (Fig. 1b) in either group. CONCLUSIONS Increasing fluid intake in individuals with habitually low TWI increases 24-h urine volume and decreases urine osmolality but does not result in changes in TBW or BV. These findings are in agreement with previous work indicating that TWI interventions lasting 3 days [2] to 4 weeks [3] do not result in changes in TBW. Current evidence would suggest that the benefits of increasing TWI are not related changes in TBW.
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Sodium chloride 0.9% versus Lactated Ringer in the management of severely dehydrated patients with choleriform diarrhoea.
Cieza, JA, Hinostroza, J, Huapaya, JA, León, CP
Journal of infection in developing countries. 2013;(7):528-32
Abstract
INTRODUCTION Although experience within Peru suggests clinical and physiological benefits of treating dehydration caused by diarrhoea with Lactated Ringer's solution (LR) over sodium chloride 0.9%, (NaCl) there is little documented scientific evidence supporting this view. It is important to clarify this issue and determine the best solution for use during epidemics. METHODOLOGY Forty patients suffering from dehydration due to choleriform diarrhoea were enrolled in the study. Twenty patients were treated using NaCl (Group A) and the other twenty with LR (Group B). After diuresis recovery was achieved, the patients were continued on a course of oral rehydration salts. Serum electrolytes, arterial pH, HCO3-, and pCO2 were measured at three stages: at admission, after diuresis recovery, and after 12 hours. RESULTS Acidosis was corrected more quickly with LR that NaCl. The hyperosmolality and hypernatremic states were corrected with both solutions. CONCLUSION LR use resulted in a better clinical response than NaCl, illustrated by more rapid physiological correction, showing that mixed metabolic acidosis was corrected more quickly and more appropriately with this treatment.
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The different effects of fluid with and without carbohydrate ingestion on subjective responses of untrained men during prolonged exercise in a hot environment.
Ishijima, T, Hashimoto, H, Satou, K, Muraoka, I, Suzuki, K, Higuchi, M
Journal of nutritional science and vitaminology. 2009;(6):506-10
Abstract
This study examined the effects of maintaining euhydration by ingesting fluids with or without carbohydrate on subjective responses of untrained men during prolonged exercise in a hot environment. Six healthy untrained subjects completed 90 min of cycling exercises at 55% maximal oxygen consumption (V(O2max)) in a hot environment (temperature: 28(o)C, humidity: 50%) under three different experimental conditions. During the first trial, subjects did not ingest fluids during exercise (dehydration (DH) trial). In the second and third trials, subjects received mineral water (MW) and hypotonic fluid containing carbohydrate (HF), respectively, in amounts equaling their weight loss in the DH trial. At the end of exercise, the overall rating of perceived exertion (RPE-O) was lower in the MW and HF trials than in the DH trial (14.3+/-1.0 and 13.7+/-0.6 vs 17.7+/-1.0, p<0.05, respectively). RPE-cardiovascular and RPE-legs were lower at the end of exercise in the HF trial compared with the DH trial. V(O2), heart rate (HR), and rectal temperature increased during exercise in the three trials. At the end of exercise, the drift in V(O2) was lower in the MW and HF trials than in the DH trial (304+/-41 and 339+/-40 vs 458+/-33 mL, p<0.05, respectively). HR at the end of exercise in the HF trial was lower than in the DH trial (158+/-5 vs 173+/-7 bpm, p<0.05). These results suggest that maintaining euhydration during prolonged exercise in untrained men could attenuate RPE-O and that hypotonic electrolyte-carbohydrate solution could attenuate RPE-legs during exercise.
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Phase I and pharmacokinetic study of the novel chemoprotector BNP7787 in combination with cisplatin and attempt to eliminate the hydration schedule.
Boven, E, Westerman, M, van Groeningen, CJ, Verschraagen, M, Ruijter, R, Zegers, I, van der Vijgh, WJ, Giaccone, G
British journal of cancer. 2005;(9):1636-43
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Abstract
BNP7787 (disodium 2,2'-dithio-bis-ethane sulphonate; Tavocept) is a novel agent developed to protect against cisplatin (cis-diammine-dichloroplatinum(II))-associated chronic toxicities. In this study, we determined the recommended dose of BNP7787 when preceding a fixed dose of cisplatin, the pharmacokinetics (PKs) and the possible reduction of saline hydration. Patients with advanced solid tumours received BNP7787 in escalating doses of 4.1-41 g m(-2) as a 15-min intravenous (i.v.) infusion followed by cisplatin 75 mg m(-2) as a 60-min i.v. infusion together with pre- and postcisplatin saline hydration in a volume of 2200 ml; cycles were repeated every 3 weeks. PK was carried out using BNP7787, cisplatin and the combination. Twenty-five patients were enrolled in stage I of the study to determine the recommended dose of BNP7787. No dose-limiting toxicity was reached. The highest dose level of 41 g m(-2) resulted in a low incidence of grade 2 toxicities, being nausea and vomiting, dry mouth or bad taste and i.v. injection site discomfort. Doses of BNP7787 > or = 18.4 g m(-2) did not show a drug interaction between BNP7787 and cisplatin. In stage II of the study, patients received a fixed dose of BNP7787 of 18.4 g m(-2) preceding cisplatin and were entered in prespecified reduced saline hydration steps. A total of 21 patients in cohorts of six to nine patients received reduced saline hydration of 1600 ml (step A), 1000 ml (step B) and 500 ml (step C). In step C, two out of six evaluable patients experienced grade 1 nephrotoxicity. Cisplatin acute toxicities in all 46 patients were as expected. Only five patients complained of paresthesias grade 1 and six developed slight audiometric changes. Partial tumour response was observed in four patients and stable disease in 15 patients. In conclusion, BNP7787 was tolerated well up to doses of 41 g m(-2). The recommended dose of 18.4 g m(-2) enabled safe reduction of the saline hydration schedule for cisplatin to 1000 ml. Further studies will assess whether BNP7787 offers protection against platinum-related late side effects.
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Effect of hydration status on thirst, drinking, and related hormonal responses during low-intensity exercise in the heat.
Maresh, CM, Gabaree-Boulant, CL, Armstrong, LE, Judelson, DA, Hoffman, JR, Castellani, JW, Kenefick, RW, Bergeron, MF, Casa, DJ
Journal of applied physiology (Bethesda, Md. : 1985). 2004;(1):39-44
Abstract
During exercise-heat stress, ad libitum drinking frequently fails to match sweat output, resulting in deleterious changes in hormonal, circulatory, thermoregulatory, and psychological status. This condition, known as voluntary dehydration, is largely based on perceived thirst. To examine the role of preexercise dehydration on thirst and drinking during exercise-heat stress, 10 healthy men (21 +/- 1 yr, 57 +/- 1 ml x kg(-1) x min(-1) maximal aerobic power) performed four randomized walking trials (90 min, 5.6 km/h, 5% grade) in the heat (33 degrees C, 56% relative humidity). Trials differed in preexercise hydration status [euhydrated (Eu) or hypohydrated to -3.8 +/- 0.2% baseline body weight (Hy)] and water intake during exercise [no water (NW) or water ad libitum (W)]. Blood samples taken preexercise and immediately postexercise were analyzed for hematocrit, hemoglobin, serum aldosterone, plasma osmolality (P(osm)), plasma vasopressin (P(AVP)), and plasma renin activity (PRA). Thirst was evaluated at similar times using a subjective nine-point scale. Subjects were thirstier before (6.65 +/- 0.65) and drank more during Hy+W (1.65 +/- 0.18 liters) than Eu+W (1.59 +/- 0.41 and 0.31 +/- 0.11 liters, respectively). Postexercise measures of P(osm) and P(AVP) were significantly greater during Hy+NW and plasma volume lower [Hy+NW = -5.5 +/- 1.4% vs. Hy+W = +1.0 +/- 2.5% (P = 0.059), Eu+NW = -0.7 +/- 0.6% (P < 0.05), Eu+W = +0.5 +/- 1.6% (P < 0.05)] than all other trials. Except for thirst and drinking, however, no Hy+W values differed from Eu+NW or Eu+W values. In conclusion, dehydration preceding low-intensity exercise in the heat magnifies thirst-driven drinking during exercise-heat stress. Such changes result in similar fluid regulatory hormonal responses and comparable modifications in plasma volume regardless of preexercise hydration state.
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The effect of fluid consumption on the forest workers' performance strategy.
Wästerlund, DS, Chaseling, J, Burström, L
Applied ergonomics. 2004;(1):29-36
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The heart rate development and time consumption of four Zimbabwean forest workers engaged in manual harvesting were studied to assess their performance strategy and whether this strategy was affected by differences in fluid consumption. Each worker was studied during 8 consecutive working days and produced 2.4 m3 pulpwood/day. They consumed either 0.17 l or 0.6 l of water each 1/2 hour with one fluid scheme assigned to each day according to a randomised block (person) design with four replicates (days). All workers were found to harvest large trees at the start of the working day and small trees at the end. All workers took longer to complete their task when on the low fluid scheme, however, the effect on the heart rate development varied for the individual workers as the strategies adopted to accommodate the stress inflicted by the low fluid scheme, varied for the individual workers. It is recommended that sufficient fluid supply during work be accompanied by training of the workers to convey the need and benefits of sufficient fluid consumption.
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Rehydration after exercise with fresh young coconut water, carbohydrate-electrolyte beverage and plain water.
Saat, M, Singh, R, Sirisinghe, RG, Nawawi, M
Journal of physiological anthropology and applied human science. 2002;(2):93-104
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Abstract
This is to cross-over study to assess the effectiveness of fresh young coconut water (CW), and carbohydrate-electrolyte beverage (CEB) compared with plain water (PW) for whole body rehydration and blood volume (BV) restoration during a 2 h rehydration period following exercise-induced dehydration. Eight healthy male volunteers (mean age and VO2max of 22.4 +/- 3.3 years and 45.8 +/- 1.5 ml min kg-1 respectively) exercised at 60% of VO2max in the heat (31.1 +/- 0.03 degrees C, 51.4 +/- 0.1% rh) until 2.78 +/- 0.06% (1.6 +/- 0.1 kg) of their body weight (BW) was lost. After exercise, the subjects sat for 2 h in a thermoneutral environment (22.5 +/- 0.1 degrees C; 67.0 +/- 1.0% rh) and drank a volume of PW, CW and CEB on different occasions representing 120% of the fluid loss. A blood and urine sample, and the body weight of each subject was taken before and after exercise and at 30 min intervals throughout a rehydration period. Each subject remained fasted throughout rehydration. Each fluid was consumed in three portions in separate trials representing 50% (781 +/- 47 ml), 40% (625 +/- 33 ml) and 30% (469 +/- 28 ml) of the 120% fluid loss at 0, 30 and 60 min of the 2 h rehydration period, respectively. The drinks given were randomised. In all the trials the subjects were somewhat hypohydrated (range 0.08-0.18 kg BW below euhydrated BW; p > 0.05) after a 2 h rehydration period since additional water and BW were lost as a result of urine formation, respiration, sweat and metabolism. The percent of body weight loss that was regained (used as index of percent rehydration) during CW, PW, and CEB trials was 75 +/- 5%, 73 +/- 5% and 80 +/- 4% respectively, but was not statistically different between trials. The rehydration index, which provided an indication of how much of what was actually ingested was used for body weight restoration, was again not different statistically between trials (1.56 +/- 0.14, 1.36 +/- 0.13 and 1.71 +/- 0.21 for CW, CEB and PW respectively). Although BV restoration was better with CW, it was not statistically different from CEB and PW. Cumulative urine output was similar in all trials. There were no difference at any time in serum Na+ and Cl-, serum osmolality, and net fluid balance between the three trials. Urine osmolality decreased after 1 h during the rehydration period and it was lowest in the PW trial. Plasma glucose concentrations were significantly higher compared with PW ingestion when CW and CEB were ingested during the rehydration period. CW was significantly sweeter, caused less nausea, fullness and no stomach upset and was also easier to consume in a larger amount compared with CEB and PW ingestion. In conclusion, ingestion of fresh young coconut water, a natural refreshing beverage, could be used for whole body rehydration after exercise.
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Dehydration and body fluid-regulating hormones during sweating in warm (38 degrees C) fresh- and seawater immersion.
Hope, A, Aanderud, L, Aakvaag, A
Journal of applied physiology (Bethesda, Md. : 1985). 2001;(4):1529-34
Abstract
Body weight (BW) reductions of more than 4 kg have been observed during diving with the open hot water suit, a technique in which heated seawater (SW) continuously floods the skin surface. To test the hypothesis that osmotic effects may be involved in these fluid-loss processes, head-out immersion experiments in 38 degrees C freshwater (FW) and SW for 4 h were performed. Average BW reduction was 2.5 and 1.9 kg in SW and FW head-out immersion, respectively (P < 0.01). Atrial natriuretic peptide increased during the first 30 min of SW immersion (5.6-13.4 pmol/l, P < 0.01) followed by a reduction to 7.6 pmol/l (P < 0.01). This paralleled an initial decrease in aldosterone (from 427 to 306 pmol/l, P < 0.05) followed by an increase to 843 pmol/l (P < 0.01). The effects of temperature on fluid loss were studied in thermoneutral (34.5 degrees C) and 38 degrees C SW for 2 h. In thermoneutral SW, calculated sweat production was negligible (0.05 kg) compared with 1.2 kg in warm SW. We recommend that, if a dive is planned to last for more than 4 h, a mandatory break for fluid intake should be incorporated in the diving regulations.