Hypervolemia and plasma vasopressin response during water immersion in men

Greenleaf, J. E.; Morse, J. T.; Barnes, P.R.; Silver, Judith; Keil, L. C.

doi:10.1152/jappl.1983.55.6.1688

Cited by 37 publications

(18 citation statements)

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“…Body temperature must be elevated if dehydration occurs with decreasing sweat rate (Sawka et al 2001), because sweating is accompanied by loss of body fluid; however, the sweat rate at body temperature was not significantly different between PRE and POST in our study. The reduction of total body water or PV could activate the renin-angiotensin-aldosterone system (Greenleaf et al 1983;Hubschle et al 2001). In our study, plasma volume decreased by approximately 10% from the 1st to the 5th day and remained decreased until the 20th day of HDBR.…”

Section: Discussionsupporting

confidence: 48%

Effects of encouraged water drinking on thermoregulatory responses after 20 days of head-down bed rest in humans

et al. 2009

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We tested the hypothesis that encouraged water drinking according to urine output for 20 days could ameliorate impaired thermoregulatory function under microgravity conditions. Twelve healthy men, aged 24 +/- 1.5 years (mean +/- SE), underwent -6 degrees head-down bed rest (HDBR) for 20 days. During bed rest, subjects were encouraged to drink the same amount of water as the 24-h urine output volume of the previous day. A heat exposure test consisting of water immersion up to the knees at 42 degrees C for 45 min after a 10 min rest (baseline) in the sitting position was performed 2 days before the 20-day HDBR (PRE), and 2 days after the 20-day HDBR (POST). Core temperature (tympanic), skin temperature, skin blood flow and sweat rate were recorded continuously. We found that the -6 degrees HDBR did not increase the threshold temperature for onset of sweating under the encouraged water drinking regime. We conclude that encouraged water drinking could prevent impaired thermoregulatory responses after HDBR.

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Section: Discussionsupporting

confidence: 48%

Effects of encouraged water drinking on thermoregulatory responses after 20 days of head-down bed rest in humans

et al. 2009

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“…Most thermoneutral immersion (McCally 1964;Khosla and DuBois 1979;Harrison et al 1986;Ertl et al 1991), and all cold-water immersion studies have employed this indirect technique. However, a discrepancy in the indirectly-measured PV and Evans blue dye results during thermoneutral immersion was observed by Greenleaf et al (1983). Subsequently, Johansen et al (1992Johansen et al ( , 1995 demonstrated this approximation to underestimate the ''true'' PV response during thermoneutral immersion, as determined using a direct tracerdilution technique.…”

Section: Introductionmentioning

confidence: 99%

Direct and indirect methods for determining plasma volume during thermoneutral and cold-water immersion

et al. 2003

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Plasma volume (PV), determined indirectly from changes in haematocrit (Hct) and haemoglobin concentration ([Hb]), underestimates the absolute PV change (Evans blue dye) during thermoneutral immersion. Since PV changes during cold-water immersion have only been determined indirectly, we hypothesised that a similar underestimation may occur. Therefore, we compared the indirectly-measured PV with a direct-tracer dilution method (Evans blue dye column elution) in seven healthy males, during three, 60-min exposures: air (control; 21.2 degrees C), thermoneutral immersion (34.5 degrees C) and cold-water immersion (18.6 degrees C). During thermoneutral immersion, the directly-measured PV increased by 16.2 (1.4)% (P<0.05) and the indirectly-measured by 8.5 (0.8)% (P<0.05), with the latter underestimating the former by 43 (9.1)% (P<0.05). During cold immersion, the direct PV decreased by 17.9 (3.0)% (P<0.05) and the indirect by 8.0 (1.2)% (P<0.05), with the latter representing a 52 (6.8)% (P<0.05) underestimation of the direct PV change. Directionally-equivalent underestimations of PV change occur when using the indirect method during both thermoneutral and cold-water immersion. The assumptions inherent in the indirect method (constant F-cell ratio) appear to be violated during water immersion.

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“…Accompanying the increased urine production is an increased loss of sodium (Na) and potassium (K) ions (natriuresis and kaliuresis) (Epstein et al 1975;Epstein 1978). These physiologic responses occur when subjects aze immersed in either cold Doubt et al 1988;Young et al 1987) or thermoneutral water (Epstein 1978;Greenleaf et al 1980;Greenleaf et al 1981;Greenleaf et al 1983;McCalley 1964). Exposure to cold air alone significantly increases diuresis and plasma volume loss (Young et al 1987); however, cold water immersion produces a more powerful stimulus Trippodo et al 1983).…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of Glycerol Ingestion for Enhanced Body Water Retention during Cold Water Immersion

Goforth¹,

Arnall²

1989

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SUMMARYThe efficacy of ingesting an aqueous glycerol (GLY) solution to reduce diuresis and enhance body water retention during prolonged cold water dives was evaluated. Nine Navy divers 131 ± 5 years, height 175.0 ± 4.5 centimeters (cm), weight 78.9 ± 9.5 kilograms (kg), and 16 ± 2 percent (%) body fat] performed three-hour dives at 5 feet fresh water (FFW) maintained at 13*C.Divers wore thermal undergarments and dry suits and used a closed-circuit (MK-15) rebreathing unit. Six subjects were assigned to either a water treatment (VT) or glycerol treatment (GT) group. Three other divers performed a repeated measures design with dives separated by a day of nondiving. Statistical analyses of data from repeated and nonrepeated subjects consistently revealed no significant differences between and within these groups of subjects. Data were thus pooled into two treatment groups (VT . 6) and (GT -6).During the predive period, Serum glucose (sCLU) and serum lactate (sLAC) did not differ between treatments or times, but sLAC was significantly lover (P < 0.02) for both treatments at PD than at PH. Serum free fatty acids (sFFA) at PD for both treatments were significantly higher (P < 0.2) than at PRH and PH. Serum glycerol (sGLY) values for GT were 200 times above PRH at PH and 100 times ahn,'e PRH at PD. The amount of urinary glycerol (uGLY) rolected during the hyperhydration period (PRH to PH) and the thr'ýc-hotr dive periods accounted for 2 4.1Z and 10.3Z, respectively, of the total GLY ingested.Urine electrolyte values did not differ between treatments, except GT lost significantly (P < 0.02) more sodium (Na) [53.7 + 9.9 versus 21.6 + 6.2 milliequivalent per liter (meq/1)] during the PH period. Hyperhydratien with GLY (1.2 ml/kg LBM) mixed in 2 liters of water and consumed over 30 minutes appears ineffective in significantly reducing body water loss in divers under the stress of prolonged cold water immersion. It may be that altering the timing and/or concentration of the GLY doses will produce a significant effect under these test conditions.

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Hypervolemia and plasma vasopressin response during water immersion in men

Cited by 37 publications

References 0 publications

Effects of encouraged water drinking on thermoregulatory responses after 20 days of head-down bed rest in humans

Effects of encouraged water drinking on thermoregulatory responses after 20 days of head-down bed rest in humans

Direct and indirect methods for determining plasma volume during thermoneutral and cold-water immersion

Effectiveness of Glycerol Ingestion for Enhanced Body Water Retention during Cold Water Immersion

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