scholarly journals Human thermoregulation during prolonged exposure to warm and extremely humid environments expected to occur in disabled submarine scenarios

2020 ◽  
Vol 318 (5) ◽  
pp. R950-R960 ◽  
Author(s):  
Zachary J. Schlader ◽  
Blair D. Johnson ◽  
Riana R. Pryor ◽  
Jocelyn Stooks ◽  
Brian M. Clemency ◽  
...  
Keyword(s):  
Body Weight ◽  
Core Temperature ◽  
Body Fluid ◽  
Prolonged Exposure ◽  
Linear Regression Models ◽  
Emergency Situations ◽  
Temperature Telemetry ◽  
Uncompensable Heat Stress ◽  
Total Body ◽  
Fluid Losses

Military and civilian emergency situations often involve prolonged exposures to warm and very humid environments. We tested the hypothesis that increases in core temperature and body fluid losses during prolonged exposure to warm and very humid environments are dependent on dry bulb temperature. On three occasions, 15 healthy males (23 ± 3 yr) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C, or 35.0 ± 0.1°C and 95 ± 2% relative humidity normobaric environments for 8 h. Core temperature (telemetry pill) and percent change in body weight, an index of changes in total body water occurring secondary to sweat loss, were measured every hour. Linear regression models were fit to core temperature (over the final 4 h) and percent changes in body weight (over the entire 8 h) for each subject. These equations were used to predict core temperature and percent changes in body weight for up to 24 h. At the end of the 8-h exposure, core temperature was higher in 35°C (38.2 ± 0.4°C, P < 0.01) compared with 32°C (37.2 ± 0.2°C) and 33°C (37.5 ± 0.2°C). At this time, percent changes in body weight were greater in 35°C (−1.9 ± 0.5%) compared with 32°C (−1.4 ± 0.3%, P < 0.01) but not 33°C (−1.6 ± 0.6%, P = 0.17). At 24 h, predicted core temperature was higher in 35°C (39.2 ± 1.4°C, P < 0.01) compared with 32°C (37.6 ± 0.9°C) and 33°C (37.5 ± 0.9°C), and predicted percent changes in body weight were greater in 35°C (−6.1 ± 2.4%) compared with 32°C (−4.6 ± 1.5%, P = 0.04) but not 33°C (−5.3 ± 2.0%, P = 0.43). Prolonged exposure to 35°C, but not 32°C or 33°C, dry bulb temperatures and high humidity is uncompensable heat stress, which exacerbates body fluid losses.

HEMATOLOGICAL AND BODY FLUID ADJUSTMENTS DURING ACCLIMATION TO A COLD ENVIRONMENT

1956 ◽  
Vol 34 (5) ◽  
pp. 959-966 ◽  
Author(s):  
C. Deb ◽  
J. S. Hart
Keyword(s):  
Body Weight ◽  
Specific Gravity ◽  
Total Body Water ◽  
Body Fluid ◽  
Extracellular Fluid ◽  
Body Water ◽  
Cold Environment ◽  
Cell Counts ◽  
Total Body ◽  
Absolute Basis

Body fluid volumes and hematological values have been compared in rats exposed to 6 °C. for various periods of time and in rats at 30 °C. for comparable periods. Absolute blood and plasma volumes (T1824 space) decreased with time of exposure to 30 °C, while extracellular fluid volume (sodium space), total body water, and body weight increased. Rats transferred from the warm to the cold environment had larger plasma and blood volumes than those of rats at 30 °C. after the first week of exposure. After five weeks, blood volume was 22% greater on an absolute basis and 30% greater relative to total body water than that of the larger rats at 30 °C. There were no differences in extracellular fluid volumes between warm and cold exposed rats at comparable intervals. Total water and intracellular water tended to be greater in rats at 30 °C. on an absolute basis but they were much greater per unit body weight in rats at 6 °C. No differences were observed in red blood cell counts, in hemoglobin concentration, or in plasma specific gravity between warm and cold exposed rats, but there was an increased hematocrit, increased corpuscular volume, and decreased corpuscular hemoglobin content in rats kept at 6 °C. Hemoglobin, red cells, and plasma specific gravity increased with time in both groups.

Metabolic Profile of the Ironman World Championships: A Case Study

2010 ◽  
Vol 5 (4) ◽  
pp. 570-576 ◽  
Author(s):  
John S. Cuddy ◽  
Dustin R. Slivka ◽  
Walter S. Hailes ◽  
Charles L. Dumke ◽  
Brent C. Ruby
Keyword(s):  
Body Weight ◽  
Energy Expenditure ◽  
Muscle Glycogen ◽  
Metabolic Profile ◽  
Linear Regression Models ◽  
Water Turnover ◽  
World Championship ◽  
Wet Weight ◽  
Total Body

Purpose:The purpose of this study was to determine the metabolic profile during the 2006 Ironman World Championship in Kailua-Kona, Hawaii.Methods:One recreational male triathlete completed the race in 10:40:16. Before the race, linear regression models were established from both laboratory and feld measures to estimate energy expenditure and substrate utilization. The subject was provided with an oral dose of 2H218O approximately 64 h before the race to calculate total energy expenditure (TEE) and water turnover with the doubly labeled water (DLW) technique. Body weight, blood sodium and hematocrit, and muscle glycogen (via muscle biopsy) were analyzed pre- and postrace.Results:The TEE from DLW and indirect calorimetry was similar: 37.3 MJ (8,926 kcal) and 37.8 MJ (9,029 kcal), respectively. Total body water turnover was 16.6 L, and body weight decreased 5.9 kg. Hematocrit increased from 46 to 51% PCV. Muscle glycogen decreased from 152 to 48 mmoL/kg wet weight pre- to postrace.Conclusion:These data demonstrate the unique physiological demands of the Ironman World Championship and should be considered by athletes and coaches to prepare sufficient nutritional and hydration plans.

scholarly journals The effect of acute dehydration on agility, quickness and balance performance in elite wrestlers

2021 ◽  
Vol 25 (3) ◽  
pp. 149-157
Author(s):  
Sevilay Kaplan ◽  
Ali O. Kivrak
Keyword(s):  
Body Mass Index ◽  
Body Weight ◽  
Body Fluid ◽  
Body Fat Percentage ◽  
Balance Performance ◽  
Fat Percentage ◽  
Eyes Closed ◽  
Eyes Open ◽  
The Mean ◽  
Total Body

Background and Study Aim.  The aim of this study was to investigate the effect of acute dehydration on agility, quickness and balance performance in elite wrestlers. Material and Methods. A total of 12 male elite wrestlers, who were student at Selçuk University Faculty of Sport Sciences, whose mean age was 21.58±1.44 years, the mean height of 176.67±5.87 cm, mean body weight of 74.25±17.79 kg, and the mean age of sports 8.92±1,44 years have participated the study voluntarily. After taking the height measurement of the wrestlers participating in the study, their masses were weighted before the training; and body mass index, body fat percentage, muscle mass, and total body fluid were taken with Tanita Bc 730 and agility, quickness (5 m) and balance performance tests were performed. Then, by limiting the fluid intake of the athletes, after losing weight by training, the same tests that were applied before the training applied to the athletes after the training. The study was conducted in accordance with the pre-test and post-test model. T test was used for agility performance measurement of the athletes and 5 m test was used for quickness performance. Dominant foot was determined for balance test and measurement was made via Biodex Balance System. Balance measurements were performed eyes open (EO) and eyes closed (EC), overall stability index (OSI). Results.  In this study, body weight, body mass index, total body fluid, agility, quickness and balance with eyes open mean values were found to be statistically significant (p<0.05), and muscle mass, body fat percentage, balance with eyes closed found not to be statistically significant (p> 0.05). Conclusions. It is believed that acute dehydration negatively affects agility, quickness and balance performances in wrestlers. 

Body Fluid Spaces in Patients on CAPD

1984 ◽  
Vol 7 (2) ◽  
pp. 89-91 ◽  
Author(s):  
G. Panzetta ◽  
U. Guerra ◽  
A. D'angelo ◽  
S. Sandrini ◽  
A. Terzi ◽  
...  
Keyword(s):  
Body Weight ◽  
Distinctive Feature ◽  
Total Body Water ◽  
Body Fluid ◽  
Mean Value ◽  
Body Water ◽  
Extracellular Water ◽  
Intracellular Space ◽  
The Mean ◽  
Total Body

Total body water (TBW) and extracellular water (ECW) were determined in 9 CAPD patients on treatment from 5 to 14 months (mean 8.6 months). The mean value of TBW was normal and directly correlated to body weight, but TBW was abnormally distributed between extracellular and intracellular space. ECW volume was significantly lower than the predicted value (12.1 ± 1.4 I versus 16.8 ± 1.9 I) and out of proportion to TBW (34.8 ± 3.9% versus 47.8 ± 1.5%). The calculated ICW, therefore, appeared clearly hyperexpanded. The data suggest that cell overhydration was the distinctive feature in our CAPD patients.

Total Body Fluid Volume Determination Based on Urea Kinetics in Hemofiltration as an Index of Basal Body Weight in Uremic Patients

1986 ◽  
Vol 9 (3) ◽  
pp. 159-162 ◽  
Author(s):  
G. Kimura ◽  
M. Satani ◽  
S. Kojima ◽  
F. Saito ◽  
Y. Kawano ◽  
...  
Keyword(s):  
Body Weight ◽  
Basal Body ◽  
Body Fluid ◽  
Fluid Volume ◽  
Artificial Kidney ◽  
Volume Determination ◽  
Urea Kinetics ◽  
Body Fluid Volume ◽  
Uremic Patients ◽  
Total Body

Assuming that urea is distributed uniformly within the total body water, urea-space or total body fluid volume was determined in six uremic patients based on urea kinetics in hemofiltration. The total body fluid volume before hemofiltration was 36.0 ± 3.6 L (61.8 ± 2.6% BW) and after hemofiltration 32.5 ± 3.4 L (59.3 ± 2.8% BW), suggesting that the total body fluid volume was nearly normalized by hemofiltration. It is concluded that urea-space, easily measurable based on urea kinetics during hemofiltration, is useful in evaluating the fluid balance in patients undergoing artificial kidney therapy.

Operation Everest. II: Nutrition and body composition

1988 ◽  
Vol 65 (6) ◽  
pp. 2545-2551 ◽  
Author(s):  
M. S. Rose ◽  
C. S. Houston ◽  
C. S. Fulco ◽  
G. Coates ◽  
J. R. Sutton ◽  
...  
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Prolonged Exposure ◽  
Caloric Intake ◽  
Body Weight Loss ◽  
Total Body Weight ◽  
Environmental Variable ◽  
High Mountain ◽  
Sufficient Cause ◽  
Total Body

Progressive body weight loss occurs during high mountain expeditions, but whether it is due to hypoxia, inadequate diet, malabsorption, or the multiple stresses of the harsh environment is unknown. To determine whether hypoxia due to decompression causes weight loss, six men, provided with a palatable ad libitum diet, were studied during progressive decompression to 240 Torr over 40 days in a hypobaric chamber where hypoxia was the major environmental variable. Caloric intake decreased 43.0% from 3,136 to 1,789 kcal/day (P less than 0.001). The percent carbohydrate in the diet decreased from 62.1 to 53.2% (P less than 0.001). Over the 40 days of the study the subjects lost 7.4 +/- 2.2 (SD) kg and 1.6% (2.5 kg) of the total body weight as fat. Computerized tomographic scans indicated that most of the weight loss was derived from fat-free weight. The data indicated that prolonged exposure to the increasing hypoxia was associated with a reduction in carbohydrate preference and body weight despite access to ample varieties and quantities of food. This study suggested that hypoxia can be sufficient cause for the weight loss and decreased food consumption reported by mountain expeditions at high altitude.

HEMATOLOGICAL AND BODY FLUID ADJUSTMENTS DURING ACCLIMATION TO A COLD ENVIRONMENT

1956 ◽  
Vol 34 (1) ◽  
pp. 959-966 ◽  
Author(s):  
C. Deb ◽  
J. S. Hart
Keyword(s):  
Body Weight ◽  
Specific Gravity ◽  
Total Body Water ◽  
Body Fluid ◽  
Extracellular Fluid ◽  
Body Water ◽  
Cold Environment ◽  
Cell Counts ◽  
Total Body ◽  
Absolute Basis

Body fluid volumes and hematological values have been compared in rats exposed to 6 °C. for various periods of time and in rats at 30 °C. for comparable periods. Absolute blood and plasma volumes (T1824 space) decreased with time of exposure to 30 °C, while extracellular fluid volume (sodium space), total body water, and body weight increased. Rats transferred from the warm to the cold environment had larger plasma and blood volumes than those of rats at 30 °C. after the first week of exposure. After five weeks, blood volume was 22% greater on an absolute basis and 30% greater relative to total body water than that of the larger rats at 30 °C. There were no differences in extracellular fluid volumes between warm and cold exposed rats at comparable intervals. Total water and intracellular water tended to be greater in rats at 30 °C. on an absolute basis but they were much greater per unit body weight in rats at 6 °C. No differences were observed in red blood cell counts, in hemoglobin concentration, or in plasma specific gravity between warm and cold exposed rats, but there was an increased hematocrit, increased corpuscular volume, and decreased corpuscular hemoglobin content in rats kept at 6 °C. Hemoglobin, red cells, and plasma specific gravity increased with time in both groups.

scholarly journals Lean body weight versus total body weight to calculate the iodinated contrast media volume in abdominal CT: a randomised controlled trial

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Moreno Zanardo ◽  
Fabio Martino Doniselli ◽  
Anastassia Esseridou ◽  
Massimiliano Agrò ◽  
Nicol Antonina Rita Panarisi ◽  
...  
Keyword(s):  
Body Weight ◽  
Contrast Media ◽  
Controlled Trial ◽  
Total Body Weight ◽  
Lean Body Weight ◽  
Iodinated Contrast Media ◽  
Abdominal Ct ◽  
Iodinated Contrast ◽  
Significant Difference ◽  
Total Body

Abstract Objectives Iodinated contrast media (ICM) could be more appropriately dosed on patient lean body weight (LBW) than on total body weight (TBW). Methods After Ethics Committee approval, trial registration NCT03384979, patients aged ≥ 18 years scheduled for multiphasic abdominal CT were randomised for ICM dose to LBW group (0.63 gI/kg of LBW) or TBW group (0.44 gI/kg of TBW). Abdominal 64-row CT was performed using 120 kVp, 100–200 mAs, rotation time 0.5 s, pitch 1, Iopamidol (370 mgI/mL), and flow rate 3 mL/s. Levene, Mann–Whitney U, and χ2 tests were used. The primary endpoint was liver contrast enhancement (LCE). Results Of 335 enrolled patients, 17 were screening failures; 44 dropped out after randomisation; 274 patients were analysed (133 LBW group, 141 TBW group). The median age of LBW group (66 years) was slightly lower than that of TBW group (70 years). Although the median ICM-injected volume was comparable between groups, its variability was larger in the former (interquartile range 27 mL versus 21 mL, p = 0.01). The same was for unenhanced liver density (IQR 10 versus 7 HU) (p = 0.02). Median LCE was 40 (35–46) HU in the LBW group and 40 (35–44) HU in the TBW group, without significant difference for median (p = 0.41) and variability (p = 0.23). Suboptimal LCE (< 40 HU) was found in 64/133 (48%) patients in the LBW group and 69/141 (49%) in the TBW group, but no examination needed repeating. Conclusions The calculation of the ICM volume to be administered for abdominal CT based on the LBW does not imply a more consistent LCE.

scholarly journals Effects of a 14-Day Hydration Intervention on Individuals with Habitually Low Fluid Intake

2021 ◽  
Author(s):  
Aaron R. Caldwell ◽  
Megan E. Rosa-Caldwell ◽  
Carson Keeter ◽  
Evan C. Johnson ◽  
François Péronnet ◽  
...  
Keyword(s):  
Body Weight ◽  
Total Body Water ◽  
Fluid Intake ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Body Water ◽  
Control Group ◽  
Intervention Phase ◽  
Total Body ◽  
Experimental Group

<b><i>Background:</i></b> 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) [<xref ref-type="bibr" rid="ref1">1</xref>]. 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) [<xref ref-type="bibr" rid="ref2">2</xref>]. In a small (<i>n</i> = 5) study of adult men, there were no observable changes in TBW, as measured by bioelectrical impedance, after increasing TWI for 4 weeks [<xref ref-type="bibr" rid="ref3">3</xref>]. 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. <b><i>Objectives:</i></b> 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. <b><i>Methods:</i></b> 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 (D<sub>2</sub>O) was administered to measure TBW. Urine samples were collected immediately prior, and 3–8 h after the D<sub>2</sub>O 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. <b><i>Results:</i></b> Twenty-four-hour urine osmolality decreased (−438.7 ± 362.1 mOsm; <i>p</i> &#x3c; 0.001) and urine volume increased (1,526 ± 869 mL; <i>p</i> &#x3c; 0.001) in the experimental group from baseline, while there were no differences in osmolality (−74.7 ± 572 mOsm; <i>p</i> = 0.45), or urine volume (−32 ± 1,376 mL; <i>p</i> = 0.89) in the control group. However, there were no changes in BV (Fig. <xref ref-type="fig" rid="f01">1</xref>a) or changes in TBW (Fig. <xref ref-type="fig" rid="f01">1</xref>b) in either group. <b><i>Conclusions:</i></b> 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 [<xref ref-type="bibr" rid="ref2">2</xref>] to 4 weeks [<xref ref-type="bibr" rid="ref3">3</xref>] do not result in changes in TBW. Current evidence would suggest that the benefits of increasing TWI are not related changes in TBW.

Nutritional Status of Patients Undergoing Continuous Ambulatory Peritoneal Dialysis (CAPD)

1983 ◽  
Vol 3 (3) ◽  
pp. 138-141 ◽  
Author(s):  
Brigitte Heide ◽  
Andreas Pierratos ◽  
Ramesh Khanna ◽  
Jean Pettit ◽  
Raymond Ogilvie ◽  
...  
Keyword(s):  
Body Weight ◽  
Peritoneal Dialysis ◽  
Nutritional Status ◽  
Continuous Ambulatory Peritoneal Dialysis ◽  
Protein Intake ◽  
Biochemical Parameters ◽  
Total Body Potassium ◽  
Total Body ◽  
Over Time

Nutritional follow-up of 20 CAPD patients for 18–24 months showed a decrease in total body nitrogen, increase in total body potassium and body weight, and a decrease in protein intake over time. There was no correlation between changes in TBN and the biochemical parameters measured. Serial dietetic assessments and measurements of total body nitrogen as well as adherence to an adequate protein intake will assist in the prevention of malnutrition in CAPD patients.

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