Carbohydrate exerts a mild influence on fluid retention following exercise-induced dehydration

2010 ◽  
Vol 108 (2) ◽  
pp. 245-250 ◽  
Author(s):  
Kristin L. Osterberg ◽  
Shannon E. Pallardy ◽  
Richard J. Johnson ◽  
Craig A. Horswill
Keyword(s):  
Body Mass ◽  
Urine Volume ◽  
Fluid Retention ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Excessive Sweating ◽  
Rehydration Solutions ◽  
Before And After ◽  
Postexercise Recovery ◽  
Exercise Induced

Rapid and complete rehydration, or restoration of fluid spaces, is important when acute illness or excessive sweating has compromised hydration status. Many studies have investigated the effects of graded concentrations of sodium and other electrolytes in rehydration solutions; however, no study to date has determined the effect of carbohydrate on fluid retention when electrolyte concentrations are held constant. The purpose of this study was to determine the effect of graded levels of carbohydrate on fluid retention following exercise-induced dehydration. Fifteen heat-acclimatized men exercised in the heat for 90 min with no fluid to induce 2–3% dehydration. After a 30-min equilibration period, they received, over the course of 60 min, one of five test beverages equal to 100% of the acute change in body mass. The experimental beverages consisted of a flavored placebo with no electrolytes (P), placebo with electrolytes (P + E), 3%, 6%, and 12% carbohydrate solutions with electrolytes. All beverages contained the same type and concentration of electrolytes (18 meq/l Na+, 3 meq/l K+, 11 meq/l Cl−). Subjects voided their bladders at 60, 90, 120, 180, and 240 min, and urine specific gravity and urine volume were measured. Blood samples were taken before exercise and 30, 90, 180, and 240 min following exercise and were analyzed for glucose, sodium, hemoglobin, hematocrit, renin, aldosterone, and osmolality. Body mass was measured before and after exercise and a final body mass was taken at 240 min. There were no differences in percent dehydration, sweat loss, or fluid intake between trials. Fluid retention was significantly greater for all carbohydrate beverages compared with P (66.3 ± 14.4%). P + E (71.8 ± 9.9%) was not different from water, 3% (75.4 ± 7.8%) or 6% (75.4 ± 16.4%) but was significantly less than 12% (82.4 ± 9.2%) retention of the ingested fluid. No difference was found between the carbohydrate beverages. Carbohydrate at the levels measured exerts a mild influence on fluid retention in postexercise recovery.

scholarly journals A Sodium Drink Enhances Fluid Retention During 3 Hours of Post-Exercise Recovery When Ingested With a Standard Meal

2017 ◽  
Vol 27 (4) ◽  
pp. 344-350 ◽  
Author(s):  
Gethin H. Evans ◽  
Jennifer Miller ◽  
Sophie Whiteley ◽  
Lewis J. James
Keyword(s):  
Body Mass ◽  
Intermittent Exercise ◽  
Urine Volume ◽  
Fluid Retention ◽  
Plain Water ◽  
Nacl Solution ◽  
Standard Meal ◽  
Before And After ◽  
Exercise Induced ◽  
Experimental Trials

The purpose of this study was to examine the efficacy of water and a 50 mmol/L NaCl solution on postexercise rehydration when a standard meal was consumed during rehydration. Eight healthy participants took part in two experimental trials during which they lost 1.5 ± 0.4% of initial body mass via intermittent exercise in the heat. Participants then rehydrated over a 60-min period with water or a 50 mmol/L NaCl solution in a volume equivalent to 150% of their body mass loss during exercise. In addition, a standard meal was ingested during this time which was equivalent to 30% of participants predicted daily energy expenditure. Urine samples were collected before and after exercise and for 3 hr after rehydration. Cumulative urine volume (981 ± 458 ml and 577 ± 345 mL; p = .035) was greater, while percentage fluid retained (50 ± 20% and 70 ± 21%; p = .017) was lower during the water compared with the NaCl trial respectively. A high degree of variability in results was observed with one participant producing 28% more urine and others ranging from 18–83% reduction in urine output during the NaCl trial. The results of this study suggest that after exercise induced dehydration, the ingestion of a 50 mmol/L NaCl solution leads to greater fluid retention compared with water, even when a meal is consumed postexercise. Furthermore, ingestion of plain water may be effective for maintenance of fluid balance when food is consumed in the rehydration period.

scholarly journals Effect of Drinking Rate on the Retention of Water or Milk Following Exercise-Induced Dehydration

2020 ◽  
Vol 30 (2) ◽  
pp. 128-138 ◽  
Author(s):  
Liam Sayer ◽  
Nidia Rodriguez-Sanchez ◽  
Paola Rodriguez-Giustiniani ◽  
Christopher Irwin ◽  
Danielle McCartney ◽  
...  
Keyword(s):  
Body Mass ◽  
Urine Volume ◽  
Gastrointestinal Symptoms ◽  
Plasma Osmolality ◽  
Fluid Retention ◽  
Urine Specific Gravity ◽  
Plain Water ◽  
Cycle Exercise ◽  
Drinking Rate ◽  
Exercise Induced

This study investigated the effect of drinking rate on fluid retention of milk and water following exercise-induced dehydration. In Part A, 12 male participants lost 1.9% ± 0.3% body mass through cycle exercise on four occasions. Following exercise, plain water or low-fat milk equal to the volume of sweat lost during exercise was provided. Beverages were ingested over 30 or 90 min, resulting in four beverage treatments: water 30 min, water 90 min, milk 30 min, and milk 90 min. In Part B, 12 participants (nine males and three females) lost 2.0% ± 0.3% body mass through cycle exercise on four occasions. Following exercise, plain water equal to the volume of sweat lost during exercise was provided. Water was ingested over 15 min (DR15), 45 min (DR45), or 90 min (DR90), with either DR15 or DR45 repeated. In both trials, nude body mass, urine volume, urine specific gravity and osmolality, plasma osmolality, and subjective ratings of gastrointestinal symptoms were obtained preexercise and every hour for 3 hr after the onset of drinking. In Part A, no effect of drinking rate was observed on the proportion of fluid retained, but milk retention was greater (p < .01) than water (water 30 min: 57% ± 16%, water 90 min: 60% ± 20%, milk 30 min: 83% ± 6%, and milk 90 min: 85% ± 7%). In Part B, fluid retention was greater in DR90 (57% ± 13%) than DR15 (50% ± 11%, p < .05), but this was within test–retest variation determined from the repeated trials (coefficient of variation: 17%). Within the range of drinking rates investigated the nutrient composition of a beverage has a more pronounced impact on fluid retention than the ingestion rate.

scholarly journals Amateur and Professional Ice Hockey Player Hydration Status and Urine Specific Gravity Values Before and After Training in Winter Conditions

2014 ◽  
Vol 5 (2) ◽  
pp. 53-61 ◽  
Author(s):  
Lilita Ozoliņa ◽  
Inese Pontaga ◽  
Igors Ķīsis
Keyword(s):  
Body Mass ◽  
The Body ◽  
Ice Hockey ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Fluid Loss ◽  
Winter Conditions ◽  
Hockey Players ◽  
Before And After ◽  
The Mean

Abstract The aim of our investigation was to determine and compare the pre- and post- training body hydration status in professional and amateur male ice hockey players consumed the drinks according to their thirst sensation in winter conditions. Materials and methods: 11 amateur and 23 professional ice hockey players participated in the investigation. The players were weighted before and after training using precise scales. The body mass composition of every athlete was determined by the body composition analyzer. Every player collected mid–stream urine specimens before and after the training. Urine specific gravity (USG) was measured by urine refractometer. Results: 56% of the professional ice hockey players and 82% of amateur players were hypohydrated before training according to their USG values ≥ 1.020, 5% of professional players were dehydrated their USG values ≥ 1.030. After the training with duration of 1.5 hours the mean body mass decreased for 0.9±0.5% of pre– training value in amateur players and for 1.6±0.8% in professionals (p=0.005). After the training the professional players’ hydration status worsened: 66% were hypohydrated and 26% dehydrated according to USG, the mean USG after training was significantly higher than before it (p=0.011). USG after training did not change in amateur players: their mean USG values before and after training did not differed significantly (p=0.677). Conclusions: Fluid uptake according to thirst sensation in winter conditions cannot compensate the fluid loss at rest and during training especially in professional ice hockey players. The body mass loss exceeded value critical for performance - 2 % in one third part of professionals. The differences between two groups can be explained by higher intensity of exercises during training, the better physical conditioning and greater sweating rate in professional players in comparison with amateurs, which causes close to twice greater uncompensated fluid loss in professionals than in amateurs.

scholarly journals The psychophysiological effects of a three day dry fast: A self-experimentation case study

2020 ◽  
Author(s):  
Harriet Carroll
Keyword(s):  
Blood Pressure ◽  
Blood Glucose ◽  
Specific Gravity ◽  
Sleep Quality ◽  
Body Mass ◽  
Urine Volume ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Fluid Restriction ◽  
Urine Colour

Background: A commonly held belief is that humans cannot survive more than a few days without fluid intake. The source of this is unclear, but does not accord with the few controlled studies that have been conducted to investigate the effects of fluid abstention, nor the few extreme cases of fluid restriction. Methods: This was a self-experimentation, with one day pre-load of fluid and salt (DAY 0), three days complete fluid abstention (&lt; 45 g/d water from food only) (DAYS 1-3), and 24 h rehydration (DAY 4). Days ran from 1500 h to 1500 h. The following measures were taken across various time points across each day: body mass; urine volume; urine colour; urine specific gravity; finger-prick blood glucose concentration; blood pressure; pulse; body temperature; dietary intake; and visual analogue scales (VAS) of food-appetites (satiety and desires), thirst-appetites, mood, wakefulness, and sleep quality. Results: By the end of DAY 3, body water (excluding estimated lean/adipose loss from negative energy balance) decreased by ~1.8 % from 1500 h on DAY 0, or ~4.0 % from 1500 h on DAY 1 (after a fluid preload). With this reduction in body mass came expected reductions in urine volume and increased in urine colour, though trends in urine specific gravity were less pronounced. Blood pressure trended towards being lower during DAYS 1-3 and increased during DAY 4. Whole blood glucose concentrations also tended towards being lower during DAYS 1-3 compared to DAY 4, particularly postprandially. Hunger tended to be reduced during DAYS 1-3, but increased again during DAY 4. Wanting to eat appeared to be a separate construct to hunger/fullness. True-thirst was higher during DAYS 1-3 relative to DAY 4, and this synchronised well with true-xerostomia and ratings of dryness of lips. However, sensational-xerostomia was the dominant thirst experienced during DAY 1-3. Sadness was moderately inversely correlated with body mass loss (r = 0.57) and tiredness was strongly positively correlated (r = 0.94). Sleep quality was unrelated to hydration status. Conclusion: Overall, the expected changes occurred in terms of hydration physiology, but with some unexpected findings in terms of gluco-regulation, blood pressure, and thirst appetites.

Hydration Status and Sodium Balance of Endurance Runners Consuming Postexercise Supplements of Varying Nutrient Content

2015 ◽  
Vol 25 (5) ◽  
pp. 471-479 ◽  
Author(s):  
J. Luke Pryor ◽  
Evan C. Johnson ◽  
Jeffery Del Favero ◽  
Andrew Monteleone ◽  
Lawrence E. Armstrong ◽  
...  
Keyword(s):  
Body Mass ◽  
Sodium Intake ◽  
Urine Volume ◽  
Nutrient Content ◽  
Urinary Sodium Excretion ◽  
Nutritional Supplement ◽  
Running Economy ◽  
Urine Specific Gravity ◽  
Sodium Balance ◽  
Hydration Status

Postexercise protein and sodium supplementation may aid recovery and rehydration. Preserved beef provides protein and contains high quantities of sodium that may alter performance related variables in runners. The purpose of this study was to determine the effects of consuming a commercial beef product postexercise on sodium and water balance. A secondary objective was to characterize effects of the supplementation protocols on hydration, blood pressure, body mass, and running economy. Eight trained males (age = 22 ± 3 y, V̇O2max = 66.4 ± 4.2 ml·kg-1·min-1) completed three identical weeks of run training (6 run·wk-1, 45 ± 6 min·run-1, 74 ± 5% HRR). After exercise, subjects consumed either, a beef nutritional supplement (beef jerky; [B]), a standard recovery drink (SRD), or SRD+B in a randomized counterbalanced design. Hydration status was assessed via urinary biomarkers and body mass. No main effects of treatment were observed for 24 hr urine volume (SRD, 1.7 ± 0.5; B, 1.8 ± 0.6; SRD+B, 1.4 ± 0.4 L·d-1), urine specific gravity (1.016 ± 0.005, 1.018 ± 0.006, 1.017 ± 0.006) or body mass (68.4 ± 8.2, 68.3 ± 7.7, 68.2 ± 8.1 kg). No main effect of treatment existed for sodium intake—loss (-713 ± 1486; -973 ± 1123; -980 ± 1220 mg·d-1). Mean arterial pressure (81.0 ± 4.6, 81.1 ± 7.3, 83.8 ± 5.4 mm Hg) and average exercise running economy (V̇O2: SRD, 47.9 ± 3.2; B, 47.2 ± 2.6; SRD+B, 46.2 ± 3.4 ml·kg-1·min-1) was not affected. Urinary sodium excretion accounted for the daily sodium intake due to the beef nutritional supplement. Findings suggest the commercial beef snack is a viable recovery supplement following endurance exercise without concern for hydration status, performance decrements, or cardiovascular consequences.

scholarly journals OR-055 Effect of whey protein on rehydration after exercise

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Lantian Zhang ◽  
Chenge Dang ◽  
Chunyan Xu
Keyword(s):  
Specific Gravity ◽  
Whey Protein ◽  
Body Mass ◽  
Intermittent Exercise ◽  
Urine Volume ◽  
Urine Osmolality ◽  
The Body ◽  
Urine Specific Gravity ◽  
Moderate Intensity ◽  
Exercise Induced

Objective The purpose of this study is to determine the effects of a rehydration solution containing whey protein on fluid balance after exercise-induced dehydration.The ACSM Sports Guide recommends that healthy adults exercise moderate-intensity aerobic exercise for 30 minutes a day.This type of exercise can dehydrate the body by about 1%.Dehydration 1% affects exercise capacity and performance.The purpose of this study was to exercise-induced dehydration of sports drinks containing whey protein. Methods Twelve college students ( 20 ± 2 years, 169.9 ± 8.1 cm, 63.3 ± 13 kg) participated. Participants reduced body mass by (0.67±0.33) after intermittent exercise and re-hydrated with a volume of drink in liter equivalent to 1.5 times their body mass loss in kilograms of a solution of 4 kinds of drinks：Distilled water(trial C), carbohydrate-electrolyte(trail D), carbohydrate-electrolyte-low whey protein(trial LWP) and carbohydrate-electrolyte-high whey protein(trail HWP). Solutions were matched for carbohydrate and electrolyte content in trail D、LWP and HWP. Trials were administered in a random, counterbalanced, crossover design, with subjects blinded as to which drink they consumed during each trial.  Each participant completed 4 experimental trials, which were separated by at least one week. Urine samples were collected before and after exercise (immediately, 40、80、120、160minutes later). Urine volume, drink retention, urine osmolality and urine specific gravity were tested. Drink retention was calculated as difference between the volume of drink ingested and urine produced. Results 1.Total cumulative urine output after exercise was not different between each of the four groups(C:1002 ±102mL;D:;LWP: ;HWP:，p>0.5 )； 2. During the study, drink retention of trail LWP is the highest(80.3±11.2%), but there was not different between each of the four groups(C: 70.5±20.6%;D:70.7±17.9% ;HWP: 75.0±12.4%， p>0.5). 3. At the 40th minute after exercise, the urine specific gravity of the D was significantly lower than that of the LWP(1.020±0.006 vs 1.028±0.003, p=0.020), and the urine specific gravity of the LWP at 120 minutes after exercise significantly higher than the D (1.018 ± 0.003 vs 1.021 ± 0.007, p = 0.006). Conclusions When the amount of dehydration after exercise is 1%-2%, each kind of the drinks in the study is useful for rehydration， and the addition of whey protein does not increase rehydration.

scholarly journals Effect of milk protein addition to a carbohydrate–electrolyte rehydration solution ingested after exercise in the heat

2010 ◽  
Vol 105 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Lewis J. James ◽  
David Clayton ◽  
Gethin H. Evans
Keyword(s):  
Body Mass ◽  
Milk Protein ◽  
Intermittent Exercise ◽  
Fluid Retention ◽  
Whole Body ◽  
Protein Solution ◽  
Before And After ◽  
K Concentration ◽  
Exercise Induced ◽  
Carbohydrate Solution

The present study examined the effects of milk protein on rehydration after exercise in the heat, via the comparison of energy- and electrolyte content-matched carbohydrate and carbohydrate–milk protein solutions. Eight male subjects lost 1·9 (sd 0·2) % of their body mass by intermittent exercise in the heat and rehydrated with 150 % of their body mass loss with either a 65 g/l carbohydrate solution (trial C) or a 40 g/l carbohydrate, 25 g/l milk protein solution (trial CP). Urine samples were collected before and after exercise and for 4 h after rehydration. Total cumulative urine output after rehydration was greater for trial C (1212 (sd 310) ml) than for trial CP (931 (sd 254) ml) (P < 0·05), and total fluid retention over the study was greater after ingestion of drink CP (55 (sd 12) %) than that after ingestion of drink C (43 (sd 15) %) (P < 0·05). At the end of the study period, whole body net fluid balance (P < 0·05) was less negative for trial CP ( − 0·26 (sd 0·27) litres) than for trial C ( − 0·52 (sd 0·30) litres), and although net negative for both the trials, it was only significantly negative after ingestion of drink C (P < 0·05). The results of the present study suggest that when matched for energy density and fat content, as well as for Na and K concentration, and when ingested after exercise-induced dehydration, a carbohydrate–milk protein solution is better retained than a carbohydrate solution. These results suggest that gram-for-gram, milk protein is more effective at augmenting fluid retention than carbohydrate.

Variability of Body Mass and Urine Specific Gravity in Elite Male Field Hockey Players During a Pre-Olympic Training Camp

2019 ◽  
Vol 29 (1) ◽  
pp. 46-50 ◽  
Author(s):  
Jason D. Vescovi ◽  
Greig Watson
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Fluid Replacement ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Intraindividual Variation ◽  
Male Athletes ◽  
Training Camp ◽  
Hockey Players ◽  
Before And After

This field-based observational study was designed to examine the intraindividual variation of first morning body mass and urine specific gravity (Usg) in male hockey players (n = 22) during a 10-day training camp. It was also designed to evaluate the prevalence and interrelationship of morning hypohydration and postmatch dehydration using Usg and changes in body mass, respectively. Body mass and Usg were measured upon waking; body mass was also measured before and after matches. Individual means, SD, and coefficient of variation (CV) were calculated for morning body mass and Usg using 3, 6, and 8 days. Daily prevalence for euhydration and postmatch dehydration using morning Usg (<1.020) and changes in body mass (>−2%), respectively, were determined. Measurement of morning body mass and Usg for 3 days had low variability (CV < 1%) with no improvement at 6 or 8 days. Between 36% and 73% of players were considered euhydrated based on morning Usg. Postmatch body mass was reduced >1% in 50–85% of players, with up to 40% experiencing changes >−2%. Postmatch changes in body mass were unrelated to Usg the subsequent morning. These outcomes can be helpful in establishing criteria for detecting meaningful changes in morning body mass and Usg in similar settings, helping to monitor hydration status in elite male athletes. Despite ample fluid availability and consumption, many players experienced hypohydration and dehydration during the camp, indicating that careful monitoring and an individual fluid replacement approach are warranted in these environments.

Human Hydration Indices: Acute and Longitudinal Reference Values

2010 ◽  
Vol 20 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Lawrence E. Armstrong ◽  
Amy C. Pumerantz ◽  
Kelly A. Fiala ◽  
Melissa W. Roti ◽  
Stavros A. Kavouras ◽  
...  
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Reference Values ◽  
Fluid Intake ◽  
Pure Water ◽  
Urine Volume ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Total Fluid Intake ◽  
Free Living

It is difficult to describe hydration status and hydration extremes because fluid intakes and excretion patterns of free-living individuals are poorly documented and regulation of human water balance is complex and dynamic. This investigation provided reference values for euhydration (i.e., body mass, daily fluid intake, serum osmolality; M ± SD); it also compared urinary indices in initial morning samples and 24-hr collections. Five observations of 59 healthy, active men (age 22 ± 3 yr, body mass 75.1 ± 7.9 kg) occurred during a 12-d period. Participants maintained detailed records of daily food and fluid intake and exercise. Results indicated that the mean total fluid intake in beverages, pure water, and solid foods was >2.1 L/24 hr (range 1.382–3.261, 95% confidence interval 0.970–3.778 L/24 hr); mean urine volume was >1.3 L/24 hr (0.875–2.250 and 0.675–3.000 L/24 hr); mean urine specific gravity was >1.018 (1.011–1.027 and 1.009–1.030); and mean urine color was ≥4 (4–6 and 2–7). However, these men rarely (0–2% of measurements) achieved a urine specific gravity below 1.010 or color of 1. The first morning urine sample was more concentrated than the 24-h urine collection, likely because fluids were not consumed overnight. Furthermore, urine specific gravity and osmolality were strongly correlated (r2 = .81–.91, p < .001) in both morning and 24-hr collections. These findings provide euhydration reference values and hydration extremes for 7 commonly used indices in free-living, healthy, active men who were not exercising in a hot environment or training strenuously.

Novel hydration assessment techniques employing thirst and a water intake challenge in healthy men

2014 ◽  
Vol 39 (2) ◽  
pp. 138-144 ◽  
Author(s):  
Lawrence E. Armstrong ◽  
Matthew S. Ganio ◽  
Jennifer F. Klau ◽  
Evan C. Johnson ◽  
Douglas J. Casa ◽  
...  
Keyword(s):  
Body Mass ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Fluid Replacement ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Healthy Men ◽  
Hydration State ◽  
Assessment Techniques ◽  
Hydration Assessment

Exploring novel hydration indices is important because no human biomarker has been shown to be incontrovertibly valid in all life situations. The present investigation was designed to identify inexpensive, nontechnical methods to use when self-assessing hydration status. This investigation evaluated the validity and efficacy of 2 novel techniques (i.e., thirst sensation and urine volume) to assess hydration state of 29 active men (mean ± SD; age, 23 ± 4 years; body mass, 76.02 ± 11.94 kg) at rest. Eight combinations of 4 water challenges (4.8, 9.3, 11.0, or 14 mL·kg−1) and 2 hydration states (mildly hypohydrated (HY), –2.0%; euhydrated (EU), –0.2% body mass) were employed. First, thirst was linearly related to body water loss, and ratings of thirst distinguished HY from EU (p < 0.001) subsequent to 19 h of controlled food and fluid intake. Second, measurements of urine volume 60 min after consuming a water bolus (11.0 or 14 mL·kg−1) were strongly and inversely correlated with entering hydration state, assessed by urine specific gravity (r2 = 0.76, p < 0.0001) and urine osmolality (r2 = 0.77, p < 0.0001). We concluded that healthy men can employ simple measurements of morning thirst sensation and urine volume to identify the presence of mild hypohydration and to guide fluid replacement. These 2 techniques are relevant because HY (–2% body mass) is the approximate threshold for the onset of thirst, reduced endurance exercise performance, and decrements of working memory and mood.

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