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 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 (< 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.

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.

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.

scholarly journals Neuronal (pro)renin receptor regulates deoxycorticosterone-induced sodium intake

2018 ◽  
Vol 50 (10) ◽  
pp. 904-912 ◽  
Author(s):  
Fatima Trebak ◽  
Wencheng Li ◽  
Yumei Feng
Keyword(s):  
Sodium Intake ◽  
Renin Angiotensin System ◽  
Urinary Sodium Excretion ◽  
Urinary Sodium ◽  
Sodium Balance ◽  
Total Fluid Intake ◽  
Sodium Deficiency ◽  
Sodium Appetite ◽  
The Central Nervous System ◽  
Salt Sensitive Hypertension

Increased sodium appetite is a physiological response to sodium deficiency; however, it has also been implicated in disease conditions such as congestive heart failure, kidney failure, and salt-sensitive hypertension. The central nervous system is the major regulator of sodium appetite and intake behavior; however, the neural mechanisms underlying this behavior remain incompletely understood. Here, we investigated the involvement of the (pro)renin receptor (PRR), a component of the brain renin-angiotensin system, in the regulation of sodium intake in a neuron-specific PRR knockout (PRRKO) mouse model generated previously in our laboratory. Sodium intake following deoxycorticosterone (DOCA) stimulation was tested by assessing the preference of mice for 0.9% saline or regular water in single-animal metabolic cages. Blood pressure was monitored in conscious, freely moving mice by a telemetry system. We found that saline intake and total fluid intake were significantly reduced in PRRKO mice following DOCA treatment compared with that in wild-type (WT) mice, whereas regular water intake was similar between the genotypes. Sodium preference and total sodium intake were significantly reduced in PRRKO mice compared with WT mice. PRRKO mice also excreted less urine and urinary sodium compared with WT mice following DOCA treatment, whereas potassium excretion was similar between the two groups. Finally, we found that the sodium balance, calculated by subtracting urinary sodium excretion from sodium intake, was greater in WT mice than in PRRKO mice. Collectively, these findings suggest that the neuronal PRR plays a regulatory role in DOCA-induced sodium intake.

Steady-state arterial pressure-urinary output relationships during ovine pregnancy

1992 ◽  
Vol 263 (5) ◽  
pp. R1141-R1146
Author(s):  
E. W. Quillen ◽  
B. S. Nuwayhid
Keyword(s):  
Renal Function ◽  
Steady State ◽  
Arterial Pressure ◽  
Sodium Intake ◽  
Control Level ◽  
Urine Volume ◽  
Urinary Sodium Excretion ◽  
Pregnant Sheep ◽  
Plasma Angiotensin ◽  
Steady State Levels

To determine the effects of long-term changes in sodium intake on mean arterial pressure (MAP) regulation during pregnancy, nonpregnant (n = 16) and 110- to 140-day pregnant (n = 13) ewes received total daily sodium intakes of 10, 30, 100, 400, and 1,200 mmol for 7 days. The sheep were housed in metabolism cages and MAP was monitored 24 h/day. Urinary sodium excretion (UNaV) followed changes in sodium intake, with steady-state levels being achieved with similar degrees of rapidity (2-3 days) in nonpregnant and pregnant sheep. At 10 mmol/day sodium intake, MAP was lower (79 +/- 1 vs. 82 +/- 2 mmHg; P < 0.01) and water intake (2,275 +/- 494 vs. 3,286 +/- 725 ml/day; P < 0.001) and 24-h urine volume (1,454 +/- 279 vs. 2,299 +/- 496 ml/day; P < 0.01) were greater in pregnant sheep. All of these variables exhibited direct relationships with increases in sodium intake. Plasma angiotensin II (pANG II) was increased in pregnancy (10.6 +/- 1.6 vs. 24.5 +/- 6.3 pg/ml; P < 0.001) at 10 mmol/day. Elevation of sodium intake suppressed pANG II to minimal levels in nonpregnant sheep, but to only 25% of the control level in pregnant sheep. During pregnancy, the renal function curve representing the steady-state MAP-UNaV relationship was shifted to lower MAP setpoint, but the sodium sensitivity of MAP was unchanged. Also, the inverse relationship of sodium intake and pANG II was blunted, suggesting a reduced role for ANG II in the maintenance of renal function during pregnancy.

scholarly journals Dietary Intake, Hydration Status, and Body Composition of Three Belgian Military Groups

2020 ◽  
Vol 185 (7-8) ◽  
pp. e1175-e1182
Author(s):  
William De Bry ◽  
Patrick Mullie ◽  
Eva D’Hondt ◽  
Peter Clarys
Keyword(s):  
Body Composition ◽  
Dietary Intake ◽  
Body Mass ◽  
Fat Mass ◽  
Military Training ◽  
Weather Conditions ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Dietary Intakes ◽  
Negative Consequences

Abstract Introduction Malnutrition, suboptimal hydration, and inadequate body composition can have negative consequences on soldiers’ performance and health. A recent consensus statement concerning “soldiers’ physical performance” points to the scarcity of data in specific military populations. Therefore, the aim of the present study was to assess and compare dietary intake, hydration status, and body composition of three military groups during their specific military training. Materials and Methods Eighty-five soldiers (ie, 21 in a qualification course to join the Special Forces [SF], 22 Infantrymen [Chasseurs Ardennais, CA], and 42 Recruits [REs]) participated in this 3- to 4-day study. Body mass was assessed before and after each study period. All soldiers self-reported their dietary intakes, from which energy and macronutrient intakes were calculated. In addition, their morning urine samples were collected daily to assess urine specific gravity (USG) as a measure of hydration status. Fat mass was estimated at the end of the study using bioelectrical impedance analysis. Results All groups lost significant amounts of body mass (ie, mean losses ranging between 1.3 and 1.7 kg). Macronutrient intakes were not fully met in respect to the recommendations. Most notably, REs’ fat intake was high (ie, 42.3 [±1.6] energy percent [E%]), while their carbohydrate intake was low (ie, 44.5 [±2.1] E%). Furthermore, saturated fat intakes were high among all groups (ie, group means ranging between 13.6 and 21.4 E%). USG values indicated suboptimal hydration status was prevalent in all groups. Most noteworthy, for SF, only 5.4% of the USG values indicated optimal hydration. The average fat mass (%) for SF, CA, and RE was 11.2 (±3.1), 18.8 (±5.1), and 19.4 (±5.0), respectively. Conclusion The present study showed that military men are not always adequately fed nor hydrated. These issues should be resolved by creating nutritional packages, and individual dietary and hydration strategies, all in function of military planning and weather conditions.

Hydration status of Greco-Roman wrestlers in an authentic precompetition situation

2013 ◽  
Vol 38 (6) ◽  
pp. 621-625 ◽  
Author(s):  
Vahur Ööpik ◽  
Saima Timpmann ◽  
Andres Burk ◽  
Innar Hannus
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Urine Osmolality ◽  
Mass Gain ◽  
The Body ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Greco Roman ◽  
Reduced Body ◽  
Body Mass Gain

We assessed the urinary indexes of hydration status of Greco-Roman wrestlers in an authentic precompetition situation at the time of official weigh-in (OWI). A total of 51 of 89 wrestlers competing in the Estonian Championship in 2009 donated a urine sample. Questionnaire responses revealed that 27 wrestlers (body mass losers (BMLs)) reduced body mass before the competition, whereas 24 wrestlers (those who do not lose body mass (n-BMLs)) did not. In 42 wrestlers, values of urine specific gravity ≥1.020 and urine osmolality ≥700 mOsmol·kg−1 revealed a hypohydrated status. The prevalence of hypohydration in the BMLs (96%) was higher than in the n-BMLs (67%) (χ2 = 7.68; p < 0.05). The prevalence of serious hypohydration (urine specific gravity >1.030) was 5.3 times greater (χ2 = 8.32; p < 0.05) in the BMLs than in the n-BMLs. In the BMLs, the extent of body mass gain during the 16-h recovery (2.5 ± 1.2 kg) was associated (r = 0.764; p < 0.05) with self-reported precompetition body mass loss (4.3 ± 2.0 kg) and exceeded the body mass gain observed in the n-BMLs (0.7 ± 1.2 kg; p < 0.05). We conclude that hypohydration is prevalent among Greco-Roman wrestlers at the time of OWI. The prevalence of hypohydration and serious hypohydration is especially high among wrestlers who are accustomed to reducing body mass before competition. These results suggest that an effective rehydration strategy is needed for Olympic-style wrestlers, and that changes in wrestling rules should be considered to reduce the prevalence of harmful body mass management behaviours.

Sweat rate, salt loss, and fluid intake during an intense on-ice practice in elite Canadian male junior hockey players

2008 ◽  
Vol 33 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Matthew S. Palmer ◽  
Lawrence L. Spriet
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Sodium Concentration ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Body Mass Loss ◽  
Hockey Players ◽  
Sodium Loss

Previous research in many sports suggests that losing ~1%–2% body mass through sweating impairs athletic performance. Elite-level hockey involves high-intensity bursts of skating, arena temperatures are >10 °C, and players wear protective equipment, all of which promote sweating. This study examined the pre-practice hydration, on-ice fluid intake, and sweat and sodium losses of 44 candidates for Canada’s junior men’s hockey team (mean ± SE age, 18.4 ± 0.1 y; height, 184.8 ± 0.9 cm; mass, 89.9 ± 1.1 kg). Players were studied in groups of 10–12 during 4 intense 1 h practices (13.9 °C, 66% relative humidity) on 1 day. Hydration status was estimated by measuring urine specific gravity (USG). Sweat rate was calculated from body mass changes and fluid intake. Sweat sodium concentration ([Na]) was analyzed in forehead sweat patch samples and used with sweat rate to estimate sodium loss. Over 50% of players began practice mildly hypohydrated (USG > 1.020). Sweat rate during practice was 1.8 ± 0.1 L·h–1 and players replaced 58% (1.0 ± 0.1 L·h–1) of the sweat lost. Body mass loss averaged 0.8% ± 0.1%, but 1/3 of players lost more than 1%. Sweat [Na] was 54.2 ± 2.4 mmol·L–1 and sodium loss averaged 2.26 ± 0.17 g during practice. Players drank only water during practice and replaced no sodium. In summary, elite junior hockey players incurred large sweat and sodium losses during an intense practice, but 2/3 of players drank enough to minimize body mass loss. However, 1/3 of players lost more than 1% body mass despite ready access to fluid and numerous drinking opportunities from the coaches.

Effect of Indomethacin on Blood Pressure in the Normotensive Unanaesthetized Rabbit: Possible Relation to Prostaglandin Synthesis Inhibition

1979 ◽  
Vol 57 (4) ◽  
pp. 359-365 ◽  
Author(s):  
J. Colina-Chourio ◽  
J. C. McGiff ◽  
A. Nasjletti
Keyword(s):  
Blood Pressure ◽  
Sodium Intake ◽  
Control Period ◽  
Urine Volume ◽  
Urinary Sodium Excretion ◽  
Prostaglandin Synthesis ◽  
Endogenous Prostaglandins ◽  
Cumulative Difference ◽  
Aortic Blood Pressure ◽  
Regulation Of Blood Pressure

1. To test the hypothesis that endogenous prostaglandins contribute to the regulation of blood pressure, we studied the effect of an inhibitor of prostaglandin synthesis, indomethacin, on mean aortic blood pressure in the normotensive, unanaesthetized rabbit. 2. Daily administration of indomethacin at 42 μmol/kg subcutaneously, but not of vehicle only, for 14 consecutive days, elevated the average mean arterial pressure in seven rabbits from 88 ± 3 mmHg on the last day of the control period to 105 + 3 mmHg (P < 0·01) and 107 ± 2 mmHg (P < 0·01) on days 6 and 14 of indomethacin treatment respectively, and reduced the urinary excretion of prostaglandin-like substance from 1·06 ± 0·26 to 0·17 ± 0·05 nmol of prostaglandin E2 equivalents/ day (P < 0·05; n = 5). Neither indomethacin nor the vehicle affected the intake of water, the 24 h urine volume, the cumulative difference between sodium intake and urinary sodium excretion, or the plasma volume. 3. The results of the study are compatible with the hypothesis that one or more prostaglandins contribute to maintain normotension in the rabbit and that reduction in prostaglandin biosynthesis may cause blood pressure to rise.

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