scholarly journals Effect of Drink Carbohydrate Content on Postexercise Gastric Emptying, Rehydration, and the Calculation of Net Fluid Balance

2014 ◽  
Vol 24 (1) ◽  
pp. 79-89 ◽  
Author(s):  
David J. Clayton ◽  
Gethin H. Evans ◽  
Lewis J. James
Keyword(s):  
Gastric Emptying ◽  
Body Mass ◽  
Fluid Balance ◽  
Sampling Period ◽  
Body Mass Loss ◽  
Hypertonic Glucose ◽  
The Hours ◽  
Blood And Urine Samples ◽  
Exercise Induced ◽  
Test Drink

The purpose of this study was to examine the gastric emptying and rehydration effects of hypotonic and hypertonic glucose-electrolyte drinks after exercise-induced dehydration. Eight healthy males lost ~1.8% body mass by intermittent cycling and rehydrated (150% of body mass loss) with a hypotonic 2% (2% trial) or a hypertonic 10% (10% trial) glucose-electrolyte drink over 60 min. Blood and urine samples were taken at preexercise, postexercise, and 60, 120, 180, and 240 min postexercise. Gastric and test drink volume were determined 15, 30, 45, 60, 90, and 120 min postexercise. At the end of the gastric sampling period 0.3% (2% trial) and 42.1% (10% trial; p < .001) of the drinks remained in the stomach. Plasma volume was lower (p < .01) and serum osmolality was greater (p < .001) at 60 and 120 min during the 10% trial. At 240 min, 52% (2% trial) and 64% (10% trial; p < .001) of the drinks were retained. Net fluid balance was greater from 120 min during the 10% trial (p < .001). When net fluid balance was corrected for the volume of fluid in the stomach, it was greater at 60 and 120 min during the 2% trial (p < .001). These results suggest that the reduced urine output following ingestion of a hypertonic rehydration drink might be mediated by a slower rate of gastric emptying, but the slow gastric emptying of such solutions makes rehydration efficiency difficult to determine in the hours immediately after drinking, compromising the calculation of net fluid balance.

Restoration of fluid balance after exercise-induced dehydration: effects of alcohol consumption

1997 ◽  
Vol 83 (4) ◽  
pp. 1152-1158 ◽  
Author(s):  
Susan M. Shirreffs ◽  
Ronald J. Maughan
Keyword(s):  
Alcohol Consumption ◽  
Body Mass ◽  
Fluid Balance ◽  
Inverse Function ◽  
Recovery Process ◽  
Electrolyte Balance ◽  
Dilute Solution ◽  
Loss Peak ◽  
Body Mass Loss ◽  
Exercise Induced

Shirreffs, Susan M., and Ronald J Maughan. Restoration of fluid balance after exercise-induced dehydration: effects of alcohol consumption. J. Appl. Physiol. 83(4): 1152–1158, 1997.—The effect of alcohol consumption on the restoration of fluid and electrolyte balance after exercise-induced dehydration [2.01 ± 0.10% (SD) of body mass] was investigated. Drinks containing 0, 1, 2, and 4% alcohol were consumed over 60 min beginning 30 min after the end of exercise; a different beverage was consumed in each of four trials. The volume consumed (2,212 ± 153 ml) was equivalent to 150% of body mass loss. Peak urine flow rate occurred later ( P = 0.024) with the 4% beverage. The total volume of urine produced over the 6 h after rehydration, although not different between trials ( P = 0.307), tended to increase as the quantity of alcohol ingested increased. The increase in blood ( P = 0.013) and plasma ( P = 0.050) volume with rehydration was slower when the 4% beverage was consumed and did not increase to values significantly greater than the dehydrated level ( P = 0.013 and P = 0.050 for blood volume and plasma volume, respectively); generally, the increase was an inverse function of the quantity of alcohol consumed. These results suggest that alcohol has a negligible diuretic effect when consumed in dilute solution after a moderate level of hypohydration induced by exercise in the heat. There appears to be no difference in recovery from dehydration whether the rehydration beverage is alcohol free or contains up to 2% alcohol, but drinks containing 4% alcohol tend to delay the recovery process.

Sex differences in the physiological responses to exercise-induced dehydration: Consequences and mechanisms?

2021 ◽  
Author(s):  
Kate Aiko Wickham ◽  
Devin G. McCarthy ◽  
Lawrence L. Spriet ◽  
Stephen S. Cheung
Keyword(s):  
Sex Differences ◽  
Mass Loss ◽  
Body Mass ◽  
Sweat Gland ◽  
Body Water ◽  
Physiological Strain ◽  
Body Mass Loss ◽  
Cardiac Strain ◽  
Exercise Onset ◽  
Exercise Induced

Physiological strain during exercise is increased by mild dehydration (~1-3% body mass loss). This response may be sex-dependent but there are no direct comparative data in this regard. This review aimed to develop a framework for future research by exploring the potential impact of sex on thermoregulatory and cardiac strain associated with exercise-induced dehydration. Sex-based comparisons were achieved by comparing trends from studies that implemented similar experimental protocols but recruited males and females separately. This revealed a higher core temperature (Tc) in response to exercise-induced dehydration in both sexes, however it seemingly occurred at a lower percent body mass loss in females. Although less clear, similar trends existed for cardiac strain. The average female may have a lower body water volume per body mass compared to males, and therefore the same % body mass loss between the sexes may represent a larger portion of total body water in females potentially posing a greater physiological strain. Additionally, the rate which Tc increases at exercise onset might be faster in females and induce a greater thermoregulatory challenge earlier into exercise. The Tc response at exercise onset is associated with lower sweating rates in females, which is commonly attributed to sex-differences in metabolic heat production. However, a reduced sweat gland sensitivity to stimuli, lower fluid output per sweat gland, and sex hormones promoting fluid retention in females may also contribute. In conclusion, the limited evidence suggests sex-based differences exist in thermoregulatory and cardiac strain associated with exercise-induced dehydration, and this warrants future investigations.

Volume repletion after exercise-induced volume depletion in humans: replacement of water and sodium losses

1998 ◽  
Vol 274 (5) ◽  
pp. F868-F875 ◽  
Author(s):  
Susan M. Shirreffs ◽  
Ronald J. Maughan
Keyword(s):  
Body Mass ◽  
Fluid Balance ◽  
Intermittent Exercise ◽  
Sodium Intake ◽  
Recovery Period ◽  
Whole Body ◽  
Sodium Balance ◽  
Volume Depletion ◽  
Urine Production ◽  
Exercise Induced

Sodium and water loss during, and replacement after, exercise-induced volume depletion was investigated in six volunteers volume depleted by 1.89 ± 0.17% (SD) of body mass by intermittent exercise in a warm, humid environment. Subjects exercised in a large, open plastic bag, allowing collection of all sweat secreted during exercise. For over 60 min beginning 40 min after the end of exercise, subjects ingested drinks containing 0, 25, 50, or 100 mmol/l sodium ( trials 0, 25, 50, and 100) in a volume (ml) equivalent to 150% of the mass lost (g) by volume depletion. Body mass loss and sweat electrolyte (Na+, K+, and Cl−) loss were the same on each trial. The measured sweat sodium concentration was 49.2 ± 18.5 mmol/l, and the total loss (63.9 ± 38.7 mmol) was greater than that ingested on trials 0 and 25. Urine production over the 6-h recovery period was inversely related to the amount of sodium ingested. Subjects were in whole body negative sodium balance on trials 0 (−104 ± 48 mmol) and 25 (−65 ± 30 mmol) and essentially in balance on trial 50(−13 ± 29 mmol) but were in positive sodium balance on trial 100 (75 ± 40 mmol). Only on trial 100 were subjects in positive fluid balance at the end of the study. There was a large urinary loss of potassium over the recovery period on trial 100, despite a negligible intake during volume repletion. These results confirm the importance of replacement of sodium as well as water for volume repletion after sweat loss. The sodium intake on trial 100 was appropriate for acute fluid balance restoration, but its consequences for potassium levels must be considered to be undesirable in terms of whole body electrolyte homeostasis for anything other than the short term.

scholarly journals Comparing the rehydration potential of different milk-based drinks to a carbohydrate–electrolyte beverage

2014 ◽  
Vol 39 (12) ◽  
pp. 1366-1372 ◽  
Author(s):  
Ben Desbrow ◽  
Sarah Jansen ◽  
Abby Barrett ◽  
Michael D. Leveritt ◽  
Christopher Irwin
Keyword(s):  
Body Mass ◽  
Cow’S Milk ◽  
Soy Milk ◽  
Additional Energy ◽  
Liquid Meal ◽  
Cow's Milk ◽  
Sports Drinks ◽  
Traditional Sports ◽  
Blood And Urine Samples ◽  
Exercise Induced

The aim of this study was to compare the rehydration potential of a carbohydrate–electrolyte beverage with several varieties of milk following exercise-induced fluid losses. Fifteen male participants (age 24.9 ± 5.5 years, height 179.3 ± 4.9 cm, body mass 75.8 ± 6.6 kg (mean ± SD)) lost 2.0% ± 0.2% body mass through intermittent cycling before consuming a different beverage on 4 separate occasions. Drinks included cow’s milk (286 kJ·100 mL−1), soy milk (273 kJ·100 mL−1), a milk-based liquid meal supplement (Sustagen Sport (Nestle); 417 kJ·100 mL−1), and a sports drink (Powerade (Coca Cola Ltd); 129 kJ·100 mL−1). Beverages were consumed over 1 h in volumes equivalent to 150% of body mass loss. Body mass, blood and urine samples, and measures of gastrointestinal tolerance were obtained before and hourly for 4 h after beverage consumption. Net body mass at the conclusion of each trial was significantly less with Powerade (–1.37 ± 0.3 kg) than with cow’s milk (–0.92 ± 0.48 kg), soy milk (–0.78 ± 0.37 kg), and Sustagen Sport (–0.48 ± 0.39 kg). Net body mass was also significantly greater for Sustagen Sport compared with cow’s milk trials, but not soy milk. Upon completion of trials, the percentage of beverage retained was Sustagen Sport 65.1% ± 14.7%, soy milk 46.9% ± 19.9%, cow’s milk 40.0% ± 24.9%, and Powerade 16.6% ± 16.5%. Changes in plasma volume and electrolytes were unaffected by drink treatment. Subjective ratings of bloating and fullness were higher during all milk trials compared with Powerade whereas ratings of overall thirst were not different between beverages. Milk-based drinks are more effective rehydration options compared with traditional sports drinks. The additional energy, protein, and sodium in a milk-based liquid meal supplement facilitate superior fluid recovery following exercise.

scholarly journals Impact of Exercise-induced Dehydration on Perceived Exertion During Endurance Exercise: A Systematic Review with Meta-analysis

2021 ◽  
Author(s):  
Thomas A Deshayes ◽  
Timothee Pancrate ◽  
Eric DB Goulet
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Endurance Exercise ◽  
Perceived Exertion ◽  
Meta Analysis ◽  
Exercise Adherence ◽  
Rating Of Perceived Exertion ◽  
Body Mass Loss ◽  
Exercise Induced ◽  
The Impact

Understanding the impact of stressors on the rating of perceived exertion (RPE) is relevant from a performance and exercise adherence/participation standpoint. Athletes and recreationally active individuals dehydrate during exercise. No attempt has been made to systematically determine the impact of exercise-induced dehydration (EID) on RPE. The present meta-analysis aimed to determine the effect of EID on RPE during endurance exercise and examine the moderating effect of potential confounders using a meta-analytical approach. Data analyses were performed on raw RPE values using random-effects models weighted mean effect summaries and meta-regressions with robust standard errors, and with a practical meaningful effect set at 1 point difference between euhydration (EUH) and EID. Only controlled crossover studies measuring RPE with a Borg scale in healthy adults performing ≥ 30 min of continuous endurance exercise while dehydrating or drinking to maintain EUH were included. Sixteen studies were included, representing 147 individuals. Mean body mass loss with EUH was 0.5 ± 0.4%, compared to 2.3 ± 0.5% with EID (range 1.7 to 3.1%). Within an EID of 0.5 to 3% body mass, a maximum difference in RPE of 0.81 points (95% CI: 0.36-1.27) was observed between conditions. A meta-regression revealed that RPE increases by 0.21 points for each 1% increase in EID (95% CI: 0.12-0.31). Humidity, ambient temperature and aerobic capacity did not alter the relationship between EID and RPE. Therefore, the effect of EID on RPE is unlikely to be practically meaningful until a body mass loss of at least 3%.

The Effect of Ad Libitum Consumption of a Milk-Based Liquid Meal Supplement vs. a Traditional Sports Drink on Fluid Balance After Exercise

2016 ◽  
Vol 26 (4) ◽  
pp. 347-355 ◽  
Author(s):  
Brenton J. Baguley ◽  
Jessica Zilujko ◽  
Michael D. Leveritt ◽  
Ben Desbrow ◽  
Christopher Irwin
Keyword(s):  
Body Mass ◽  
Fluid Balance ◽  
Urine Output ◽  
Moderate Intensity ◽  
Fluid Loss ◽  
Liquid Meal ◽  
Sports Drink ◽  
Gastrointestinal Tolerance ◽  
Ad Libitum ◽  
Exercise Induced

The aim of this study was to compare the effect of ad libitum intake of a milk-based liquid meal supplement against a carbohydrate-electrolyte sports drink following exercise induced fluid loss. Seven male participants (age 22.3 ± 3.4 years, height 179.3 ± 7.9 cm, body mass 74.3 ± 7.3 kg; mean ± SD) completed 4 separate trials and lost 1.89 ± 0.44% body mass through moderate intensity exercise in the laboratory. After exercise, participants consumed ad libitum over 2 h a milk-based liquid meal supplement (Sustagen Sport) on two of the trials (S1, S2) or a carbohydrate-electrolyte sports drink (Powerade) on two of the trials (P1, P2), with an additional 1 hr observational period. Measures of body mass, urine output, gastrointestinal tolerance and palatability were collected throughout the recovery period. Participants consumed significantly more Powerade than Sustagen Sport over the 2 h rehydration period (P1 = 2225 ± 888 ml, P2 = 2602 ± 1119 mL, S1 = 1375 ± 711 mL, S2 = 1447 ± 857 ml). Total urine output on both Sustagen trails was significantly lower than the second Powerade trial (P2 = 1447 ± 656 ml, S1 = 153 ± 62 ml, S2 = 182 ± 118 mL; p < .05) and trended toward being lower compared with the first Powerade trial (P1 = 1057 ± 699 ml vs. S1, p = .067 and vs. S2, p = .061). No significant differences in net fluid balance were observed between any of the drinks at the conclusion of each trial (P1 = −0.50 ±0. 46 kg, P2 = −0.40 ± 0.35 kg, S1 = −0.61 ± 0.74 kg, S2 = −0.45 ± 0.58 kg). Gastrointestinal tolerance and beverage palatability measures indicated Powerade to be preferred as a rehydration beverage. Ad libitum milk-based liquid meal supplement results in similar net fluid balance as a carbohydrate-electrolyte sports drink after exercise induced fluid loss.

scholarly journals Effect of caffeine ingestion on fluid balance during exercise in the heat and during recovery

2014 ◽  
Vol 26 (2) ◽  
pp. 43
Author(s):  
Yang Zhang ◽  
S J Carter ◽  
R E Schumacker ◽  
Y H Neggers ◽  
M D Curtner-Smith, ◽  
...  
Keyword(s):  
Mass Loss ◽  
Body Mass ◽  
Fluid Balance ◽  
Recovery Period ◽  
The Body ◽  
Body Mass Loss ◽  
Caffeine Ingestion ◽  
Hot Environment ◽  
Urine Production ◽  
Randomised Controlled

Background. The effect of ingestion of a common stimulant, caffeine, on fluid balance during exercise and recovery is not fully known. Objectives. To determine the effect of caffeine on fluid balance during exercise in the heat and during a 3-hour recovery period thereafter. Methods. In a randomised, controlled design, caffeine-naive participants (N=8) pedalled on a bike to achieve 2.5% baseline body mass loss in a hot environment in four separate conditions: with (C+) or without (C–) caffeine ingestion (6 mg/kg of body mass) prior to exercise, followed by (W+) or without (W–) 100% fluid replenishment (water) of the body mass loss during a 3-hour recovery period (yielding C+W+, C+W–, C–W+ and C–W–, respectively). Results. Mean (standard deviation) urine production was not different (p>0.05) regardless of rehydration status: 230 (162) mL (C+W–) v. 168 (77) mL (C–W–); and 713 (201) mL (C+W+) v. 634 (185) mL (C–W+). For the 3-hour recovery, caffeine ingestion caused higher hypohydration during rehydration conditions (p=0.02), but practically the mean difference in the loss of body mass was only 0.2 kg. Conclusion. In practical terms, there was no evidence that caffeine ingestion in moderation would impair fluid balance during prolonged exercise in the heat or during 3 hours of recovery.

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