Postexercise rehydration in man: the effects of carbohydrate content and osmolality of drinks ingested ad libitum

2009 ◽  
Vol 34 (4) ◽  
pp. 785-793 ◽  
Author(s):  
Gethin H. Evans ◽  
Susan M. Shirreffs ◽  
Ronald J. Maughan
Keyword(s):  
Fluid Balance ◽  
Fluid Intake ◽  
Intermittent Exercise ◽  
Recovery Period ◽  
Electrolyte Solutions ◽  
Carbohydrate Content ◽  
Whole Body ◽  
Total Fluid Intake ◽  
Before And After ◽  
Ad Libitum

The effectiveness of different carbohydrate solutions in restoring fluid balance in situations of voluntary fluid intake has not been examined previously. The effect of the carbohydrate content of drinks ingested after exercise was examined in 6 males and 3 females previously dehydrated by 1.99 ± 0.07% of body mass via intermittent exercise in the heat. Beginning 30 min after the cessation of exercise, subjects drank ad libitum for a period of 120 min. Drinks contained 31 mmol·L–1 Na+ as NaCl and either 0%, 2%, or 10% glucose with mean ± SD osmolalities of 74 ± 1, 188 ± 3, and 654 ± 4 mosm·kg–1, respectively. Blood and urine samples were collected before and after exercise, midway through rehydration, and throughout a 5 h recovery period. Total fluid intake was not different among trials (0%: 2258 ± 519 mL; 2%: 2539 ± 436 mL; 10%: 2173 ± 252 mL; p = 0.173). Urine output was also not different among trials (p = 0.160). No differences among trials were observed in net fluid balance or in the fraction of the ingested drink retained. In conclusion, in situations of voluntary fluid intake, hypertonic carbohydrate-electrolyte solutions are as effective as hypotonic carbohydrate-electrolyte solutions at restoring whole-body fluid balance.

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.

Sprint training increases human skeletal muscle Na(+)-K(+)-ATPase concentration and improves K+ regulation

1993 ◽  
Vol 75 (1) ◽  
pp. 173-180 ◽  
Author(s):  
M. J. McKenna ◽  
T. A. Schmidt ◽  
M. Hargreaves ◽  
L. Cameron ◽  
S. L. Skinner ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Intermittent Exercise ◽  
Recovery Period ◽  
Muscle Performance ◽  
Vastus Lateralis Muscle ◽  
Work Output ◽  
Sprint Training ◽  
Ouabain Binding ◽  
Before And After

This study investigated the effects of sprint training on muscle Na(+)-K(+)-adenosinetriphosphatase (ATPase) concentration, plasma [K+] regulation, muscle performance, and fatigue during severe intermittent exercise. Six untrained male subjects underwent intensive cycle-sprint training for 7 wk. Muscle biopsies were taken at rest from the vastus lateralis muscle before and after 7 wk of training and were assayed for Na(+)-K(+)-ATPase concentration using vanadate-facilitated [3H]ouabain binding to intact samples. Before and after the training period, subjects performed four maximal 30-s exercise bouts (EB) on a cycle ergometer, each separated by a 4-min recovery. Arterialized venous blood samples were drawn immediately before and after each sprint bout and were analyzed for plasma [K+]. The work output was significantly elevated (11%) across all four EBs after training. The muscle [3H]ouabain binding site concentration was significantly increased (16%) from 333 +/- 19 to 387 +/- 15 (SE) pmol/g wet wt after training but was unchanged in muscle obtained from three control subjects. Plasma [K+] rose by 1–2 mmol/l with each EB and declined rapidly by the end of each recovery period. The increases in plasma [K+] resulting from each EB were significantly lower (19%) after training. The ratios of rise in plasma [K+] relative to work output during each EB were also significantly lower (27%) after training. The increased muscle [3H]ouabain binding site concentration and the reduced ratio of rise in [K+] relative to work output with exercise are both consistent with improved plasma and skeletal muscle K+ regulation after sprint training.

scholarly journals Effect of a Padel Match on Biochemical and Haematological Parameters in Professional Players with Regard to Gender-Related Differences

2020 ◽  
Vol 12 (20) ◽  
pp. 8633
Author(s):  
Francisco Pradas ◽  
Alejandro García-Giménez ◽  
Víctor Toro-Román ◽  
Bernardino Javier Sánchez-Alcaraz ◽  
Nicolae Ochiana ◽  
...  
Keyword(s):  
Biochemical Parameters ◽  
Fluid Intake ◽  
Serum Concentrations ◽  
Protein Catabolism ◽  
Glutamic Oxaloacetic Transaminase ◽  
Before And After ◽  
Baseline Values ◽  
Ad Libitum ◽  
High Level ◽  
Match Effect

Haematological and biochemical parameters have not yet been analysed in professional padel players. The aim of this study was to determine the basal values of these parameters and to observe the effect of a simulated competition on them, including gender-related differences. A total of 14 male professional players (age: 28.2 ± 7.9 years), and 16 female professional players (age: 29.7 ± 3.7 years) participated in this study. Players were allowed to hydrate ad libitum during the matches. Haematological and biochemical values were obtained before and after a simulated competitive padel match. The men’s group showed higher baseline values in red blood cells, haematocrit, haemoglobin, urea, creatinine, uric acid, albumin, glutamic oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), lactate dehydrogenase (LDH) and creatine kinase (CK) (p < 0.01) than the women’s group. Attending to match effect, significant differences were obtained in urea, creatinine, CK and glucose (p < 0.05). Finally, the group x match interaction revealed significant differences in serum concentrations of sodium and chloride (p < 0.05). In conclusion, high-level padel matches provoke several changes in biochemical parameters related to muscle damage and protein catabolism. Recovery and fluid intake strategies could be added regarding gender. The results obtained could be due to the differences in the intensity and volume of the simulated competition.

scholarly journals Drinking to Thirst Versus Drinking Ad Libitum During Road Cycling

2014 ◽  
Vol 49 (5) ◽  
pp. 624-631 ◽  
Author(s):  
Lawrence E. Armstrong ◽  
Evan C. Johnson ◽  
Laura J. Kunces ◽  
Matthew S. Ganio ◽  
Daniel A. Judelson ◽  
...  
Keyword(s):  
Body Mass ◽  
Perceived Exertion ◽  
Fluid Intake ◽  
Thermal Sensation ◽  
Drinking Behavior ◽  
Total Fluid Intake ◽  
Finish Line ◽  
Road Cycling ◽  
Significant Difference ◽  
Ad Libitum

Context: The sensation of thirst is different from the complex behavior of drinking ad libitum. Rehydration recommendations to athletes differ, depending on the source, yet no previous researchers have systematically compared drinking to thirst (DTT) versus ad libitum drinking behavior (DAL). Objective: To compare 2 groups of trained cyclists (DTT and DAL) who had similar physical characteristics and training programs (P &gt; .05). The DTT group (n = 12, age = 47 ± 7 years) drank only when thirsty, whereas the DAL group (n = 12, age = 44 ± 7 years) consumed fluid ad libitum (ie, whenever and in whatever volume desired). Design: Cohort study. Setting: Road cycling (164 km) in the heat (36.1°C ± 6.5°C). Patients or Other Participants: Ultraendurance cyclists (4 women, 20 men). Intervention(s): We recorded measurements 1 day before the event, on event day before the start, at 3 roadside aid stations, at the finish line, and 1 day after the event. Main Outcome Measure(s): Body mass, urinary hydration indices, and food and fluids consumed. Results: No between-groups differences were seen on event day for total exercise time (DTT = 6.69 ± 0.89 hours, DAL = 6.66 ± 0.77 hours), urinary indices (specific gravity, color), body mass change (DTT = −2.22% ± 1.73%, DAL = −2.29% ± 1.62%), fluid intake (DTT = 5.63 ± 2.59 L/6.7 h, DAL = 6.04 ± 2.37 L/6.7 h), dietary energy intake, macronutrient intake, ratings of thirst (DTT start = 2 ± 1, DTT finish = 6 ± 1, DAL start = 2 ± 1, DAL finish = 6 ± 1), pain, perceived exertion, or thermal sensation. Total fluid intake on recovery day +1 was the primary significant difference (DAL = 5.13 ± 1.87 L/24 h, DTT = 3.13 ± 1.53 L/24 h, t18 = 2.59, P = .02). Conclusions: Observations on event day indicated that drinking to thirst and drinking ad libitum resulted in similar physiologic and perceptual outcomes. This suggests that specific instructions to “drink to thirst” were unnecessary. Indeed, if athletes drink ad libitum, they can focus on training and competition rather than being distracted by ongoing evaluation of thirst sensations.

Effect of Beverage Flavor on Body Hydration in Hong Kong Chinese Children Exercising in a Hot Environment

2014 ◽  
Vol 26 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Stephen Heung-Sang Wong ◽  
Feng-Hua Sun
Keyword(s):  
Intermittent Exercise ◽  
Latin Square ◽  
Rest Period ◽  
Chinese Children ◽  
Total Fluid Intake ◽  
Hot Environment ◽  
Humid Environment ◽  
Flavored Water ◽  
Ad Libitum ◽  
Body Fluid Balance

The purpose of the current study was to examine the effect of flavor on voluntary drinking and thermoregulatory responses in Chinese boys and girls exercising intermittently in a hot environment. Fourteen boys and girls (9 to 11 years old) performed four 3-hour intermittent exercise sessions (20-min walking sessions at 50% VO2peak followed by a 25-minute rest period) in a hot and humid environment (~30 °C ambient temperature and ~70% relative humidity). The participants consumed 1 of 4 beverages ad libitum in a randomized sequence by using a Latin-square principle: unflavored water (W), orange-flavored water (OF), lemon-flavored water (LF), and grape-flavored water (GF). No differences were observed in the total fluid intake (W vs. OF vs. LF vs. GF: Boys, 441 ± 114 vs. 493 ± 106 vs. 387 ± 83 vs. 568 ± 146 ml; Girls, 613 ± 131 vs. 923 ± 204 vs. 825 ± 157 vs. 790 ± 166 ml), urine and sweat output, and physiological perceptual variables among trials and between sexes. The results suggested that Chinese children can maintain body fluid balance while exercising moderately in a hot and humid environment by ad libitum drinking. The flavor of the beverages had no impact on the voluntary drinking and the state of hydration in the current study.

scholarly journals Fluid Balance and Sodium Losses During Indoor Tennis Match Play

2011 ◽  
Vol 21 (6) ◽  
pp. 492-500 ◽  
Author(s):  
Matthew J.E. Lott ◽  
Stuart D.R. Galloway
Keyword(s):  
Heart Rate ◽  
Body Mass ◽  
Fluid Balance ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Fluid Replacement ◽  
Whole Body ◽  
Electrolyte Balance ◽  
Match Play ◽  
Tennis Match

This study assessed fluid balance, sodium losses, and effort intensity during indoor tennis match play (17 ± 2 °C, 42% ± 9% relative humidity) over a mean match duration of 68.1 ± 12.8 min in 16 male tennis players. Ad libitum fluid intake was recorded throughout the match. Sweat loss from change in nude body mass; sweat electrolyte content from patches applied to the forearm, calf, and thigh, and back of each player; and electrolyte balance derived from sweat, urine, and daily food-intake analysis were measured. Effort intensity was assessed from on-court heart rate compared with data obtained during a maximal treadmill test. Sweat rate (M ± SD) was 1.1 ± 0.4 L/hr, and fluid-ingestion rate was 1.0 ± 0.6 L/hr (replacing 93% ± 47% of fluid lost), resulting in only a small mean loss in body mass of 0.15% ± 0.74%. Large interindividual variabilities in sweat rate (range 0.3–2.0 L/hr) and fluid intake (range 0.31–2.52 L/hr) were noted. Whole-body sweat sodium concentration was 38 ± 12 mmol/L, and total sodium losses during match play were 1.1 ± 0.4 g (range 0.5–1.8 g). Daily sodium intake was 2.8 ± 1.1 g. Indoor match play largely consisted of low-intensity exercise below ventilatory threshold (mean match heart rate was 138 ± 24 beats/min). This study shows that in moderate indoor temperature conditions players ingest sufficient fluid to replace sweat losses. However, the wide range in data obtained highlights the need for individualized fluid-replacement guidance.

Effect of High and Low Rates of Fluid Intake on Post-exercise Rehydration

2002 ◽  
Vol 12 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Eva M.R. Kovacs ◽  
Regina M. Schmahl ◽  
Joan M.G. Senden ◽  
Fred Brouns
Keyword(s):  
Body Weight ◽  
Plasma Volume ◽  
Electrolyte Solution ◽  
Fluid Balance ◽  
Urine Output ◽  
Fluid Intake ◽  
Recovery Period ◽  
Fluid Consumption ◽  
Post Exercise

The effect of a high (H) and a low (L) rate of post-exercise fluid consumption on plasma volume and fluid balance restoration was investigated. Eight well-trained cyclists were dehydrated at 3% of body weight (BW) by cycling at 28 °C. During the recovery period, they ingested a carbohydrate-electrolyte solution in a volume equivalent to 120% of BW loss. Randomly, they ingested 60%, 40%, and 20% in the 1 st, 2nd, and 3rd hours of the recovery period, respectively (H), or 24% · h−1 during 5 hours (L). BW loss was similar for both trials and resulted in a total drink intake of 2.6 ± 0.1 kg. Urine output in H exceeded significantly that of L in the 2nd and 3rd hours. This was reversed in the 5th and 6th hours. Plasma volume and fluid balance increased more rapidly in H compared to L. After 6 hours this difference disappeared. It is concluded that H results in a faster rate of plasma volume and fluid balance restoration compared to L, despite a temporary large urine output.

scholarly journals Fluid Balance, Sweat Na+ Losses, and Carbohydrate Intake of Elite Male Soccer Players in Response to Low and High Training Intensities in Cool and Hot Environments

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 401
Author(s):  
Ian Rollo ◽  
Rebecca K. Randell ◽  
Lindsay Baker ◽  
Javier Yanguas Leyes ◽  
Daniel Medina Leal ◽  
...  
Keyword(s):  
Fluid Balance ◽  
High Intensity ◽  
Fluid Intake ◽  
Sweat Rate ◽  
Carbohydrate Intake ◽  
Soccer Players ◽  
Physiological Strain ◽  
Low Intensity ◽  
Ad Libitum ◽  
Hot Environments

Hypohydration increases physiological strain and reduces physical and technical soccer performance, but there are limited data on how fluid balance responses change between different types of sessions in professional players. This study investigated sweat and fluid/carbohydrate intake responses in elite male professional soccer players training at low and high intensities in cool and hot environments. Fluid/sodium (Na+) losses and ad-libitum carbohydrate/fluid intake of fourteen elite male soccer players were measured on four occasions: cool (wet bulb globe temperature (WBGT): 15 ± 7 °C, 66 ± 6% relative humidity (RH)) low intensity (rating of perceived exertion (RPE) 2–4, m·min−1 40–46) (CL); cool high intensity (RPE 6–8, m·min−1 82–86) (CH); hot (29 ± 1 °C, 52 ± 7% RH) low intensity (HL); hot high intensity (HH). Exercise involved 65 ± 5 min of soccer-specific training. Before and after exercise, players were weighed in minimal clothing. During training, players had ad libitum access to carbohydrate beverages and water. Sweat [Na+] (mmol·L−1), which was measured by absorbent patches positioned on the thigh, was no different between conditions, CL: 35 ± 9, CH: 38 ± 8, HL: 34 ± 70.17, HH: 38 ± 8 (p = 0.475). Exercise intensity and environmental condition significantly influenced sweat rates (L·h−1), CL: 0.55 ± 0.20, CH: 0.98 ± 0.21, HL: 0.81 ± 0.17, HH: 1.43 ± 0.23 (p =0.001), and percentage dehydration (p < 0.001). Fluid intake was significantly associated with sweat rate (p = 0.019), with no players experiencing hypohydration > 2% of pre-exercise body mass. Carbohydrate intake varied between players (range 0–38 g·h−1), with no difference between conditions. These descriptive data gathered on elite professional players highlight the variation in the hydration status, sweat rate, sweat Na+ losses, and carbohydrate intake in response to training in cool and hot environments and at low and high exercise intensities.

High-Intensity Intermittent Exercise and Autonomic Modulation: Effects of Different Volume Sessions

2017 ◽  
Vol 38 (06) ◽  
pp. 468-472 ◽  
Author(s):  
Carlos Iván Mesa Castrillón ◽  
Rodolfo Augusto Travagin Miranda ◽  
Carolina Cabral-Santos ◽  
Lais Manata Vanzella ◽  
Bruno Rodrigues ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
High Intensity ◽  
Intermittent Exercise ◽  
Recovery Period ◽  
Autonomic Modulation ◽  
Physically Active ◽  
Maximal Aerobic Speed ◽  
Lower Volume ◽  
Before And After

AbstractThe aim of this study was to compare heart rate variability (HRV) recovery after 2 sessions of high-intensity intermittent exercise at different volumes (1.25 km [HIIE1.25] and 2.5 km [HIIE2.5]). 13 participants determined their maximal aerobic speed (MAS) and completed 2 HIIE (1:1 at 100% MAS) trials. The heart rate was recorded before and after each session. HRV indicators were calculated according to time (RMSSD and SDNN) and frequency (LF, HF and LF/HF ratio) domains. SDNN and RMSSD presented effect of test (F=20.97; p<0.01 and F=21.00; p<0.01, respectively) and moment (F=6.76; p<0.01 and F=12.30; p<0.01, respectively), without interaction. Even though we did not find an interaction effect for any HRV variables, the HIIE2.5 presented a delay of only 5 min in HRV recovery, when compared to HIIE1.25. However, the effects of the test (SDNN, RMSSD, LF-log, and HF-log) indicate higher autonomic stress during the entire recovery period. These findings may indicate that exercise volume interferes with HRV recovery. If so, physically active subjects may choose a lower volume exercise (i. e., HIIE1.25) in order to promote similar physical fitness adaptations with lower loading on autonomic modulation.

Prolonged whole-body cold water immersion: fluid and ion shifts

1989 ◽  
Vol 66 (1) ◽  
pp. 34-41 ◽  
Author(s):  
P. A. Deuster ◽  
D. J. Smith ◽  
B. L. Smoak ◽  
L. C. Montgomery ◽  
A. Singh ◽  
...  
Keyword(s):  
Plasma Volume ◽  
Thermal Protection ◽  
Cold Water ◽  
Intermittent Exercise ◽  
Water Immersion ◽  
Cold Water Immersion ◽  
Urine Flow ◽  
Whole Body ◽  
Before And After ◽  
Ion Shifts

To characterize fluid and ion shifts during prolonged whole-body immersion, 16 divers wearing dry suits completed four whole-body immersions in 5 degrees C water during each of two 5-day air saturation dives at 6.1 msw. One immersion was conducted at 1000 (AM) and one at 2200 (PM) so that diurnal variations could be evaluated. Fifty-four hours separated the immersions, which lasted up to 6 h; 9 days separated each air saturation dive. Blood was collected before and after immersion; urine was collected for 12 h before, during, and after immersion for a total of 24 h. Plasma volume decreased significantly and to the same extent (approximately 17%) during both AM and PM immersions. Urine flow increased by 236.1 +/- 38.7 and 296.3 +/- 52.0%, urinary excretion of Na increased by 290.4 +/- 89.0 and 329.5 +/- 77.0%, K by 245.0 +/- 73.4 and 215.5 +/- 44.6%, Ca by 211.0 +/- 31.4 and 241.1 +/- 50.4%, Mg by 201.4 +/- 45.9 and 165.3 +/- 287%, and Zn by 427.8 +/- 93.7 and 301.9 +/- 75.4% during AM and PM immersions, respectively, compared with preimmersion. Urine flow and K excretion were significantly higher during the AM than PM. In summary, when subjects are immersed in cold water for prolonged periods, combined with a slow rate of body cooling afforded by thermal protection and enforced intermittent exercise, there is diuresis, decreased plasma volume, and increased excretions of Na, K, Ca, Mg, and Zn.

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