scholarly journals The Utility of Thirst as a Measure of Hydration Status Following Exercise-Induced Dehydration

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2689 ◽  
Author(s):  
William M. Adams ◽  
Lesley W. Vandermark ◽  
Luke N. Belval ◽  
Douglas J. Casa
Keyword(s):  
Body Mass ◽  
Prolonged Exercise ◽  
Recovery Period ◽  
Fluid Replacement ◽  
Hydration Status ◽  
Post Exercise ◽  
Visual Analog Scales ◽  
Hot Environment ◽  
Ad Libitum ◽  
Exercise Induced

The purpose of this study was to examine the perception of thirst as a marker of hydration status following prolonged exercise in the heat. Twelve men (mean ± SD; age, 23 ± 4 y; body mass, 81.4 ± 9.9 kg; height, 182 ± 9 cm; body fat, 14.3% ± 4.7%) completed two 180 min bouts of exercise on a motorized treadmill in a hot environment (35.2 ± 0.6 °C; RH, 30.0 ± 5.4%), followed by a 60 min recovery period. Participants completed a euhydrated (EUH) and hypohydrated (HYPO) trial. During recovery, participants were randomly assigned to either fluid replacement (EUHFL and HYPOFL; 10 min ad libitum consumption) or no fluid replacement (EUHNF and HYPONF). Thirst was measured using both a nine-point scale and separate visual analog scales. The percent of body mass loss (%BML) was significantly greater immediately post exercise in HYPO (HYPOFL, 3.0% ± 1.2%; HYPONF, 2.6% ± 0.6%) compared to EUH (EUHFL, 0.2% ± 0.7%; EUHNF, 0.6% ± 0.5%) trials (p < 0.001). Following recovery, there were no differences in %BML between HYPOFL and HYPONF (p > 0.05) or between EUHFL and EUHNF (p > 0.05). Beginning at minute 5 during the recovery period, thirst perception was significantly greater in HYPONF than EUHFL, EUHNF, and HYPOFL (p < 0.05). A 10 min, ad libitum consumption of fluid post exercise when hypohydrated (%BML > 2%), negated differences in perception of thirst between euhydrated and hypohydrated trials. These results represent a limitation in the utility of thirst in guiding hydration practices.

scholarly journals Movement Technique and Standing Balance After Graded Exercise-Induced Dehydration

2021 ◽  
Vol 56 (2) ◽  
pp. 203-210
Author(s):  
William M. Adams ◽  
Samantha E. Scarneo-Miller ◽  
Lesley W. Vandermark ◽  
Luke N. Belval ◽  
Lindsay J. DiStefano ◽  
...  
Keyword(s):  
Postural Control ◽  
Repeated Measures ◽  
Scoring System ◽  
Neuromuscular Control ◽  
Fluid Replacement ◽  
Hydration Status ◽  
Hot Environment ◽  
Graded Exercise ◽  
Exercise Induced ◽  
Hot Environments

Context Hypohydration has been shown to alter neuromuscular function. However, the longevity of these impairments remains unclear. Objective To examine the effects of graded exercise-induced dehydration on neuromuscular control 24 hours after exercise-induced hypohydration. Design Crossover study. Setting Laboratory. Patients or Other Participants A total of 23 men (age = 21 ± 2 years, height = 179.8 ± 6.4 cm, mass = 75.24 ± 7.93 kg, maximal oxygen uptake [VO2max] = 51.7 ± 5.5 mL·kg−1·min−1, body fat = 14.2% ± 4.6%). Intervention(s) Participants completed 3 randomized exercise trials: euhydrated arrival plus fluid replacement (EUR), euhydrated arrival plus no fluid (EUD), and hypohydrated arrival plus no fluid (HYD) in hot conditions (ambient temperature = 35.2°C ± 0.6°C, relative humidity = 31.3% ± 2.5%). Each trial consisted of 180 minutes of exercise (six 30-minute cycles: 8 minutes at 40% VO2max; 8 minutes, 60% VO2max; 8 minutes, 40% VO2max; 6 minutes, passive rest) followed by 60 minutes of passive recovery. Main Outcome Measure(s) We used the Landing Error Scoring System and Balance Error Scoring System (BESS) to measure movement technique and postural control at pre-exercise, postexercise and passive rest (POSTEX), and 24 hours postexercise (POST24). Differences were assessed using separate mixed-design (trial × time) repeated-measures analyses of variance. Results The magnitude of hypohydration at POSTEX was different among EUR, EUD, and HYD trials (0.2% ± 1%, 3.5% ± 1%, and 5% ± 0.9%, respectively; P &lt; .05). We observed no differences in Landing Error Scoring System scores at pre-exercise (2.9 ± 1.6, 3.0 ± 2.1, 3.0 ± 2.0), POSTEX (3.3 ± 1.5, 3.0 ± 2.0, 3.1 ± 1.9), or POST24 (3.3 ± 1.9, 3.2 ± 1.4, 3.3 ± 1.6) among the EUD, EUR, and HYD trials, respectively (P = .90). Hydration status did not affect BESS scores (P = .11), but BESS scores at POSTEX (10.4 ± 1.1) were greater than at POST24 (7.7 ± 0.9; P = .03). Conclusions Whereas exercise-induced dehydration up to 5% body mass did not impair movement technique or postural control 24 hours after a prolonged bout of exercise in a hot environment, postural control was impaired at 60 minutes after prolonged exercise in the heat. Consideration of the length of recovery time between bouts of exercise in hot environments is warranted.

scholarly journals Influence of Fluid Replacement on Short-Term Recovery and Subsequent Exercise Performance

1998 ◽  
Vol 4 (2) ◽  
pp. 37-49
Author(s):  
Stephen H. S. WONG
Keyword(s):  
Prolonged Exercise ◽  
Recovery Period ◽  
Electrolyte Solutions ◽  
Volume Of Fluid ◽  
Fluid Replacement ◽  
Hydration Status ◽  
Endurance Capacity ◽  
Drinking Patterns ◽  
Short Term ◽  
Vigorous Exercise

LANGUAGE NOTE | Document text in English; abstract also in Chinese.Rapid fluid replacement and replenishment of muscle glycogen after prolonged exercise are vital for optimal substrate provision, cardiovascular function, and thermoregulation during subsequent bouts of vigorous exercise on the same day. This paper reviews recent work relating to the effects of rehydration with carbohydrate-electrolyte solutions during a short-term recovery period on hydration status, physiological responses, and subsequent endurance capacity. Issues investigated and discussed were drinking patterns, amount of carbohydrate (CHO) consumed, and the volume of fluid ingested. The data are presented as a series of summaries of experiments, followed by a discussion of the implications. The main findings of the studies reported suggest that in order to achieve euhydration during short-term recovery, a volume of fluid substantially larger than that lost must be ingested. The provision of additional CHO would be expected to restore the body's CHO stores to a greater extent than a smaller amount of CHO during the recovery and, thereby, improve the subsequent endurance capacity. However, this was not the case. It appears that the ingestion of large amounts of CHO, during a short recovery period, resulted in disturbances in fat and CHO metabolism which prevented an improvement in endurance capacity during subsequent exercise, after consumption of the additional CHO.運動後迅速補充水份及恢復肌肉內的糖元對同日要進行的激烈運動十分重要，因爲能量代謝、心肺功能及體溫調節也以此爲基礎。本文主要綜述最近有關此課題之研究，旨在探討在含有碳水化合物及電解質之飮品影響下，體內水份所作出之調節、各項生理變化及恢復後之運動能力。研究結果顯示，若要在短時間之恢復期內重新達至水份平衡，人體有需要攝取比在運動時所失去之水份爲多之液體。在此短暫恢復期間，若攝取大量的碳水化合物將會引致能量代謝出現不正常的反應，並會影響隨後的運動能力。

scholarly journals PL - 029 Responses of Urine and Blood Biochemical Markers to Exercise-induced Body Fluid Losses in Elite Chinese Road Cyclists

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Qi Han ◽  
Jinde Fu ◽  
Jing Shao ◽  
Qirong Wang ◽  
Zilong Fang ◽  
...  
Keyword(s):  
Exercise Performance ◽  
Muscle Injury ◽  
Performance Test ◽  
Fluid Intake ◽  
Fluid Replacement ◽  
Hydration Status ◽  
Performance Tests ◽  
Sweat Loss ◽  
Post Exercise ◽  
Exercise Induced

Objective To examine biochemistry parameters regarding exercise induced fatigue, e.g. Sweat Loss (SL), Creatine Kinase (CK), Lactate Dehydrogenase (LDH), Blood Urinary Nitrogen (BUN), etc. Methods This study examined Sweat Loss and blood biochemistry biomarkers regarding fatigue and muscle injury among elite cyclists under a training mode of 120 min moderate workload at 50 - 70% VO2max, then, 10 min relaxation, and then, followed up with a 20 min of spinning session over 85% VO2max. 12 healthy elite Chinese male cyclists (22.6 ± 2.9 years old, 78.3 ± 5.7 kg in weight, 184.6 ± 4.3 cm in height) were recruited. They performed four exercise performance tests throughout this study with 15 days washout period in between. Blood serum tests and urine tests were taken both pre- and post-exercise tests, and dynamic cardio-respiratory hardware (MetaMax 3B, Cortex Biophysik, Germany) was applied during each of their test. There were 2 different sport beverages available. The fluid replacement plan was a double blind crossover design. The volume of fluid intake was in accordance with ACSM recommendation for fluid replacement. Those who were assigned with sport beverage A (6% carbohydrate with 1% peptide) for the first and second performance tests, will be re-assigned to sport beverage B (6% carbohydrate without peptide) for the third and fourth performance tests, vice versa. Notes were taken for the volume of fluid intake to calculate the estimated Sweat Loss. Results We found 91.7% trials have increased LDH, 88.9% trials have increased CK, and 100% trials have been observed increased BUN right after exercise performance test. Even with sufficient water supply, athletes hydration status were getting worse after exercise performance test, their urine USG results were 1.024 ± 0.006 and 1.027 ± 0.006 for pre- and post-exercise performance test respectively. Their dehydration status quantified by the percentage change in body mass (%BM) was 1.86% ± 1.03% with a 95% confidence interval ranging from 1.57% to 2.15%. Conclusions Though, with sufficient water supply, athletes hydration status were getting worse after exercise performance test considering Sweat Loss and blood biochemistry indicators regarding fatigue and muscle injury.

The Influence of Heat Acclimation and Hypohydration on Post-Weight-Loss Exercise Performance

2020 ◽  
Vol 15 (2) ◽  
pp. 213-221
Author(s):  
Oliver R. Barley ◽  
Dale W. Chapman ◽  
Georgios Mavropalias ◽  
Chris R. Abbiss
Keyword(s):  
Body Mass ◽  
Exercise Performance ◽  
Fluid Intake ◽  
Heat Acclimation ◽  
Hydration Status ◽  
Performance Variables ◽  
Pooled Data ◽  
Ad Libitum ◽  
Experimental Trials ◽  
Food And Fluid Intake

Purpose: To examine the influence of fluid intake on heat acclimation and the subsequent effects on exercise performance following acute hypohydration. Methods: Participants were randomly assigned to 1 of 2 groups, either able to consume water ad libitum (n = 10; age 23 [3] y, height 1.81 [0.09] m, body mass 87 [13] kg; HAW) or not allowed fluid (n = 10; age 26 [5] y, height 1.76 [0.05] m, body mass 79 [10] kg; HANW) throughout 12 × 1.5-h passive heat-acclimation sessions. Experimental trials were completed on 2 occasions before (2 baseline trials) and 1 following the heat-acclimation sessions. These sessions involved 3 h of passive heating (45°C, 38% relative humidity) to induce hypohydration followed by 3 h of ad libitum food and fluid intake after which participants performed a repeat sled-push test to assess physical performance. Urine and blood samples were collected before, immediately, and 3 h following hypohydration to assess hydration status. Mood was also assessed at the same time points. Results: No meaningful differences in physiological or performance variables were observed between HANW and HAW at any time point. Using pooled data, mean sprint speed was significantly (P < .001) faster following heat acclimation (4.6 [0.7] s compared with 5.1 [0.8] s). Furthermore, heat acclimation appeared to improve mood following hypohydration. Conclusions: Results suggest that passive heat-acclimation protocols may be effective at improving short-duration repeat-effort performance following acute hypohydration.

scholarly journals Ad Libitum Fluid Consumption via Self- or External Administration

2015 ◽  
Vol 50 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Susan W. Yeargin ◽  
Megan E. Finn ◽  
Lindsey E. Eberman ◽  
Matthew J. Gage ◽  
Brendon P. McDermott ◽  
...  
Keyword(s):  
Body Mass ◽  
Repeated Measures ◽  
Athletic Trainers ◽  
Urine Osmolality ◽  
Time Frame ◽  
Hydration Status ◽  
Fluid Consumption ◽  
Self Administration ◽  
Average Volume ◽  
Ad Libitum

Context: During team athletic events, athletic trainers commonly provide fluids with water bottles. When a limited number of water bottles exist, various techniques are used to deliver fluids. Objective: To determine whether fluid delivered via water-bottle administration influenced fluid consumption and hydration status. Design: Crossover study. Setting: Outdoor field (22.2°C ± 3.5°C). Patients or Other Participants: Nineteen participants (14 men, 5 women, age = 30 ± 10 years, height = 176 ± 8 cm, mass = 72.5 ± 10 kg) were recruited from the university and local running clubs. Intervention(s): The independent variable was fluid delivery with 3 levels: self-administration with mouth-to-bottle direct contact (SA-DC), self-administration with no contact between mouth and bottle (SA-NC), and external administration with no contact between the mouth and the bottle (EA-NC). Participants warmed up for 10 minutes before completing 5 exercise stations, after which an ad libitum fluid break was given, for a total of 6 breaks. Main Outcome Measure(s): We measured the fluid variables of total volume consumed, total number of squirts, and average volume per squirt. Hydration status via urine osmolality and body-mass loss, and perceptual variables for thirst and fullness were recorded. We calculated repeated-measures analyses of variance to assess hydration status, fluid variables, and perceptual measures to analyze conditions across time. Results: The total volume consumed for EA-NC was lower than for SA-DC (P = .001) and SA-NC (P = .001). The total number of squirts for SA-DC was lower than for SA-NC (P = .009). The average volume per squirt for EA-NC was lower than for SA-DC (P = .020) and SA-NC (P = .009). Participants arrived (601.0 ± 21.3 mOsm/L) and remained (622.3 ± 38.3 mOsm/L) hydrated, with no difference between conditions (P = .544); however, the EA-NC condition lost more body mass than did the SA-DC condition (P = .001). There was no main effect for condition on thirst (P = .147) or fullness (P = .475). Conclusions: External administration of fluid decreased total volume consumed via a decreased average volume per squirt. The SA-DC method requires fewer squirts within a specific time frame. Fluid breaks every 15 minutes resulted in maintenance of euhydration; however, loss of body mass was influenced by fluid administration. Athletic trainers should avoid external administration to promote positive hydration behaviors. When fluid is self-administered, individual bottles may be the best clinical practice because more volume can be consumed per squirt.

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 Accuracy of Urine Color to Detect Equal to or Greater Than 2% Body Mass Loss in Men

2015 ◽  
Vol 50 (12) ◽  
pp. 1306-1309 ◽  
Author(s):  
Amy L. McKenzie ◽  
Colleen X. Muñoz ◽  
Lawrence E. Armstrong
Keyword(s):  
Mass Loss ◽  
Likelihood Ratio ◽  
Body Mass ◽  
Positive Likelihood Ratio ◽  
Negative Likelihood Ratio ◽  
Hydration Status ◽  
Body Mass Loss ◽  
Diagnostic Efficacy ◽  
Hot Environment ◽  
Urine Color

Context  Clinicians and athletes can benefit from field-expedient measurement tools, such as urine color, to assess hydration state; however, the diagnostic efficacy of this tool has not been established. Objective  To determine the diagnostic accuracy of urine color assessment to distinguish a hypohydrated state (≥2% body mass loss [BML]) from a euhydrated state (&lt;2% BML) after exercise in a hot environment. Design  Controlled laboratory study. Setting  Environmental chamber in a laboratory. Patients or Other Participants  Twenty-two healthy men (age = 22 ± 3 years, height = 180.4 ± 8.7 cm, mass = 77.9 ± 12.8 kg, body fat = 10.6% ± 4.6%). Intervention(s)  Participants cycled at 68% ± 6% of their maximal heart rates in a hot environment (36°C ± 1°C) for 5 hours or until 5% BML was achieved. At the point of each 1% BML, we assessed urine color. Main Outcome Measure(s)  Diagnostic efficacy of urine color was assessed using receiver operating characteristic curve analysis, sensitivity, specificity, and likelihood ratios. Results  Urine color was useful as a diagnostic tool to identify hypohydration after exercise in the heat (area under the curve = 0.951, standard error = 0.022; P &lt; .001). A urine color of 5 or greater identified BML ≥2% with 88.9% sensitivity and 84.8% specificity (positive likelihood ratio = 5.87, negative likelihood ratio = 0.13). Conclusions  Under the conditions of acute dehydration due to exercise in a hot environment, urine color assessment can be a valid, practical, inexpensive tool for assessing hydration status. Researchers should examine the utility of urine color to identify a hypohydrated state under different BML conditions.

Drinking Behavior and Exercise-Thermal Stress: Role of Drink Carbonation

1994 ◽  
Vol 4 (1) ◽  
pp. 8-21 ◽  
Author(s):  
Matthew S. Hickey ◽  
David L. Costill ◽  
Scott W. Trappe
Keyword(s):  
Thermal Stress ◽  
Body Fluid ◽  
Prolonged Exercise ◽  
Physiological Responses ◽  
Drinking Behavior ◽  
Recovery Period ◽  
Fluid Consumption ◽  
Blood Samples ◽  
Ad Libitum

This study investigated the influence of drink carbonation and carbohydrate content on ad libitum drinking behavior and body fluid and electrolyte responses during prolonged exercise in the heat. Eight competitive male runners completed three 2-hr treadmill runs at 60%in an environmental chamber maintained atand 40% RH. Three test drinks were used: 8% carbohydrate, low carbonation (8%-C); 8% carbohydrate, noncarbonated (8%-NC), and water (0%-NC). Blood samples were taken preexercise (0), at 60 and 120 min of exercise, and at 60 min of recovery (+60 min). The data suggest that while reports of heartburn tend to be higher on 8% carbohydrate drinks than on 0%-NC, this does not appear to be a function of drink carbonation. Similarly, the increased frequency of heartbum did not significantly reduce fluid consumption either during exercise or during a 60-min recovery period. Importantly, no differences were observed between fluid and electrolyte, or thermoregulatory responses to the three sport drinks. Thus, consumption of low-carbonation beverages does not appear to significantly influence drinking behavior or the related physiological responses during prolonged exercise in the heat.

A Comparison of Three Fluid Replacement Strategies for Maintaining Euhydration During Prolonged Exercise

1997 ◽  
Vol 22 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Jan M. Schroeder ◽  
Kris L. Heck ◽  
Jeffrey A. Potteiger
Keyword(s):  
Heart Rate ◽  
Plasma Volume ◽  
Prolonged Exercise ◽  
Fluid Intake ◽  
Fluid Replacement ◽  
Water Delivery ◽  
Total Water ◽  
Significant Difference ◽  
Ad Libitum ◽  
Total Water Intake

The effectiveness of a new water delivery system (the Water-Del) was examined for maintaining euhydration compared to other fluid replacement strategies. Subjects (N = 10) performed three 60-min cycling trials (@ 50% of VO2max) in an environmental chamber (27 °C; RH = 50%). Trials were randomly assigned from Water-Del (metered: 200 ml water every 15 min), ad libitum every 15 min (ad-lib-15), and ad libitum (ad-lib). Total water intake (TWI), changes in plasma volume (ΔPV), body Weight (ΔBW), thirst, skin temperature (Tsk), and heart rate (HR) were measured. A significant difference (p ≤.05) among trials was observed for TWI, with metered (1.200 ± 0.12 ml) being greater than ad-lib-15 (358 ± 48 ml) and ad-lib (522 ± 106 ml). No significant difference was found for ΔPV. A significant difference (p ≤.05) for ΔHW was observed with metered (0.28 ± 0.16 kg) being different than ad-lib-l5 (−0.63 ± 0.12 kg) and ad-lib (−0.34 ± 0.14 kg). No significant differences (p > .05) were found for thirst, Tsk, or HR. The Water-Del provides for greater fluid intake during exercise compared to other replacement strategies. Key words: hydration, dehydration, plasma volume

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