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Benjamin CL, Dobbins LW, Sullivan SG, Rogers RR, Williams TD, Marshall MR, Ballmann CG. The Effect of Fluid Availability on Consumption and Perceptual Measures during Aerobic Exercise. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:1310. [PMID: 36674064 PMCID: PMC9858706 DOI: 10.3390/ijerph20021310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 06/17/2023]
Abstract
Fluid availability may alter drinking behavior; however, it is currently unknown if the availability of fluid impacts behavior and gastrointestinal issues (GI) that are often associated with increased fluid intake. The purpose of this study was to determine if ad libitum (AL) versus periodic (PER) fluid intake influences fluid consumption and GI distress during exercise in trained athletes. Male and female Division I NCAA Cross Country athletes (n = 11; age = 20 ± 1 years) participated in this counterbalanced crossover study. Each participant completed a moderate intensity 10 km run on two separate occasions. In one trial, participants had unlimited availability to fluid to consume AL. In the other trial, participants consumed PER fluid at stations placed every 3.2 km. Assurance of euhydration prior to each trial was confirmed via urine specific gravity (USG) and urine color. Subjective perceptions of thirst and gastric fullness were assessed pre- and post-exercise via Likert questioning and a visual analog scale, respectively. Participants started each trial euhydrated (AL = 1.009 USG ± 0.009; PER = 1.009 USG ± 0.009; urine color AL, 3 ± 1; urine color PER, 2 ± 1). Fluid volume consumption was significantly higher during the AL condition compared to PER (p = 0.050). Thirst significantly increased from pre- to post-run regardless of treatment (p < 0.001); however, there was no significant difference between the groups (p = 0.492). Feelings of fullness did not change pre-post trial (p = 0.304) or between trials (p = 0.958). Increased fluid availability allows for increased fluid consumption without the negative experience of GI discomfort.
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Affiliation(s)
| | - Luke W. Dobbins
- Department of Kinesiology, Samford University, Birmingham, AL 35226, USA
| | | | - Rebecca R. Rogers
- Department of Kinesiology, Samford University, Birmingham, AL 35226, USA
- SHP Research Collaborative, University of Alabama at Birmingham, Birmingham, AL 35226, USA
| | - Tyler D. Williams
- Department of Kinesiology, Samford University, Birmingham, AL 35226, USA
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Capitán-Jiménez C, Aragón-Vargas LF. Post-Exercise Voluntary Drinking Cessation Is Associated with the Normalization of Plasma Osmolality and Thirst Perception, but Not of Urine Indicators or Net Fluid Balance. Nutrients 2022; 14:nu14194188. [PMID: 36235840 PMCID: PMC9572470 DOI: 10.3390/nu14194188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/20/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
Post-exercise rehydration has been widely studied, with particular emphasis on retention of ingested fluid; comparatively little research has been conducted on why we drink more or less. To identify physiological values corresponding to voluntary drinking cessation (VDC), nine males exercised intermittently at 70−80% HRmax in the heat (WBGT = 28.1 ± 0.7 °C) to achieve a dehydration of approximately 4.0% body mass (BM). After exercise, participants were instructed to drink water as long and as much as they needed. Urine color (Ucolor), specific gravity (USG), osmolality (Uosm), plasma osmolality (Posm), fullness, BM, and thirst perception (TP) were measured pre- and post-exercise and at VDC. Each variable was compared for the three points in time with a one-way ANOVA. Participants reached dehydration of −3.6 ± 0.3% BM. Pre-exercise USG (1.022 ± 0.004) was lower than at VDC (1.029 ± 0.004, p = 0.022), Uosm did not change over time (p = 0.217), and Ucolor was lower pre-exercise (3.4 ± 0.7) vs. post-exercise (5.5 ± 1.23, p = 0.0008) and vs. VDC (6.3 ± 1.1, p < 0.0001). Posm showed a difference between pre-exercise (289.5 ± 2.3) and post-exercise (297.8 ± 3.9, p = 0.0006) and between post-exercise and VDC (287.3 ± 5.4, p < 0.0001). TP post-exercise (96.4 ± 4.34) was significantly higher than pre-exercise (36.2 ± 19.1) and VDC (25.0 ± 18.2, p < 0.0001). At VDC, participants had recovered 58.7 ± 12.1% of BM loss. At the point of voluntary drinking cessation, Posm and thirst perception had returned to their pre-exercise values, while rehydration relative to initial BM was still incomplete.
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Affiliation(s)
- Catalina Capitán-Jiménez
- Department of Nutrition, Universidad Hispanoamericana, San Jose 10101, Costa Rica
- Human Movement Science Research Center, Universidad de Costa Rica, San Pedro 11501, Costa Rica
- Correspondence: ; Tel.: +506-88749572
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Hydration Strategies for Physical Activity and Endurance Events at High (>2500 m) Altitude: A Practical Management Article. Clin J Sport Med 2022; 32:407-413. [PMID: 33852437 DOI: 10.1097/jsm.0000000000000919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/11/2021] [Indexed: 02/02/2023]
Abstract
A growing number of adventurous athletes are seeking new challenges through endurance events or physical activities held at high altitude (>2500 m). This coincides with a significant increase in the numbers of trekkers who ascend into the world's mountains. Altitude itself influences and complicates the athlete's effective and safe hydration. This article considers the physiology of adaptation to altitude and the effects on hydration at altitude compared with sea level, reviews the "ad libitum versus programmed hydration" controversy in conventional endurance event hydration, examines the evidence for extrapolation of sea level hydration strategies to the high-altitude environment, and synthesizes these disparate factors into a set of practical recommendations for hydration management during high-altitude physical activity. The guidelines will be relevant to participants of physical activity at altitude and health care staff who may care for them in the preparation or performance phases of their adventure.
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Prevalence of Dehydration and the Relationship with Fluid Intake and Self‐Assessment of Hydration Status in Czech First League Soccer Players. J Hum Kinet 2022; 82:101-110. [PMID: 36157002 PMCID: PMC9465733 DOI: 10.2478/hukin-2022-0035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
The objective of this cross-sectional study was to evaluate the hydration status of Czech First League soccer players, and to compare the reported fluid intake, perceived fluid intake and thirst sensation of euhydrated (EU) and dehydrated (DE) players. The study involved 124 Czech male professional soccer players (age 25.2±5.0 years) participating in annual winter, pre-season laboratory testing. Hydration status was assessed based on urine specific gravity (USG), euhydration was set at USG≤1.020. Fluid intake and thirst perception were evaluated by a questionnaire. The sample mean for USG was 1.021±0.008, 56% of players were dehydrated. Reported daily fluid intake was significantly (p<0.001, d=0.95, large effect) higher in EU compared to DE players. Daily fluid intake negatively correlated with USG (rS=-0.46, p<0.001, medium effect). The fluid intake perception score was significantly (p=0.005, d=0.54, medium effect) better in EU compared to DE players. Reported intake perception scores negatively correlated with USG (rS=-0.32, p<0.001, medium effect). However, there was no correlation (rS=-0.09, p=0.34, trivial effect) between thirst perception scores and USG. Thirst perception scores were not significantly different between EU and DE players (p=0.35, d=0.18, trivial effect). Our results indicated that self-assessment of both daily fluid intake and perceived fluid intake matched with objective hydration status, while self-assessment of thirst perception was not an appropriate indicator of hydration status in elite soccer players.
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Capitán-Jiménez C, Aragón-Vargas LF. Awareness of Fluid Losses Does Not Impact Thirst during Exercise in the Heat: A Double-Blind, Cross-Over Study. Nutrients 2021; 13:nu13124357. [PMID: 34959909 PMCID: PMC8705747 DOI: 10.3390/nu13124357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/31/2021] [Accepted: 08/17/2021] [Indexed: 11/22/2022] Open
Abstract
Background: Thirst has been used as an indicator of dehydration; however, as a perception, we hypothesized that it could be affected by received information related to fluid losses. The purpose of this study was to identify whether awareness of water loss can impact thirst perception during exercise in the heat. Methods: Eleven males participated in two sessions in random order, receiving true or false information about their fluid losses every 30 min. Thirst perception (TP), actual dehydration, stomach fullness, and heat perception were measured every 30 min during intermittent exercise until dehydrated by ~4% body mass (BM). Post exercise, they ingested water ad libitum for 30 min. Results: Pre-exercise BM, TP, and hydration status were not different between sessions (p > 0.05). As dehydration progressed during exercise, TP increased significantly (p = 0.001), but it was the same for both sessions (p = 0.447). Post-exercise water ingestion was almost identical (p = 0.949) in the two sessions. Conclusion: In this study, thirst was a good indicator of fluid needs during exercise in the heat when no fluid was ingested, regardless of receiving true or false water loss information.
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Affiliation(s)
- Catalina Capitán-Jiménez
- Human Movement Science Research Center, University of Costa Rica, Montes de Oca, San José 11-501-2060, Costa Rica;
- Department of Nutrition, Hispanoamerican University, El Carmen, San José 10101, Costa Rica
- Correspondence:
| | - Luis F. Aragón-Vargas
- Human Movement Science Research Center, University of Costa Rica, Montes de Oca, San José 11-501-2060, Costa Rica;
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Claveau P, Deshayes TA, Jeker D, Pancrate T, Goulet EDB. Provision of instructions to drink ad libitum or according to thirst sensation: impact during 120 km of cycling in the heat in men. Appl Physiol Nutr Metab 2021; 47:1-8. [PMID: 34461024 DOI: 10.1139/apnm-2021-0476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The terms drinking to thirst and ad libitum drinking are used interchangeably, but should they? We investigated the differences in how athletes consumed fluids during exercise when instructed to drink according to thirst or ad libitum. Using a randomized, crossover, and counterbalanced design, 10 males (27 ± 4 y) cycled 120 km (48 ± 4% of peak power, 33 °C, 40% relative humidity) on 2 occasions, while drinking water according to thirst or ad libitum. Participants covered the cycling trials in 222 ± 11 min (p = 0.29). Although the body mass loss at the end of exercise and total volume of water consumed were similar between trials, thirst perception before each sip and the volume consumed per sip were significantly higher with thirst than ad libitum drinking, whereas the total number of sips was significantly lower with thirst than ad libitum drinking. Perceived exertion, rectal temperature, and heart rate were all significantly higher with thirst than ad libitum drinking, but the difference was trivial. In conclusion, thirst and ad libitum drinking are associated with different drinking patterns, but equally maintain fluid balance during prolonged exercise. The terms drinking to thirst and ad libitum drinking can be used interchangeably to guide fluid intake during prolonged exercise. Novelty: Both strategies are associated with different patterns of fluid ingestion during prolonged exercise, but are equally effective in maintaining fluid balance. Perceived exertion, rectal temperature, and heart rate are regulated dissimilarly by thirst and ad libitum drinking, but the difference is trivial.
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Affiliation(s)
- Pascale Claveau
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Thomas A Deshayes
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
- Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC, Canada
| | - David Jeker
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Timothée Pancrate
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Eric D B Goulet
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
- Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC, Canada
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Armstrong LE. Rehydration during Endurance Exercise: Challenges, Research, Options, Methods. Nutrients 2021; 13:887. [PMID: 33803421 PMCID: PMC8001428 DOI: 10.3390/nu13030887] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/27/2021] [Accepted: 03/01/2021] [Indexed: 01/18/2023] Open
Abstract
During endurance exercise, two problems arise from disturbed fluid-electrolyte balance: dehydration and overhydration. The former involves water and sodium losses in sweat and urine that are incompletely replaced, whereas the latter involves excessive consumption and retention of dilute fluids. When experienced at low levels, both dehydration and overhydration have minor or no performance effects and symptoms of illness, but when experienced at moderate-to-severe levels they degrade exercise performance and/or may lead to hydration-related illnesses including hyponatremia (low serum sodium concentration). Therefore, the present review article presents (a) relevant research observations and consensus statements of professional organizations, (b) 5 rehydration methods in which pre-race planning ranges from no advanced action to determination of sweat rate during a field simulation, and (c) 9 rehydration recommendations that are relevant to endurance activities. With this information, each athlete can select the rehydration method that best allows her/him to achieve a hydration middle ground between dehydration and overhydration, to optimize physical performance, and reduce the risk of illness.
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Affiliation(s)
- Lawrence E Armstrong
- Human Performance Laboratory and Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA
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Atkins WC, McDermott BP, Kanemura K, Adams JD, Kavouras SA. Effects of Hydration Educational Intervention in High School Football Players. J Strength Cond Res 2021; 35:385-390. [PMID: 33337701 DOI: 10.1519/jsc.0000000000003866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Whitley C Atkins
- Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas
| | - Brendon P McDermott
- Exercise Science Research Center, University of Arkansas, Fayetteville, Arkansas
| | | | - J D Adams
- Department of Health and Human Performance, College of Charleston, Charleston, South Carolina; and
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Wardenaar FC, Thompsett D, Vento KA, Bacalzo D. A lavatory urine color (LUC) chart method can identify hypohydration in a physically active population. Eur J Nutr 2021; 60:2795-2805. [PMID: 33416980 DOI: 10.1007/s00394-020-02460-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE To provide a new and efficient at-the-toilet-bowl method of self-assessing urine concentration via urine color (Uc) to identify hypohydration. METHODS A large athletic population (n = 189) delivered a urine sample, then chose a color panel that was displayed on the back wall of the lavatory stall. Selection was based on duration of urine voiding time, so that for a short-duration, the lighter panel was selected; for a mid-duration, the mid color panel; and for a longer-void-duration, the darker panel was selected. Then, subjects noted if their urine was lighter than, similar to, or darker than the selected color panel. Trained investigators also rated subjects' urine samples. To assess validity of Uc classification, the outcome was compared with a urine concentration (urine specific gravity, USG, and urine osmolality) threshold indicating hypohydration. RESULTS Urine color was scored similarly by subjects and investigators (P = 0.99). Based on receiver operating curves (ROC), the method scored fair, i.e., the area under the curve ranging 0.73-0.82, with an accuracy of participants and investigators correctly classifying 72% and 75% urine samples compared to a USG threshold of 1.020, respectively, and 62% and 70% compared to a urine osmolality threshold of 836 mmol·kg-1, respectively. CONCLUSION This new lavatory urine color (LUC) method of scoring Uc levels to assess potential hypohydration gives results similar to those of traditional urine color charts, but it has the advantage of an immediate assessment of hydration status based on scoring urine color directly from the toilet bowl.
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Affiliation(s)
- Floris C Wardenaar
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA.
| | - Daniel Thompsett
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA
| | - Kaila A Vento
- College of Health Solutions, Arizona State University, Phoenix, AZ, USA
| | - Dean Bacalzo
- Herberger Institute for Design and the Arts, Arizona State University, Tempe, AZ, USA
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Paternoster N, Baggio E, Pelosi E. Personalized hydratation status in endurance and ultra-endurance: A review. MEDITERRANEAN JOURNAL OF NUTRITION AND METABOLISM 2020. [DOI: 10.3233/mnm-200434] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
This review aims to investigate the physiological mechanisms that underlie the hydro-electrolyte balance of the human body and the most appropriate hydration modalities for individuals involved in physical and sports activities, with a focus on ultra-endurance events. The role of effective hydration in achieving optimal sports performance is also investigated. An adequate pre-hydration is essential to perform physical and sporting activity in a condition of eu-hydration and to mantain physiologic levels of plasma electrolyte. To achieve these goals, athletes need to consume adequate drinks together with consuming meals and fluids, in order to provide an adequate absorption of the ingested fluids and the expulsion of those in excess through diuresis. Therefore, there are important differences between individuals in terms of sweating rates, the amount of electrolytes loss and the specific request of the discipline practiced and the sporting event to pursue.
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Affiliation(s)
- Nicolò Paternoster
- Centro di Medicina, Venice, Italy
- Centro Medico Fisioterapico, Magenta, Padova, Italy
| | | | - Ettore Pelosi
- Poliambulatorio Vitalia, Torino, Italy
- Centro PET Irmet – Affidea, Torino, Italy
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Arriel RA, Meireles A, Hohl R, Marocolo M. Ischemic preconditioning improves performance and accelerates the heart rate recovery. J Sports Med Phys Fitness 2020; 60:1209-1215. [PMID: 32550713 DOI: 10.23736/s0022-4707.20.10822-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Previous studies have assessed the effects of ischemic preconditioning (IPC) on exercise performance and physiological variables, such as lactate and muscle deoxygenation. In this study, we verified the IPC effects on performance and heart rate during and immediately after a maximal incremental cycling test (ICT). METHODS Eighteen recreationally trained cyclists (28±4 years) were allocated to one of three groups: IPC, SHAM and Control. After the first visit to familiarization, cyclists attended the laboratory on two separate occasions to perform an ICT: in the 1<sup>st</sup> visit they performed the reference test (baseline), and in 2<sup>nd</sup> the test ischemic preconditioning (2 cycles of 5-min occlusion [at 50 mm Hg above systolic arterial pressure]/ 5-min reperfusion), SHAM (identical to ischemic preconditioning, but at 20 mm Hg) or control (no occlusion) interventions (post intervention). During the ICT, heart rate, power output and perceived exertion were measured and the heart rate was monitored throughout the recovery. RESULTS Only ischemic preconditioning group improved performance time by 4.9±4.0% and decreased heart rate at submaximal point during ICT, of 170±8 to 166±8 bpm (P<0.05). Also, IPC promoted faster heart rate recovery, mainly on first minute (from 151±9 to 145±8 bpm; P<0.05), compared to baseline. No differences for other parameters were found. CONCLUSIONS Two cycles of five minutes of ischemia were relevant to produce positive effects on performance and alter the heart rate during and soon after ICT.
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Affiliation(s)
- Rhaí A Arriel
- Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Anderson Meireles
- Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Rodrigo Hohl
- Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Moacir Marocolo
- Department of Physiology, Federal University of Juiz de Fora, Juiz de Fora, Brazil -
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Ito H, Kabayma S, Goto K. Effects of electrolyzed hydrogen water ingestion during endurance exercise in a heated environment on body fluid balance and exercise performance. Temperature (Austin) 2020; 7:290-299. [PMID: 33117861 PMCID: PMC7575226 DOI: 10.1080/23328940.2020.1742056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Electrolyzed hydrogen water (EHW) is generated at a cathode. It contains many hydrogen molecules with high alkaline properties. The physiological effects of ingesting EHW during endurance exercise are unclear. The purpose of this study was to determine the effects of ingesting EHW during endurance exercise in a heated environment on body fluid balance and exercise performance. Twelve triathletes (20.0 ± 1.3 years, 171 ± 6 cm, 60.6 ± 3.9 kg, V̇O2max 67.1 ± 3.8 mL/kg/min) performed pedaling exercise for 60 min at 65% of V̇O2max consuming either purified water (CON trial) or EHW (EHW trial) and then conducted an incremental pedaling test. Blood parameters, tissue temperature, and respiratory variables were determined during 60 min of exercise. The time to exhaustion (TTE) during the incremental pedaling test was also determined. Body weights were 1.1 ± 0.4 kg lower after exercise, with no significant differences between trials. Plasma volume and serum osmolality and blood sodium and potassium concentrations significantly changed with exercise, but no significant differences were observed between trials. The pH, blood lactate and bicarbonate concentrations, and changes in skin and muscle temperature did not significantly differ between the two trials. Energy expenditure during exercise was significantly (P = 0.04) lower in the EHW trial (13.2 ± 0.5 kcal/min) than in the CON trial (13.7 ± 0.4 kcal/min). TTE did not significantly differ between the trials. In conclusion, EHW ingestion during endurance exercise in a heated environment decreased energy expenditure but did not affect body fluid balance or exercise performance. Abbreviations: CON: control trial; CV: coefficient of variation; EHW: electrolyzed hydrogen water; HR: heart rate; RPE: rating of perceived exertion; SE: standard error; TP: total protein; TTE: time to exhaustion.
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Affiliation(s)
- Hiroto Ito
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | | | - Kazushige Goto
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
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Effect of ad libitum intake of lactose-free milk on subsequent performance of collegiate badminton athletes. GERMAN JOURNAL OF EXERCISE AND SPORT RESEARCH 2019. [DOI: 10.1007/s12662-019-00592-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Nolte HW, Nolte K, Hew-Butler T. Ad libitum water consumption prevents exercise-associated hyponatremia and protects against dehydration in soldiers performing a 40-km route-march. Mil Med Res 2019; 6:1. [PMID: 30678725 PMCID: PMC6346586 DOI: 10.1186/s40779-019-0192-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/08/2019] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND It remains unclear if ad libitum water drinking, as a hydration strategy, prevents exercise-associated hyponatremia (EAH) during prolonged exercise. The aim of this study was to determine the incidence of EAH within the broader context of fluid regulation among soldiers performing a 40-km route-march ingesting water ad libitum. METHODS Twenty-eight healthy male soldiers participated in this observational trial. Pre- and post-exercise body mass, blood and urine samples were collected. Blood samples were assessed for serum sodium ([Na+]), glucose, creatinine, urea nitrogen (BUN), plasma osmolality, creatine kinase (CK), and plasma arginine vasopressin (AVP) concentrations. Plasma volume (PV) was calculated using hematocrit and hemoglobin. Urine samples were analyzed for osmolality and [Na+]. Water intake was assessed by weighing bottles before, during and after the march. The mean relative humidity was 55.7% (21.9-94.3%) and the mean dry bulb temperature was 27.1 °C (19.5 °C - 37.0 °C) during the exercise. RESULTS Twenty-five soldiers (72 ± 10 kg) (Mean ± SD) completed the march in 09:11 ± 00:43 (hr:min). Participants consumed 736 ± 259 ml/h of water and lost 2.8 ± 0.9 kg (4.0% ± 1.4%, P < 0.05) of body mass. Significant (pre-march vs. post-march; P < 0.05) decreases in serum [Na+] (141 mmol/L vs. 136 mmol/L), plasma osmolality (303 mOsmol/kg H2O vs. 298 mOsmol/kg H2O), and serum creatinine (111 μmol/L vs. 101 μmol/L) and urine [Na+] (168 mmol/L vs. 142 mmol/L), as well as significant increases in plasma AVP (2 pg/ml vs. 11 pg/ml), plasma CK (1423 U/L vs. 3894 U/L) and urine osmolality (1035 mOsmol/kg H2O vs. 1097 mOsmol/kg H2O) were found. The soldier (72 kg) with the lowest post-exercise sodium level completed the march in 08:38. He drank 800 ml/h, lost 2% body mass, and demonstrated (pre-post) increases in plasma osmolality (294-314 mOsmol/kg H2O), BUN (20-30 mg/dl), AVP (2-16 pg/ml) and PV (41%). His urine osmolality decreased from 1114 mOsmol/kg H2O to 1110 mOsmol/kg H2O. No participants finished the route-march with a serum [Na+] indicating hypernatremia (range, 134-143 mmol/L). CONCLUSIONS Ad libitum drinking resulted in 4% body mass loss with a 2 mmol/L serum [Na+] reduction in conjunction with high urine osmolality (> 1000 mOsmol/kg H2O) and plasma AVP. No single hydration strategy likely prevents EAH, but hypernatremia (cellular dehydration) was not seen despite > 2% body mass losses and high urine osmolality.
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Affiliation(s)
- Heinrich W Nolte
- Movement Physiology Research Laboratory, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Kim Nolte
- Division Biokinetics and Sport Science, Department of Physiology, University of Pretoria, Pretoria, South Africa
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Abstract
In humans, thirst tends to be alleviated before complete rehydration is achieved. When sweating rates are high and ad libitum fluid consumption is not sufficient to replace sweat losses, a cumulative loss in body water results. Body mass losses of 2% or greater take time to accumulate. Dehydration of ≥ 2% body mass is associated with impaired thermoregulatory function, elevated cardiovascular strain and, in many conditions (e.g., warmer, longer, more intense), impaired aerobic exercise performance. Circumstances where planned drinking is optimal include longer duration activities of > 90 min, particularly in the heat; higher-intensity exercise with high sweat rates; exercise where performance is a concern; and when carbohydrate intake of 1 g/min is desired. Individuals with high sweat rates and/or those concerned with exercise performance should determine sweat rates under conditions (exercise intensity, pace) and environments similar to that anticipated when competing and tailor drinking to prevent body mass losses > 2%. Circumstances where drinking to thirst may be sufficient include short duration exercise of < 1 h to 90 min; exercise in cooler conditions; and lower-intensity exercise. It is recommended to never drink so much that weight is gained.
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Affiliation(s)
- Robert W Kenefick
- Thermal and Mountain Medicine Division, US Army Research Institute, Natick, MA, USA.
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Ad libitum drinking adequately supports hydration during 2 h of running in different ambient temperatures. Eur J Appl Physiol 2018; 118:2687-2697. [PMID: 30267225 DOI: 10.1007/s00421-018-3996-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 09/18/2018] [Indexed: 01/06/2023]
Abstract
PURPOSE To examine if ad libitum drinking will adequately support hydration during exertional heat stress. METHODS Ten endurance-trained runners ran for 2 h at 60% of maximum oxygen uptake under different conditions. Participants drank water ad libitum during separate trials at mean ambient temperatures of 22 °C, 30 °C and 35 °C. Participants also completed three trials at a mean ambient temperature of 35 °C while drinking water ad libitum in all trials, and with consumption of programmed glucose or whey protein hydrolysate solutions to maintain euhydration in two of these trials. Heart rate, oxygen uptake, rectal temperature, perceived effort, and thermal sensation were monitored, and nude body mass, hemoglobin, hematocrit, and plasma osmolality were measured before and after exercise. Water and mass balance equations were used to calculate hydration-related variables. RESULTS Participants adjusted their ad libitum water intake so that the same decrease in body mass (1.1-1.2 kg) and same decrease in body water (0.8-0.9 kg) were observed across the range of ambient temperatures which yielded significant differences (p < .001) in sweat loss. Overall, water intake and total water gain replaced 57% and 66% of the water loss, respectively. The loss in body mass and body water associated with ad libitum drinking resulted in no alteration in physiological and psychophysiological variables compared with the condition when hydration was nearly fully maintained (0.3 L body water deficit) relative to pre-exercise status from programmed drinking. CONCLUSIONS Ad libitum drinking is an appropriate strategy for supporting hydration during running for 2 h duration under hot conditions.
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Barwood MJ, Goodall S, Bateman J. The effect of hot and cold drinks on thermoregulation, perception, and performance: the role of the gut in thermoreception. Eur J Appl Physiol 2018; 118:2643-2654. [PMID: 30203296 DOI: 10.1007/s00421-018-3987-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/27/2018] [Indexed: 02/04/2023]
Abstract
PURPOSE Hot compared to cold drinks alter sweating responses during very low intensity exercise in temperate conditions. The thermoregulatory, perceptual, and performance effects of hot compared to cold drinks in hot, dry conditions during high-intensity exercise have not been examined. METHOD Ten participants [mean ± SD characteristics age 25 ± 5 years, height 1.81 ± 0.07 m, body mass 73.5 ± 10.6 kg, maximal power output (PMax) 350 ± 41 W] completed two conditions, where they drank four boluses (ingested at - 9, 15, 30, and 45 min, respectively) of 3.2 mL kg- 1 (~ 960 mL total) of either a COLD (5.3 °C) or a HOT drink (49.0 °C), which were contrasted to a no-drink CONTROL. They cycled for 60-min [55% PMax in hot (34.4 °C) dry (34% RH)] ambient conditions followed by a test to exhaustion (TTE; 80% PMax). The thermoregulatory, performance, and perceptual implications of drink temperature were measured. RESULTS TTE was worse in the CONTROL (170 ± 132 s) than the COLD drink (371 ± 272 s; p = 0.021) and HOT drink conditions (367 ± 301 s; p = 0.038) which were not different (p = 0.965). Sweat responses [i.e., reflex changes in mean skin temperature (Tmsk) and galvanic skin conductance] indicated transient reductions in sweating response after COLD drink ingestion. The COLD drink improved thermal comfort beyond the transient changes in sweating. CONCLUSION Only COLD drink ingestion changed thermoregulation, but improved perceptual response. Accordingly, we conclude a role for gut thermoreception in thermal perception during exercise in hot, dry conditions.
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Affiliation(s)
- Martin J Barwood
- Department of Sport, Health and Nutrition, Leeds Trinity University, Brownberrie Lane, Horsforth, Leeds, LS18 5HD, UK.
| | - Stuart Goodall
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Northumberland Road, Newcastle upon Tyne, UK
| | - Jon Bateman
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Northumberland Road, Newcastle upon Tyne, UK
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ADAMS JD, SEKIGUCHI YASUKI, SUH HYUNGYU, SEAL ADAMD, SPRONG CAMERONA, KIRKLAND TRACIEW, KAVOURAS STAVROSA. Dehydration Impairs Cycling Performance, Independently of Thirst: A Blinded Study. Med Sci Sports Exerc 2018; 50:1697-1703. [DOI: 10.1249/mss.0000000000001597] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Buoite Stella A, Yardley J, Francescato MP, Morrison SA. Fluid Intake Habits in Type 1 Diabetes Individuals during Typical Training Bouts. ANNALS OF NUTRITION AND METABOLISM 2018; 73:10-18. [PMID: 29843124 DOI: 10.1159/000489823] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 04/30/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND/AIMS Hyperglycemia may influence the hydration status in diabetic individuals. During exercise, type 1 diabetes mellitus (T1DM) individuals may be challenged by a higher risk of dehydration due to a combination of fluid losses from sweat and increased urine output via glycosuria. So far, no study has characterised spontaneous fluid intake in T1DM individuals during active trainings. METHODS A validated questionnaire was used to assess T1DM participants' diabetes therapy, sports characteristics and fluid intake during training; results were then compared to an age- and sport-matched sample of non-diabetic individuals. RESULTS Ninety individuals completed the survey (n = 45 T1DM individuals, n = 45 matched controls). A proportion of T1DM -individuals reported blood glucose levels greater than 10.0 mmol at both the start (28.9%) and end (24.4%) of the exercise. The mean self-reported fluid intake was greater in T1DM (0.60 ± 0.47 L·h-1) compared to that of the control (0.37 ± 0.28 L·h-1, p < 0.05). In spite of drinking fluid volumes in line with international guidelines, 84.4% of those with T1DM reported that they were still feeling thirsty at the end of their training session. CONCLUSIONS T1DM individuals self-report spontaneously consuming fluid adequate volumes suggested by sport nutrition guidelines for non-diabetic athletes. Discrepancies in the T1DM subjectively reported feelings of thirst suggest that more education on hydration during exercise is needed for this population to adequately compensate for elevated blood glucose levels. It remains to be established whether fluid volumes suggested for healthy athletes are adequate for maintaining euhydration in T1DM patients due to their altered diuresis.
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Affiliation(s)
- Alex Buoite Stella
- Department of Medicine, University of Udine, Udine, Italy.,Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy
| | - Jane Yardley
- Department of Social Sciences, Augustana Campus, University of Alberta, Edmonton, Alberta, Canada
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20
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Hayakawa NMM, Reis RCG, Oliveira JPLD, Pereira JDAR, Abreu WCD. Drinking to thirst influences fluid replacement in adolescents judokas. MOTRIZ: REVISTA DE EDUCACAO FISICA 2018. [DOI: 10.1590/s1980-6574201800010007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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21
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Hoffman MD, Cotter JD, Goulet ÉD, Laursen PB. REBUTTAL from "Yes". Wilderness Environ Med 2017; 27:198-200. [PMID: 27291701 DOI: 10.1016/j.wem.2016.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 04/10/2016] [Accepted: 04/11/2016] [Indexed: 12/30/2022]
Affiliation(s)
- Martin D Hoffman
- Department of Physical Medicine & Rehabilitation, Department of Veterans Affairs, Northern California Health Care System, and University of California Davis Medical Center, Sacramento, CA.
| | - James D Cotter
- Exercise and Environmental Physiology, School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand(Dr Cotter)?>
| | - Éric D Goulet
- Research Centre on Aging, Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Quebec, Canada
| | - Paul B Laursen
- High Performance Sport New Zealand, and Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, Aukland, Auckland, New Zealand
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McDermott BP, Anderson SA, Armstrong LE, Casa DJ, Cheuvront SN, Cooper L, Kenney WL, O'Connor FG, Roberts WO. National Athletic Trainers' Association Position Statement: Fluid Replacement for the Physically Active. J Athl Train 2017; 52:877-895. [PMID: 28985128 PMCID: PMC5634236 DOI: 10.4085/1062-6050-52.9.02] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE To present evidence-based recommendations that promote optimized fluid-maintenance practices for physically active individuals. BACKGROUND Both a lack of adequate fluid replacement (hypohydration) and excessive intake (hyperhydration) can compromise athletic performance and increase health risks. Athletes need access to water to prevent hypohydration during physical activity but must be aware of the risks of overdrinking and hyponatremia. Drinking behavior can be modified by education, accessibility, experience, and palatability. This statement updates practical recommendations regarding fluid-replacement strategies for physically active individuals. RECOMMENDATIONS Educate physically active people regarding the benefits of fluid replacement to promote performance and safety and the potential risks of both hypohydration and hyperhydration on health and physical performance. Quantify sweat rates for physically active individuals during exercise in various environments. Work with individuals to develop fluid-replacement practices that promote sufficient but not excessive hydration before, during, and after physical activity.
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Katch RK, Scarneo SE, Adams WM, Armstrong LE, Belval LN, Stamm JM, Casa DJ. Top 10 Research Questions Related to Preventing Sudden Death in Sport and Physical Activity. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2017; 88:251-268. [PMID: 28805553 DOI: 10.1080/02701367.2017.1342201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Participation in organized sport and recreational activities presents an innate risk for serious morbidity and mortality. Although death during sport or physical activity has many causes, advancements in sports medicine and evidence-based standards of care have allowed clinicians to prevent, recognize, and treat potentially fatal injuries more effectively. With the continual progress of research and technology, current standards of care are evolving to enhance patient outcomes. In this article, we provided 10 key questions related to the leading causes and treatment of sudden death in sport and physical activity, where future research will support safer participation for athletes and recreational enthusiasts. The current evidence indicates that most deaths can be avoided when proper strategies are in place to prevent occurrence or provide optimal care.
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Kupchak BR, Kazman JB, Vingren JL, Levitt DE, Lee EC, Williamson KH, Armstrong LE, Deuster PA. Blood Hemostatic Changes During an Ultraendurance Road Cycling Event in a Hot Environment. Wilderness Environ Med 2017; 28:197-206. [DOI: 10.1016/j.wem.2017.05.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 05/03/2017] [Accepted: 05/05/2017] [Indexed: 10/19/2022]
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Chlíbková D, Nikolaidis PT, Rosemann T, Knechtle B, Bednář J. Reported Hydration Beliefs and Behaviors without Effect on Plasma Sodium in Endurance Athletes. Front Physiol 2017; 8:259. [PMID: 28512433 PMCID: PMC5411442 DOI: 10.3389/fphys.2017.00259] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/10/2017] [Indexed: 11/13/2022] Open
Abstract
Purpose: Little information is available on the association of hydration beliefs and behaviors in endurance athletes and exercise-associated hyponatremia (EAH). The aim of the present study was to determine hydration beliefs and behaviors in endurance athletes. Method: A 100 and 38 recreational athletes [107 mountain bikers (MTBers) and 31 runners] competing in seven different endurance and ultra-endurance races completed pre- and post-race questionnaires, and a subgroup of 113 (82%) participants (82 MTBers and 31 runners) also provided their blood samples. Result: More than half of the participants had some pre-race (59%), mid-race (58%), and post-race (55%) drinking plan. However, the participants simultaneously reported that temperature (66%), thirst (52%), and plan (37%) affected their drinking behavior during the race. More experienced (years of active sport: p = 0.002; number of completed races: p < 0.026) and trained (p = 0.024) athletes with better race performance (p = 0.026) showed a more profound knowledge of EAH, nevertheless, this did not influence their planned hydration, reported fluid intake, or post-race plasma sodium. Thirteen (12%) hyponatremic participants did not differ in their hydration beliefs, race behaviors, or reported fluid intake from those without post-race EAH. Compared to MTBers, runners more often reported knowledge of the volumes of drinks offered at fluid stations (p < 0.001) and information on how much to drink pre-race (p < 0.001), yet this was not associated with having a drinking plan (p > 0.05). MTBers with hydration information planned more than other MTBers (p = 0.004). In comparison with runners, more MTBers reported riding with their own fluids (p < 0.001) and planning to drink at fluid stations (p = 0.003). On the whole, hydration information was positively associated with hydration planning (n = 138) (p = 0.003); nevertheless, the actual reported fluid intake did not differ between the group with and without hydration information, or with and without a pre-race drinking plan (p > 0.05). Conclusion: In summary, hydration beliefs and behaviors in the endurance athletes do not appear to affect the development of asymptomatic EAH.
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Affiliation(s)
- Daniela Chlíbková
- Centre of Sports Activities, Brno University of TechnologyBrno, Czechia
| | | | - Thomas Rosemann
- Institute of Primary Care, University of ZurichZurich, Switzerland
| | - Beat Knechtle
- Institute of Primary Care, University of ZurichZurich, Switzerland.,Gesundheitszentrum St. GallenSt. Gallen, Switzerland
| | - Josef Bednář
- Faculty of Mechanical Engineering, Brno University of TechnologyBrno, Czechia
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Bargh MJ, King RFGJ, Gray MP, Jones B. Why do team-sport athletes drink fluid in excess when exercising in cool conditions? Appl Physiol Nutr Metab 2016; 42:271-277. [PMID: 28145733 DOI: 10.1139/apnm-2016-0445] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study assessed the potential physiological and perceptual drivers of fluid intake and thirst sensation during intermittent exercise. Ten male rugby players (17 ± 1 years, stature: 179.1 ± 4.2 cm, body mass (BM): 81.9 ± 8.1 kg) participated in six 6-min small-sided games, interspersed with 2 min rest, where fluid intake was ad libitum during rest periods. Pre- and postmeasurements of BM, subjective ratings (thirst, thermal comfort, thermal sensation, mouth dryness), plasma osmolality (POsm), serum sodium concentration (S[Na+]), haematocrit and haemoglobin (to calculate plasma volume change; PV) were taken. Fluid intake was measured during rest periods. BM change was -0.17 ± 0.59% and fluid intake was 0.88 ± 0.38 L. Pre- to post-POsm decreased (-3.1 ± 2.3 mOsm·kg-1; p = 0.002) and S[Na+] remained similar (-0.3 ± 0.7 mmol·L-1, p = 0.193). ΔPV was 5.84 ± 3.65%. Fluid intake displayed a relationship with pre-POsm (r = -0.640, p = 0.046), prethermal comfort (r = 0.651; p = -0.041), ΔS[Na+] (r = 0.816, p = 0.004), and ΔPV (r = 0.740; p = 0.014). ΔThirst sensation displayed a relationship with premouth dryness (r = 0.861, p = 0.006) and Δmouth dryness (r = 0.878, p = 0.004). Yet a weak positive relationship between Δthirst sensation and fluid intake was observed (r = 0.085, p = 0.841). These data observed in an ambient temperature of 13.6 ± 0.9 °C, suggest team-sport athletes drink in excess of fluid homeostasis requirements and thirst sensation in cool conditions; however, this was not influenced by thermal discomfort.
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Affiliation(s)
- Melissa J Bargh
- Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.,Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS
| | - Roderick F G J King
- Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.,Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS
| | - Michael P Gray
- Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.,Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS
| | - Ben Jones
- Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS.,Institute of Sport, Physical Activity and Leisure, G05 Carnegie Hall, Headingley Campus, Leeds Beckett University, Leeds, W. Yorkshire, United Kingdom LS6 3QS
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27
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Cutrufello PT, Dixon CB, Zavorsky GS. Hydration assessment among marathoners using urine specific gravity and bioelectrical impedance analysis. Res Sports Med 2016; 24:234-42. [PMID: 27373703 DOI: 10.1080/15438627.2016.1202831] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The present study examined the relationship between urine specific gravity (Usg), body mass (BM) and bioelectrical impedance determined variables [total body water (TBW), per cent TBW and impedance values] before and after a marathon (n = 25 men; 10 women). A significant reduction in BM (pre: 71.2 ± 12.4 kg; post: 69.6 ± 12.0 kg; p < 0.001) and an increase in Usg (pre: 1.009 ± 0.007; post: 1.018 ± 0.009; p < 0.001) was observed post-race. TBW was not significantly decreased (pre: 42.7 ± 8.0 kg; post: 42.4 ± 7.7 kg) while per cent TBW significantly increased post-race (pre: 60.0 ± 3.9%; post: 60.8 ± 3.8%; p < 0.001). Impedance values were significantly greater post-race (pre: 3288 ± 482; post: 3416 ± 492 Ω; p < 0.001). There was no correlation between the change in Usg and the change in BM or any of the bioelectrical impedance determined variables. On average, BM, Usg and impedance values appear to express changes in hydration; however, the observed changes among these variables for a given individual appear to be inconsistent with one another.
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Affiliation(s)
- Paul T Cutrufello
- a Exercise Science and Sport , The University of Scranton , Scranton , PA , USA
| | - Curt B Dixon
- b Health Sciences Dept , Lock Haven University , Lock Haven , PA , USA
| | - Gerald S Zavorsky
- c Department of Health and Sports Sciences , University of Louisville , Louisville , KY , USA
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COUNTERVIEW: Is Drinking to Thirst Adequate to Appropriately Maintain Hydration Status During Prolonged Endurance Exercise? No. Wilderness Environ Med 2016; 27:195-8. [DOI: 10.1016/j.wem.2016.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 03/09/2016] [Accepted: 03/09/2016] [Indexed: 11/24/2022]
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Lopez RM, Casa DJ, Jensen KA, Stearns RL, DeMartini JK, Pagnotta KD, Roti MW, Armstrong LE, Maresh CM. Comparison of Two Fluid Replacement Protocols During a 20-km Trail Running Race in the Heat. J Strength Cond Res 2016; 30:2609-16. [PMID: 26840437 DOI: 10.1519/jsc.0000000000001359] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lopez, RM, Casa, DJ, Jensen, K, Stearns, RL, DeMartini, JK, Pagnotta, KD, Roti, MW, Armstrong, LE, and Maresh, CM. Comparison of two fluid replacement protocols during a 20-km trail running race in the heat. J Strength Cond Res 30(9): 2609-2616, 2016-Proper hydration is imperative for athletes striving for peak performance and safety, however, the effectiveness of various fluid replacement strategies in the field setting is unknown. The purpose of this study was to investigate how two hydration protocols affect physiological responses and performance during a 20-km trail running race. A randomized, counter-balanced, crossover design was used in a field setting (mean ± SD: WBGT 28.3 ± 1.9° C). Well-trained male (n = 8) and female (n = 5) runners (39 ± 14 years; 175 ± 9 cm; 67.5 ± 11.1 kg; 13.4 ± 4.6% BF) completed two 20-km trail races (5 × 4-km loop) with different water hydration protocols: (a) ad libitum (AL) consumption and (b) individualized rehydration (IR). Data were analyzed using repeated measures ANOVA. Paired t-tests compared pre-race-post-race measures. Main outcome variables were race time, heart rate (HR), gastrointestinal temperature (TGI), fluid consumed, percent body mass loss (BML), and urine osmolality (Uosm). Race times between groups were similar. There was a significant condition × time interaction (p = 0.048) for HR, but TGI was similar between conditions. Subjects replaced 30 ± 14% of their water losses in AL and 64 ± 16% of their losses in IR (p < 0.001). Ad libitum trial experienced greater BML (-2.6 ± 0.5%) compared with IR (-1.3 ± 0.5%; p < 0.001). Pre-race to post-race Uosm differences existed between AL (-273 ± 146 mOsm) and IR (-145 ± 215 mOsm, p = 0.032). In IR, runners drank twice as much fluid than AL during the 20-km race, leading to > 2% BML in AL. Ad libitum drinking resulted in 1.3% greater BML over the 20-km race, which resulted in no thermoregulatory or performance differences from IR.
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Affiliation(s)
- Rebecca M Lopez
- 1Morsani College of Medicine, University of South Florida, Tampa, Florida; 2Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, Connecticut; 3College of Health Professions, Sacred Heart University, Fairfield, CT; 4Department of Kinesiology, Temple University, Philadelphia, Pennsylvania; 5Department of Movement Science, Sport & Leisure Studies, Westfield State University, Westfield, Massachusetts; and 6Department of Human Sciences, Ohio State University, Columbus, Ohio
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Hew-Butler T, Rosner MH, Fowkes-Godek S, Dugas JP, Hoffman MD, Lewis DP, Maughan RJ, Miller KC, Montain SJ, Rehrer NJ, Roberts WO, Rogers IR, Siegel AJ, Stuempfle KJ, Winger JM, Verbalis JG. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med 2015; 25:303-20. [PMID: 26102445 DOI: 10.1097/jsm.0000000000000221] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Tamara Hew-Butler
- *Exercise Science Program, Oakland University, Rochester, Michigan; †Division of Nephrology, University of Virginia Health System, Charlottesville, Virginia; ‡Department of Sports Medicine, West Chester University, West Chester, Pennsylvania; §The Vitality Group, Chicago, Illinois; ¶Department of Physical Medicine and Rehabilitation, VA Northern California Health Care System and University of California Davis, Sacramento, California; ‖Family Medicine Residency Program, Via Christi Hospitals Wichita, Inc, Wichita, Kansas; **Department of Sport and Exercise Nutrition, Loughborough University, Leicestershire, United Kingdom; ††Athletic Training Program, Central Michigan University, Mount Pleasant, Michigan; ‡‡Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts; §§School of Physical Education, Sport and Exercise Science, University of Otago, Dunedin, New Zealand; ¶¶Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota; ‖‖Department of Emergency Medicine, St John of God Murdoch Hospital and University of Notre Dame, Perth, Western Australia; ***Department of Internal Medicine, Harvard Medical School, Boston, Massachusetts; †††Health Sciences Department, Gettysburg College, Gettysburg, Pennsylvania; ‡‡‡Department of Family Medicine, Loyola University Chicago Stritch School of Medicine, Chicago, Illinois; and §§§Department of Endocrinology and Metabolism, Georgetown University Medical Center, Washington, District of Columbia
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Armstrong LE, Johnson EC, McKenzie AL, Ellis LA, Williamson KH. Ultraendurance Cycling in a Hot Environment. J Strength Cond Res 2015; 29:869-76. [DOI: 10.1519/jsc.0000000000000822] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Moyen NE, Ganio MS, Wiersma LD, Kavouras SA, Gray M, McDERMOTT BRENDONP, Adams J, Binns AP, Judelson DA, McKENZIE AMYL, Johnson EC, Muñoz CX, Kunces LJ, Armstrong LE. Hydration status affects mood state and pain sensation during ultra-endurance cycling. J Sports Sci 2015; 33:1962-9. [DOI: 10.1080/02640414.2015.1021275] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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