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Suarez-Ortegón MF, Zea-León MDP, Astudillo-Gironza AM, Garzón S, Portela GF, Villarreal-Nieto OD. Sweat Rate, Sweat Sodium Losses, and Body Composition in Professional Male Soccer Players in Southwest Colombia. MEDICINA (KAUNAS, LITHUANIA) 2024; 60:113. [PMID: 38256373 PMCID: PMC10819496 DOI: 10.3390/medicina60010113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Revised: 01/02/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024]
Abstract
Background and Objective: Dehydration and hyperhydration impact athletes' performance. Exploring the fluid balance concerning body composition might help estimate individual hydration requirements. This area of research, particularly regarding sodium losses, has been relatively understudied. We evaluated the sweat rate (SR), sweat sodium losses, and their relationship with body composition in professional soccer players in Cali, Colombia. Materials and Methods: Thirty-two male players, aged 24.3 (±5.2) years, from the Colombian main soccer league, underwent high-intensity training at 32 °C (with a relative humidity of 79%). The outcome variables included SR, calculated using weight loss and fluid intake; forearm sweat sodium concentration (FSCC), measured through the direct ion-selective electrode method; and estimated the predicted whole sweat sodium loss (PWSSL) in mmol. Predictor variables (body mass, fat, and muscle masses) were estimated using the Deborah Kerr anthropometry method. The association between predictors and outcomes was assessed using linear regression. Results: The mean FSCC, PWSSL, and SR were 26.7 ± 11.3 mmol/L, 43 ± 15.9 mmol/L, and 1.7 ± 0.5 L/h, respectively. Body mass positively predicted FSCC in unadjusted and age/fat-mass-adjusted models [Beta 1.28, 95% confidence interval (CI) 0.39-2.18, p = 0.006], and continued related to FSCC after adjustment for muscle mass with marginal significance [Beta 0.85, 95% CI -0.02 to 1.73, p = 0.056]. Muscle mass was associated with the PWSSL in unadjusted and age/fat-mass-adjusted models [Beta 2.42, 95% CI 0.58-4.26, p = 0.012] and sustained an association with marginal statistical significance after adjustment for body mass [Beta 1.86, 95% CI -0.35 to 4.09, p = 0.097]. Conclusions: Under hot tropical weather conditions, FSCC was relatively low among the players. Body mass was better associated with the FSSC, and muscle mass better related to the PWSSL. Body and muscle masses could be regarded as potential factors to be explored in the estimation of individual sodium needs. However, further studies are required to validate and contrast our findings.
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Affiliation(s)
- Milton Fabian Suarez-Ortegón
- Departamento de Alimentación y Nutrición, Facultad de Ciencias de La Salud, Pontificia Universidad Javeriana Seccional Cali, Cali 760021, Colombia;
| | - Maria del Pilar Zea-León
- Departamento de Alimentación y Nutrición, Facultad de Ciencias de La Salud, Pontificia Universidad Javeriana Seccional Cali, Cali 760021, Colombia;
| | | | - Silverio Garzón
- Departamento de Ciencias Básicas, Facultad de Ciencias de La Salud, Pontificia Universidad Javeriana Seccional Cali, Cali 760021, Colombia;
| | | | - Oscar Daniel Villarreal-Nieto
- Departamento de Alimentación y Nutrición, Facultad de Ciencias de La Salud, Pontificia Universidad Javeriana Seccional Cali, Cali 760021, Colombia;
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 4: evolution, thermal adaptation and unsupported theories of thermoregulation. Eur J Appl Physiol 2024; 124:147-218. [PMID: 37796290 DOI: 10.1007/s00421-023-05262-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 06/13/2023] [Indexed: 10/06/2023]
Abstract
This review is the final contribution to a four-part, historical series on human exercise physiology in thermally stressful conditions. The series opened with reminders of the principles governing heat exchange and an overview of our contemporary understanding of thermoregulation (Part 1). We then reviewed the development of physiological measurements (Part 2) used to reveal the autonomic processes at work during heat and cold stresses. Next, we re-examined thermal-stress tolerance and intolerance, and critiqued the indices of thermal stress and strain (Part 3). Herein, we describe the evolutionary steps that endowed humans with a unique potential to tolerate endurance activity in the heat, and we examine how those attributes can be enhanced during thermal adaptation. The first of our ancestors to qualify as an athlete was Homo erectus, who were hairless, sweating specialists with eccrine sweat glands covering almost their entire body surface. Homo sapiens were skilful behavioural thermoregulators, which preserved their resource-wasteful, autonomic thermoeffectors (shivering and sweating) for more stressful encounters. Following emigration, they regularly experienced heat and cold stress, to which they acclimatised and developed less powerful (habituated) effector responses when those stresses were re-encountered. We critique hypotheses that linked thermoregulatory differences to ancestry. By exploring short-term heat and cold acclimation, we reveal sweat hypersecretion and powerful shivering to be protective, transitional stages en route to more complete thermal adaptation (habituation). To conclude this historical series, we examine some of the concepts and hypotheses of thermoregulation during exercise that did not withstand the tests of time.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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3
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 2: physiological measurements. Eur J Appl Physiol 2023; 123:2587-2685. [PMID: 37796291 DOI: 10.1007/s00421-023-05284-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 07/14/2023] [Indexed: 10/06/2023]
Abstract
In this, the second of four historical reviews on human thermoregulation during exercise, we examine the research techniques developed by our forebears. We emphasise calorimetry and thermometry, and measurements of vasomotor and sudomotor function. Since its first human use (1899), direct calorimetry has provided the foundation for modern respirometric methods for quantifying metabolic rate, and remains the most precise index of whole-body heat exchange and storage. Its alternative, biophysical modelling, relies upon many, often dubious assumptions. Thermometry, used for >300 y to assess deep-body temperatures, provides only an instantaneous snapshot of the thermal status of tissues in contact with any thermometer. Seemingly unbeknownst to some, thermal time delays at some surrogate sites preclude valid measurements during non-steady state conditions. To assess cutaneous blood flow, immersion plethysmography was introduced (1875), followed by strain-gauge plethysmography (1949) and then laser-Doppler velocimetry (1964). Those techniques allow only local flow measurements, which may not reflect whole-body blood flows. Sudomotor function has been estimated from body-mass losses since the 1600s, but using mass losses to assess evaporation rates requires precise measures of non-evaporated sweat, which are rarely obtained. Hygrometric methods provide data for local sweat rates, but not local evaporation rates, and most local sweat rates cannot be extrapolated to reflect whole-body sweating. The objective of these methodological overviews and critiques is to provide a deeper understanding of how modern measurement techniques were developed, their underlying assumptions, and the strengths and weaknesses of the measurements used for humans exercising and working in thermally challenging conditions.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- College of Human Ecology, Research Institute of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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4
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Turner O, Mitchell N, Ruddock A, Purvis A, Ranchordas MK. Fluid Balance, Sodium Losses and Hydration Practices of Elite Squash Players during Training. Nutrients 2023; 15:nu15071749. [PMID: 37049589 PMCID: PMC10096645 DOI: 10.3390/nu15071749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 03/30/2023] [Accepted: 04/01/2023] [Indexed: 04/07/2023] Open
Abstract
Elite squash players are reported to train indoors at high volumes and intensities throughout a microcycle. This may increase hydration demands, with hypohydration potentially impairing many key performance indicators which characterise elite squash performance. Consequently, the main aim of this study was to quantify the sweat rates and sweat [Na+] of elite squash players throughout a training session, alongside their hydration practices. Fourteen (males = seven; females = seven) elite or world class squash player’s fluid balance, sweat [Na+] and hydration practices were calculated throughout a training session in moderate environmental conditions (20 ± 0.4 °C; 40.6 ± 1% RH). Rehydration practices were also quantified post-session until the players’ next training session, with some training the same day and some training the following day. Players had a mean fluid balance of −1.22 ± 1.22% throughout the session. Players had a mean sweat rate of 1.11 ± 0.56 L·h−1, with there being a significant difference between male and female players (p < 0.05), and a mean sweat (Na+) of 46 ± 12 mmol·L−1. Players training the following day were able to replace fluid and sodium losses, whereas players training again on the same day were not. These data suggest the variability in players hydration demands and highlight the need to individualise hydration strategies, as well as training prescription, to ensure players with high hydration demands have ample time to optimally rehydrate.
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Affiliation(s)
- Ollie Turner
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
- English Institute of Sport, Manchester M11 3BS, UK
| | | | - Alan Ruddock
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
| | - Alison Purvis
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
| | - Mayur K. Ranchordas
- Academy of Sport & Physical Activity, Sheffield Hallam University, Sheffield S10 2BP, UK
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5
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Tarnowski CA, Rollo I, Carter JM, Lizarraga-Dallo MA, Oliva MP, Clifford T, James LJ, Randell RK. Fluid Balance and Carbohydrate Intake of Elite Female Soccer Players during Training and Competition. Nutrients 2022; 14:nu14153188. [PMID: 35956363 PMCID: PMC9370343 DOI: 10.3390/nu14153188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 07/27/2022] [Accepted: 08/01/2022] [Indexed: 02/06/2023] Open
Abstract
This study examined sweat rate, sweat sodium concentration [Na+], and ad-libitum carbohydrate and fluid intakes in elite female soccer players during training (n = 19) and a match (n = 8); eight completed both for comparisons. Body mass (kg) was obtained before and after exercise to calculate sweat rate. The sweat [Na+] was determined from absorbent patches on the thigh or back. Sweat rate, percentage body mass change, and sweat [Na+] for 19 players during training were 0.47 ± 0.19 L·h−1, +0.19 ± 0.65%, and 28 ± 10 mmol·L−1, respectively. Sweat rate was higher during a match (0.98 ± 0.34 L·h−1) versus training (0.49 ± 0.26 L·h−1, p = 0.007). Body mass losses were greater post-match (−1.12 ± 0.86%) than training (+0.29 ± 0.34%, p = 0.003). Sweat [Na+] was similar for training (29 ± 9 mmol·L−1) and a match (35 ± 9 mmol·L−1) (p = 0.215). There were no differences in match versus training carbohydrate intakes (2.0 ± 2.3 g·h−1, 0.9 ± 1.5 g·h−1, respectively, p = 0.219) or fluid intakes (0.71 ± 0.30 L·h−1, 0.53 ± 0.21 L·h−1, respectively, p = 0.114). In conclusion, female soccer players’ sweat rates were higher during a match than during training, and carbohydrate intakes were below recommendations for matches and training.
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Affiliation(s)
- Caroline A. Tarnowski
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire LE4 1ET, UK; (I.R.); (J.M.C.); (R.K.R.)
- Correspondence:
| | - Ian Rollo
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire LE4 1ET, UK; (I.R.); (J.M.C.); (R.K.R.)
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; (T.C.); (L.J.J.)
| | - James M. Carter
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire LE4 1ET, UK; (I.R.); (J.M.C.); (R.K.R.)
| | | | - Mireia Porta Oliva
- FC Barcelona Medical Department, FC Barcelona, 08014 Barcelona, Spain; (M.A.L.-D.); (M.P.O.)
| | - Tom Clifford
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; (T.C.); (L.J.J.)
| | - Lewis J. James
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; (T.C.); (L.J.J.)
| | - Rebecca K. Randell
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire LE4 1ET, UK; (I.R.); (J.M.C.); (R.K.R.)
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK; (T.C.); (L.J.J.)
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6
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de Sousa MV, Lundsgaard AM, Christensen PM, Christensen L, Randers MB, Mohr M, Nybo L, Kiens B, Fritzen AM. Nutritional optimization for female elite football players-topical review. Scand J Med Sci Sports 2021; 32 Suppl 1:81-104. [PMID: 34865242 DOI: 10.1111/sms.14102] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/13/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022]
Abstract
Women's football is an intermittent sport characterized by frequent intense actions throughout the match. The high number of matches with limited recovery time played across a long competitive season underlines the importance of nutritional strategies to meet these large physical demands. In order to maximize sport performance and maintain good health, energy intake must be optimal. However, a considerable proportion of female elite football players does not have sufficient energy intake to match the energy expenditure, resulting in low energy availability that might have detrimental physiologic consequences and impair performance. Carbohydrates appear to be the primary fuel covering the total energy supply during match-play, and female elite football players should aim to consume sufficient carbohydrates to meet the requirements of their training program and to optimize the replenishment of muscle glycogen stores between training bouts and matches. However, several macro- and micronutrients are important for ensuring sufficient energy and nutrients for performance optimization and for overall health status in female elite football players. The inadequacy of macro-and micronutrients in the diet of these athletes may impair performance and training adaptations, and increase the risk of health disorders, compromising the player's professional career. In this topical review, we present knowledge and relevant nutritional recommendations for elite female football players for the benefit of sports nutritionists, dietitians, sports scientists, healthcare specialists, and applied researchers. We focus on dietary intake and cover the most pertinent topics in sports nutrition for the relevant physical demands in female elite football players as follows: energy intake, macronutrient and micronutrient requirements and optimal composition of the everyday diet, nutritional and hydration strategies to optimize performance and recovery, potential ergogenic effects of authorized relevant supplements, and future research considerations.
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Affiliation(s)
- Maysa V de Sousa
- Laboratory of Medical Investigation, LIM-18, Endocrinology Division, School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Anne-Marie Lundsgaard
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | | | - Lars Christensen
- Department of Nutrition, Exercise and Sports, Section of Obesity Research, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Morten B Randers
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), University of Southern Denmark, Odense, Denmark.,School of Sport Sciences, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Magni Mohr
- Department of Sports Science and Clinical Biomechanics, SDU Sport and Health Sciences Cluster (SHSC), University of Southern Denmark, Odense, Denmark.,Centre of Health Science, Faculty of Health, University of the Faroe Islands, Tórshavn, Faroe Islands
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, Section of Integrative Physiology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Bente Kiens
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Andreas M Fritzen
- Department of Nutrition, Exercise and Sports, Section of Molecular Physiology, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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Randell RK, Clifford T, Drust B, Moss SL, Unnithan VB, De Ste Croix MBA, Datson N, Martin D, Mayho H, Carter JM, Rollo I. Physiological Characteristics of Female Soccer Players and Health and Performance Considerations: A Narrative Review. Sports Med 2021; 51:1377-1399. [PMID: 33844195 PMCID: PMC8222040 DOI: 10.1007/s40279-021-01458-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2021] [Indexed: 12/18/2022]
Abstract
Female soccer has seen a substantial rise in participation, as well as increased financial support from governing bodies over the last decade. Thus, there is an onus on researchers and medical departments to develop a better understanding of the physical characteristics and demands, and the health and performance needs of female soccer players. In this review, we discuss the current research, as well as the knowledge gaps, of six major topics: physical demands, talent identification, body composition, injury risk and prevention, health and nutrition. Data on female talent identification are scarce, and future studies need to elucidate the influence of relative age and maturation selection across age groups. Regarding the physical demands, more research is needed on the pattern of high-intensity sprinting during matches and the contribution of soccer-specific movements. Injuries are not uncommon in female soccer players, but targeting intrinsically modifiable factors with injury prevention programmes can reduce injury rates. The anthropometric and physical characteristics of female players are heterogeneous and setting specific targets should be discouraged in youth and sub-elite players. Menstrual cycle phase may influence performance and injury risk; however, there are few studies in soccer players. Nutrition plays a critical role in health and performance and ensuring adequate energy intake remains a priority. Despite recent progress, there is considerably less research in female than male soccer players. Many gaps in our understanding of how best to develop and manage the health and performance of female soccer players remain.
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Affiliation(s)
- Rebecca K Randell
- Gatorade Sports Science Institute, Life Sciences R&D, PepsiCo, Leicester, UK.
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
| | - Thomas Clifford
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Barry Drust
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Samantha L Moss
- Gatorade Sports Science Institute, Life Sciences R&D, PepsiCo, Leicester, UK
- Department of Sport and Exercise Sciences, University of Chester, Chester, UK
| | - Viswanath B Unnithan
- Institute of Clinical Exercise and Health Science, Division of Sport and Exercise, School of Health and Life Sciences, University of the West of Scotland, Hamilton, Scotland, UK
| | | | - Naomi Datson
- Institute of Sport, University of Chichester, Chichester, UK
| | - Daniel Martin
- School of Sport and Exercise Science, University of Lincoln, Lincoln, UK
| | - Hannah Mayho
- Sports Science Department, Manchester City Football Club, Manchester, UK
| | - James M Carter
- Gatorade Sports Science Institute, Life Sciences R&D, PepsiCo, Leicester, UK
| | - Ian Rollo
- Gatorade Sports Science Institute, Life Sciences R&D, PepsiCo, Leicester, UK
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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8
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Surapongchai J, Saengsirisuwan V, Rollo I, Randell RK, Nithitsuttibuta K, Sainiyom P, Leow CHW, Lee JKW. Hydration Status, Fluid Intake, Sweat Rate, and Sweat Sodium Concentration in Recreational Tropical Native Runners. Nutrients 2021; 13:1374. [PMID: 33923890 PMCID: PMC8072971 DOI: 10.3390/nu13041374] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/01/2021] [Accepted: 04/15/2021] [Indexed: 01/12/2023] Open
Abstract
AIM The purpose of this study was to evaluate hydration status, fluid intake, sweat rate, and sweat sodium concentration in recreational tropical native runners. METHODS A total of 102 males and 64 females participated in this study. Participants ran at their self-selected pace for 30-100 min. Age, environmental conditions, running profiles, sweat rates, and sweat sodium data were recorded. Differences in age, running duration, distance and pace, and physiological changes between sexes were analysed. A p-value cut-off of 0.05 depicted statistical significance. RESULTS Males had lower relative fluid intake (6 ± 6 vs. 8 ± 7 mL·kg-1·h-1, p < 0.05) and greater relative fluid balance deficit (-13 ± 8 mL·kg-1·h-1 vs. -8 ± 7 mL·kg-1·h-1, p < 0.05) than females. Males had higher whole-body sweat rates (1.3 ± 0.5 L·h-1 vs. 0.9 ± 0.3 L·h-1, p < 0.05) than females. Mean rates of sweat sodium loss (54 ± 27 vs. 39 ± 22 mmol·h-1) were higher in males than females (p < 0.05). CONCLUSIONS The sweat profile and composition in tropical native runners are similar to reported values in the literature. The current fluid replacement guidelines pertaining to volume and electrolyte replacement are applicable to tropical native runners.
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Affiliation(s)
| | - Vitoon Saengsirisuwan
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (V.S.); (K.N.); (P.S.)
| | - Ian Rollo
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire LE4 1ET, UK; (I.R.); (R.K.R.)
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK
| | - Rebecca K. Randell
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire LE4 1ET, UK; (I.R.); (R.K.R.)
- School of Sport, Exercise and Health Sciences, Loughborough University, Leicestershire LE11 3TU, UK
| | - Kanpiraya Nithitsuttibuta
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (V.S.); (K.N.); (P.S.)
| | - Patarawadee Sainiyom
- Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (V.S.); (K.N.); (P.S.)
| | - Clarence Hong Wei Leow
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119283, Singapore; (C.H.W.L.); (J.K.W.L.)
| | - Jason Kai Wei Lee
- Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119283, Singapore; (C.H.W.L.); (J.K.W.L.)
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117593, Singapore
- N.1 Institute for Health, National University of Singapore, Singapore 117456, Singapore
- Global Asia Institute, National University of Singapore, Singapore 119076, Singapore
- Institute for Digital Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117456, Singapore
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore 117609, Singapore
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9
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Different Waters for Different Performances: Can We Imagine Sport-Related Natural Mineral Spring Waters? WATER 2021. [DOI: 10.3390/w13020166] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Preserving the hydration status means to balance daily fluids and salt losses with gains, where the losses depend on several physiological and environmental factors. Especially for athletes, these losses could be relevant and negatively influence the performance: therefore, their hydro-saline status must be preserved with personalized pre- and rehydration plans all along the performance period. Scientific literature in this field is mainly dedicated to artificial sport drinks. Different territories in most world areas are rich in drinking natural mineral spring waters with saline compositions that reflect their geological origin and that are used for human health (often under medical prescription). However, scarce scientific attention has been dedicated to the use of these waters for athletes. We therefore reviewed the existing literature from the innovative viewpoint of matching spring water mineral compositions with different athletic performances and their hydro-saline requirements.
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10
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Collins J, Maughan RJ, Gleeson M, Bilsborough J, Jeukendrup A, Morton JP, Phillips SM, Armstrong L, Burke LM, Close GL, Duffield R, Larson-Meyer E, Louis J, Medina D, Meyer F, Rollo I, Sundgot-Borgen J, Wall BT, Boullosa B, Dupont G, Lizarraga A, Res P, Bizzini M, Castagna C, Cowie CM, D'Hooghe M, Geyer H, Meyer T, Papadimitriou N, Vouillamoz M, McCall A. UEFA expert group statement on nutrition in elite football. Current evidence to inform practical recommendations and guide future research. Br J Sports Med 2020; 55:416. [PMID: 33097528 DOI: 10.1136/bjsports-2019-101961] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2020] [Indexed: 01/09/2023]
Abstract
Football is a global game which is constantly evolving, showing substantial increases in physical and technical demands. Nutrition plays a valuable integrated role in optimising performance of elite players during training and match-play, and maintaining their overall health throughout the season. An evidence-based approach to nutrition emphasising, a 'food first' philosophy (ie, food over supplements), is fundamental to ensure effective player support. This requires relevant scientific evidence to be applied according to the constraints of what is practical and feasible in the football setting. The science underpinning sports nutrition is evolving fast, and practitioners must be alert to new developments. In response to these developments, the Union of European Football Associations (UEFA) has gathered experts in applied sports nutrition research as well as practitioners working with elite football clubs and national associations/federations to issue an expert statement on a range of topics relevant to elite football nutrition: (1) match day nutrition, (2) training day nutrition, (3) body composition, (4) stressful environments and travel, (5) cultural diversity and dietary considerations, (6) dietary supplements, (7) rehabilitation, (8) referees and (9) junior high-level players. The expert group provide a narrative synthesis of the scientific background relating to these topics based on their knowledge and experience of the scientific research literature, as well as practical experience of applying knowledge within an elite sports setting. Our intention is to provide readers with content to help drive their own practical recommendations. In addition, to provide guidance to applied researchers where to focus future efforts.
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Affiliation(s)
- James Collins
- Intra Performance Group, London, UK.,Performance and Research Team, Arsenal Football Club, London, UK
| | | | - Michael Gleeson
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Johann Bilsborough
- Faculty of Health, University of Technology, Sydney, New South Wales, Australia.,New England Patriots, Foxboro, MA, USA
| | - Asker Jeukendrup
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK.,MySport Science, Birmingham, UK
| | - James P Morton
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - S M Phillips
- Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Lawrence Armstrong
- Human Performance Laboratory, University of Connecticut, Storrs, CT, USA
| | - Louise M Burke
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, VIC, Australia
| | - Graeme L Close
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Rob Duffield
- Faculty of Health, University of Technology, Sydney, New South Wales, Australia.,Medical Department, Football Federation Australia, Sydney, New South Wales, Australia
| | - Enette Larson-Meyer
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA, USA
| | - Julien Louis
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Daniel Medina
- Athlete Care and Performance, Monumental Sports & Entertainment, Washington, DC, USA
| | - Flavia Meyer
- Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Ian Rollo
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK.,PepsiCo Life Sciences, Global R&D, Gatorade Sports Science Institute, Birmingham, UK
| | | | - Benjamin T Wall
- Department of Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | | | - Gregory Dupont
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | | | - Peter Res
- Dutch Olympic Team, Amsterdam, Netherlands
| | - Mario Bizzini
- Research and Human Performance Lab, Schulthess Clinic, Zurich, Switzerland
| | - Carlo Castagna
- University of Rome Tor Vergata, Rome, Italy.,Technical Department, Italian Football Federation (FIGC), Florence, Italy.,Italian Football Referees Association, Bologna, Italy
| | - Charlotte M Cowie
- Technical Directorate, Football Association, Burton upon Trent, UK.,Medical Committee, UEFA, Nyon, Switzerland
| | - Michel D'Hooghe
- Medical Committee, UEFA, Nyon, Switzerland.,Medical Centre of Excelence, Schulthess Clinic, Zurich, Switzerland
| | - Hans Geyer
- Center for Preventive Doping Research, German Sport University Cologne, Cologne, Germany
| | - Tim Meyer
- Medical Committee, UEFA, Nyon, Switzerland.,Institute of Sports and Preventive Medicine, Saarland University, Saarbrücken, Germany
| | | | | | - Alan McCall
- Performance and Research Team, Arsenal Football Club, London, UK .,Medical Department, Football Federation Australia, Sydney, New South Wales, Australia.,Sport, Exercise and Health Sciences, School of Applied Sciences, Edinburgh Napier University, Edinburgh, UK
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11
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Effects of Field Position on Fluid Balance and Electrolyte Losses in Collegiate Women's Soccer Players. ACTA ACUST UNITED AC 2020; 56:medicina56100502. [PMID: 32987967 PMCID: PMC7601799 DOI: 10.3390/medicina56100502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/19/2020] [Accepted: 09/21/2020] [Indexed: 11/17/2022]
Abstract
Background and objectives: Research investigating hydration strategies specialized for women’s soccer players is limited, despite the growth in the sport. The purpose of this study was to determine the effects of fluid balance and electrolyte losses in collegiate women’s soccer players. Materials and Methods: Eighteen NCAA Division I women’s soccer players were recruited (age: 19.2 ± 1.0 yr; weight: 68.5 ± 9.0 kg, and height: 168.4 ± 6.7 cm; mean ± SD), including: 3 forwards (FW), 7 mid-fielders (MD), 5 defenders (DF), and 3 goalkeepers (GK). Players practiced outdoor during spring off-season training camp for a total 14 practices (WBGT: 18.3 ± 3.1 °C). The main outcome measures included body mass change (BMC), sweat rate, urine and sweat electrolyte concentrations, and fluid intake. Results: Results were analyzed for comparison between low (LOW; 16.2 ± 2.6° C, n = 7) and moderate risk environments for hyperthermia (MOD; 20.5 ± 1.5 °C, n = 7) as well as by field position. The majority (54%) of players were in a hypohydrated state prior to practice. Overall, 26.7% of players had a %BMC greater than 0%, 71.4% of players had a %BMC less than −2%, and 1.9% of players had a %BMC greater than −2% (all MD position). Mean %BMC and sweat rate in all environmental conditions were −0.4 ± 0.4 kg (−0.5 ± 0.6% body mass) and 1.03 ± 0.21 mg·cm−2·min−1, respectively. In the MOD environment, players exhibited a greater sweat rate (1.07 ± 0.22 mg·cm−2·min−1) compared to LOW (0.99 ± 0.22 mg·cm−2·min−1; p = 0.02). By position, DF had a greater total fluid intake and a lower %BMC compared to FW, MD, and GK (all p < 0.001). FW had a greater sweat sodium (Na+) (51.4 ± 9.8 mmol·L−1), whereas GK had the lowest sweat sodium (Na+) (30.9 ± 3.9 mmol·L−1). Conclusions: Hydration strategies should target pre-practice to ensure players are adequately hydrated. Environments deemed to be of moderate risk of hyperthermia significantly elevated the sweat rate but did not influence fluid intake and hydration status compared to low-risk environments. Given the differences in fluid balance and sweat responses, recommendations should be issued relative to soccer position.
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12
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Peloquin DM, Baumann EJ, Luxton TP. Multi-method assessment of PVP-coated silver nanoparticles and artificial sweat mixtures. CHEMOSPHERE 2020; 249:126173. [PMID: 32065993 PMCID: PMC7449241 DOI: 10.1016/j.chemosphere.2020.126173] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 02/04/2020] [Accepted: 02/09/2020] [Indexed: 05/19/2023]
Abstract
Research presented here utilizes silver nanoparticles (AgNPs) as a case study for how the immediate local environment alters the physical and chemical properties of nanomaterials. Dermal exposure is a primary route for exposure to many of the consumer products containing AgNPs. Interactions between AgNPs and human sweat/perspiration are critical for understanding how changes in Ag speciation will impact exposure. Previous studies have examined silver release from AgNP-containing products after exposure to artificial sweat (AS), however there is no basic assessment of how mixtures of AgNPs and AS alter the physical and chemical properties of AgNPs. The current research evaluated changes in size, aggregation, chemical composition, and silver speciation of four different sizes of AgNPs exposed to four different formulations of AS. The AS formulations were from standardized methods with different chemical compositions, ionic strengths, and pH. Samples were collected at four-time intervals for analysis using dynamic light scattering , UV-Vis spectroscopy, and single-particle inductively coupled plasma-mass spectrometry . Each mixture was also prepared for speciation analysis using X-ray absorption spectroscopy and scanning electron microscopy coupled to energy-dispersive X-ray analysis. The equivalent diameter measurements from the three techniques followed the order of DLS > UV-Vis > spICP-MS. Speciation analyses indicate significant changes for the smaller NPs, while the largest (100 nm) NPs had less measurable differences. This study shows the need to fully understand what specific information an analytical technique might provide and to use those techniques properly in tandem to give the fullest answer to a given research question.
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Affiliation(s)
- Derek M Peloquin
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Rd, Oak Ridge, TN, 37830, USA; U.S. Environmental Protection Agency, Office of Research and Development, 26 West Martin Luther King Dr, Cincinnati, OH, 45268, USA.
| | - Eric J Baumann
- Oak Ridge Institute for Science and Education, 1299 Bethel Valley Rd, Oak Ridge, TN, 37830, USA; Pegasus Technical Services, Inc., 46 East Hollister Street, Cincinnati, OH, 45219, USA.
| | - Todd P Luxton
- U.S. Environmental Protection Agency, Office of Research and Development, 26 West Martin Luther King Dr, Cincinnati, OH, 45268, USA.
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13
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Castro-Sepulveda M, Cancino J, Jannas-Vela S, Jesam F, Lobos C, Del Coso J, Zbinden-Foncea H. Role of Basal Hormones on Sweat Rate and Sweat Na+ Loss in Elite Women Soccer Players. Int J Sports Med 2020; 41:646-651. [PMID: 32455452 DOI: 10.1055/a-1165-2072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
We aimed to determine whether basal concentrations of testosterone, cortisol or the ratio testosterone/cortisol were related to sweat Na+ loss, sweat Na+ concentration ([Na+]) and sweat rate during exercise. Twenty-two female elite soccer players participated in the study. Testosterone and cortisol were measured in blood samples before exercise. Sweat samples were collected during a training session (~20°C, ~30% RH, and ~0.55 m/s of wind speed) to measure sweat [Na+]. Sweat rate was determined by considering the difference between post-and pre-body weight, along with the amount of liquid consumed. During exercise, sweat Na+ loss (0.33[0.19] g/h) and sweat rate (0.49[0.20] L/h) were related to basal testosterone concentration (1.4[0.4] pg/mL) (r=0.54; r=0.55, respectively; p<0.05), but not with basal cortisol concentration (119.2[24.2] ng/mL) nor testosterone/cortisol ratio (0.012[0.003]) (p>0.05). However, when Na+ loss was adjusted to sweat rate, no association was found between Na+ loss and testosterone (p>0.05). In addition, no differences were found between players with high vs. low Na+ loss adjusted to sweat loss in menstrual phase or intensity during exercise (p>0.05). In conclusion, these results suggest that in these specific environmental conditions, basal levels of testosterone might increase sweat rate and therefore, the amount of Na+ lost during exercise in elite women soccer players.
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Affiliation(s)
- Mauricio Castro-Sepulveda
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Jorge Cancino
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Sebastian Jannas-Vela
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Francisca Jesam
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Casandra Lobos
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Juan Del Coso
- Centre for Sport Studies, Rey Juan Carlos University, Fuenlabrada, Madrid, Spain
| | - Hermann Zbinden-Foncea
- Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile.,Centro de Salud Deportiva, Clinica Santa María, Santiago, Chile
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14
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Dobrowolski H, Karczemna A, Włodarek D. Nutrition for Female Soccer Players-Recommendations. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:E28. [PMID: 32284520 PMCID: PMC7022222 DOI: 10.3390/medicina56010028] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 12/11/2022]
Abstract
Soccer is one of the most popular sports in the world. As its number of players is increasing, the number of female players is also on the rise. However, there are limited data about how the diets of female soccer players should be designed. Thus, the aim of our work is to deliver concise nutritional recommendations for women practicing this sport. Based on a literature review, we emphasize that individual adjustment of the energy value of the diet is the key factor for the physical performance of female soccer players. Appropriate macronutrient intake makes it possible to achieve the proper energy value of the diet (5-10 g/kg body mass/day carbohydrates; 1.2-1.7 g/kg body mass/day proteins; <30% fats from energy). The micronutrients should be consumed in amounts corresponding to individual values recommended in national standards. Soccer players should pay special attention to the proper consumption of such micronutrients, as well as vitamins such as iron, calcium, and vitamin D. The right amount of fluid intake, consistent with the player's needs, is crucial in maximizing exercise performance. The diet of a female practicing soccer is usually characterized with low energy values, which increases the risk of various health consequences related to low energy availability. Monitoring the diets of female soccer players is, therefore, necessary.
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Affiliation(s)
- Hubert Dobrowolski
- Department of Dietetics, Institute of Human Nutrition Sciences, Warsaw University of Life Sciences (SGGW), 159c Nowoursynowska Str., 02-776 Warsaw, Poland; (A.K.)
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15
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Bigg JL, Gamble AS, Vermeulen TF, Bigg LM, Spriet LL. Sweat Loss and Fluid Intake of Female Varsity Ice Hockey Players During On-Ice Practices and Games. J Strength Cond Res 2019; 34:389-395. [DOI: 10.1519/jsc.0000000000003351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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16
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Chapelle L, Tassignon B, Rommers N, Mertens E, Mullie P, Clarys P. Pre-exercise hypohydration prevalence in soccer players: A quantitative systematic review. Eur J Sport Sci 2019; 20:744-755. [PMID: 31526234 DOI: 10.1080/17461391.2019.1669716] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Pre-exercise hypohydration can impair soccer performance and has been extensively studied in different soccer populations. Therefore, the aim of this systematic review was to report hypohydration prevalence, measured by blood or urine samples, in different soccer populations based on sex (males and females), performance level (professional and recreational players) and context (training sessions and games). The Pubmed, Web of Science and SPORTDiscus databases were systematically searched until November 2018. Data were pooled to compare hypohydration prevalence between the different subgroups. Following the systematic search selection process, 24 studies were included. The results indicated that overall pre-exercise hypohydration prevalence was 63.3%, 37.4% and 58.8% for urine specific gravity (USG), urine osmolality (U Osm) and urine colour, respectively. Furthermore, no study implemented blood samples to examine hypohydration prevalence in soccer players. The subgroup analyses using USG data indicated that pre-exercise hypohydration prevalence was significantly higher amongst males (66.0%; p = 0.001), professional soccer players (66.2%; p = 0.020) and before a training session (79.6%; p < 0.001). Pre-exercise hypohydration prevalence was 46.8% among female soccer players, 55.6% in recreational soccer players and 41,3% before a game. The subgroup analyses using U Osm data indicated that hypohydration prevalence was significantly higher before a training session (52.6%; p = 0.023). Based on these results, it can be concluded that hypohydration prevalence in soccer players is of major concern. Future research should explore how pre-exercise hydration status can be improved in a sustainable way.
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Affiliation(s)
- L Chapelle
- Faculty of Physical Education and Physiotherapy, Department of Movement and Sports Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - B Tassignon
- Faculty of Physical Education and Physiotherapy, Human Physiology and Sports Physiotherapy Research Group, Vrije Universiteit Brussel, Brussels, Belgium
| | - N Rommers
- Faculty of Physical Education and Physiotherapy, Department of Movement and Sports Sciences, Vrije Universiteit Brussel, Brussels, Belgium.,Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.,Research Foundation Flanders (FWO), Belgium
| | - E Mertens
- Faculty of Physical Education and Physiotherapy, Department of Movement and Sports Sciences, Vrije Universiteit Brussel, Brussels, Belgium.,Erasmus University College, Brussels, Belgium
| | - P Mullie
- Faculty of Physical Education and Physiotherapy, Department of Movement and Sports Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - P Clarys
- Faculty of Physical Education and Physiotherapy, Department of Movement and Sports Sciences, Vrije Universiteit Brussel, Brussels, Belgium
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17
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Barnes KA, Anderson ML, Stofan JR, Dalrymple KJ, Reimel AJ, Roberts TJ, Randell RK, Ungaro CT, Baker LB. Normative data for sweating rate, sweat sodium concentration, and sweat sodium loss in athletes: An update and analysis by sport. J Sports Sci 2019; 37:2356-2366. [DOI: 10.1080/02640414.2019.1633159] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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18
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Relf R, Willmott A, Flint MS, Beale L, Maxwell N. Reliability of a wearable sweat rate monitor and routine sweat analysis techniques under heat stress in females. J Therm Biol 2018; 79:209-217. [PMID: 30612681 DOI: 10.1016/j.jtherbio.2018.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 11/17/2022]
Abstract
INTRODUCTION The aim of the study was to evaluate the reliability of five different sweat analysis techniques which measure; whole body sweat rate [WBSR], local sweat rate [LSR] (via technical absorbent [TA] method and KuduSmart® monitor), sweat conductivity [SC] and sweat gland activation [SGA] in a female population when exercising moderately under heat stress. METHODS Fourteen females (age; 26 ± 7 years, body mass; 66.5 ± 7.6 kg, height; 167.1 ± 6.4 cm) completed a preliminary threshold walking test (to determine exercise intensity) and two main trials, separated by 2 days. Main trials consisted of 30-min seated rest in the environmental chamber (35 °C, 50% relative humidity) in an upper body sauna-suit, before its removal, and walking at a moderate intensity (4 metabolic equivalents) for 30-min (speeds ranged from 4.8 to 6.5 km h-1). WBSR was measured via nude mass pre and post exercise. The TA and Tegaderm patches (for sweat sodium chloride) were placed on the back, forearm and chest for the entire 60-min, replicated for all participants for both trials. SGA was assessed following the 60-min trial and the KuduSmart® monitor was placed on the left arm for the 30-min of exercise. RESULTS WBSR, LSR methods and SC demonstrated no difference between trials (p > 0.05), good agreement (within limits), strong correlations (r ≥ 0.88) and low typical error of measurements [TEM] (< 0.04 L min-1, 0.13 mg min-1 cm-2 and 8 mmol L-1, respectively). SGA method showed moderate intra-class correlation (r = 0.80), with high TEM (5 glands) and large limits of agreement. CONCLUSION Sudomotor function is reliable, as demonstrated by good reliability, small TEM and strong correlations. The use of these sweat techniques is appropriate and practical in females who are exercising at moderate intensity under heat stress, and so, may aid future interventions. SGA shows larger variation and should be used with caution.
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Affiliation(s)
- Rebecca Relf
- Environmental Extremes Laboratory, University of Brighton, Eastbourne BN20 7SR, UK.
| | - Ashley Willmott
- Environmental Extremes Laboratory, University of Brighton, Eastbourne BN20 7SR, UK
| | - Melanie S Flint
- Cancer Stress Laboratory, University of Brighton, Moulsecoomb BN24GJ, UK; Centre for Stress and Age-Related Disease, Brighton, East Sussex, UK
| | - Louisa Beale
- Environmental Extremes Laboratory, University of Brighton, Eastbourne BN20 7SR, UK
| | - Neil Maxwell
- Environmental Extremes Laboratory, University of Brighton, Eastbourne BN20 7SR, UK
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19
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Sweating Rate and Sweat Sodium Concentration in Athletes: A Review of Methodology and Intra/Interindividual Variability. Sports Med 2018; 47:111-128. [PMID: 28332116 PMCID: PMC5371639 DOI: 10.1007/s40279-017-0691-5] [Citation(s) in RCA: 182] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Athletes lose water and electrolytes as a consequence of thermoregulatory sweating during exercise and it is well known that the rate and composition of sweat loss can vary considerably within and among individuals. Many scientists and practitioners conduct sweat tests to determine sweat water and electrolyte losses of athletes during practice and competition. The information gleaned from sweat testing is often used to guide personalized fluid and electrolyte replacement recommendations for athletes; however, unstandardized methodological practices and challenging field conditions can produce inconsistent/inaccurate results. The primary objective of this paper is to provide a review of the literature regarding the effect of laboratory and field sweat-testing methodological variations on sweating rate (SR) and sweat composition (primarily sodium concentration [Na+]). The simplest and most accurate method to assess whole-body SR is via changes in body mass during exercise; however, potential confounding factors to consider are non-sweat sources of mass change and trapped sweat in clothing. In addition, variability in sweat [Na+] can result from differences in the type of collection system used (whole body or localized), the timing/duration of sweat collection, skin cleaning procedure, sample storage/handling, and analytical technique. Another aim of this paper is to briefly review factors that may impact intra/interindividual variability in SR and sweat [Na+] during exercise, including exercise intensity, environmental conditions, heat acclimation, aerobic capacity, body size/composition, wearing of protective equipment, sex, maturation, aging, diet, and/or hydration status. In summary, sweat testing can be a useful tool to estimate athletes’ SR and sweat Na+ loss to help guide fluid/electrolyte replacement strategies, provided that data are collected, analyzed, and interpreted appropriately.
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20
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Nuccio RP, Barnes KA, Carter JM, Baker LB. Fluid Balance in Team Sport Athletes and the Effect of Hypohydration on Cognitive, Technical, and Physical Performance. Sports Med 2017; 47:1951-1982. [PMID: 28508338 PMCID: PMC5603646 DOI: 10.1007/s40279-017-0738-7] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sweat losses in team sports can be significant due to repeated bursts of high-intensity activity, as well as the large body size of athletes, equipment and uniform requirements, and environmental heat stress often present during training and competition. In this paper we aimed to: (1) describe sweat losses and fluid balance changes reported in team sport athletes, (2) review the literature assessing the impact of hypohydration on cognitive, technical, and physical performance in sports-specific studies, (3) briefly review the potential mechanisms by which hypohydration may impact team sport performance, and (4) discuss considerations for future directions. Significant hypohydration (mean body mass loss (BML) >2%) has been reported most consistently in soccer. Although American Football, rugby, basketball, tennis, and ice hockey have reported high sweating rates, fluid balance disturbances have generally been mild (mean BML <2%), suggesting that drinking opportunities were sufficient for most athletes to offset significant fluid losses. The effect of hydration status on team sport performance has been studied mostly in soccer, basketball, cricket, and baseball, with mixed results. Hypohydration typically impaired performance at higher levels of BML (3-4%) and when the method of dehydration involved heat stress. Increased subjective ratings of fatigue and perceived exertion consistently accompanied hypohydration and could explain, in part, the performance impairments reported in some studies. More research is needed to develop valid, reliable, and sensitive sport-specific protocols and should be used in future studies to determine the effects of hypohydration and modifying factors (e.g., age, sex, athlete caliber) on team sport performance.
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Affiliation(s)
- Ryan P Nuccio
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA.
| | - Kelly A Barnes
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
| | - James M Carter
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
| | - Lindsay B Baker
- Gatorade Sports Science Institute, 617 W. Main St., Barrington, IL, 60010, USA
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21
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Turck D, Bresson JL, Burlingame B, Dean T, Fairweather-Tait S, Heinonen M, Hirsch-Ernst KI, Mangelsdorf I, McArdle H, Neuhäuser-Berthold M, Nowicka G, Pentieva K, Sanz Y, Siani A, Sjödin A, Stern M, Tomé D, Van Loveren H, Vinceti M, Willatts P, Aggett P, Martin A, Przyrembel H, Brönstrup A, Ciok J, Gómez Ruiz JÁ, de Sesmaisons-Lecarré A, Naska A. Dietary reference values for potassium. EFSA J 2016. [DOI: 10.2903/j.efsa.2016.4592] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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22
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Jones B, Till K, King R, Gray M, OʼHara J. Are Habitual Hydration Strategies of Female Rugby League Players Sufficient to Maintain Fluid Balance and Blood Sodium Concentration During Training and Match-Play? A Research Note From the Field. J Strength Cond Res 2016; 30:875-80. [PMID: 26332779 DOI: 10.1519/jsc.0000000000001158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Limited data exist on the hydration status of female athletes, with no data available on female rugby players. The objective of this study was to investigate the habitual hydration status on arrival, sweat loss, fluid intake, sweat Na loss, and blood [Na+] during field training and match-play in 10 international female rugby league players. Urine osmolality on arrival to match-play (382 ± 302 mOsmol·kg(-1)) and training (667 ± 260 mOsmol·kg(-1)) was indicative of euhydration. Players experienced a body mass loss of 0.50 ± 0.45 and 0.56 ± 0.53% during match-play and training, respectively. During match-play, players consumed 1.21 ± 0.43 kg of fluid and had a sweat loss of 1.54 ± 0.48 kg. During training, players consumed 1.07 ± 0.90 kg of fluid, in comparison with 1.25 ± 0.83 kg of sweat loss. Blood [Na+] was well regulated (Δ-0.7 ± 3.4 and Δ-0.4 ± 2.6 mmol·L(-1)), despite sweat [Na+] of 47.8 ± 5.7 and 47.2 ± 6.3 mmol·L(-1) during match-play and training. The findings of this study show mean blood [Na+] that seems to be well regulated despite losses of Na in sweat and electrolyte-free fluid consumption. For the duration of the study, players did not experience a body mass loss (dehydration >2%) indicative of a reduction in exercise performance, thus habitual hydration strategies seem adequate. Practitioners should evaluate the habitual hydration status of athletes to determine whether interventions above habitual strategies are warranted.
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Affiliation(s)
- Ben Jones
- Research Institute Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, West Yorkshire, United Kingdom
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23
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Castro-Sepulveda M, Astudillo J, Letelier P, Zbinden-Foncea H. Prevalence of Dehydration Before Training Sessions, Friendly and Official Matches in Elite Female Soccer Players. J Hum Kinet 2016; 50:79-84. [PMID: 28149344 PMCID: PMC5260643 DOI: 10.1515/hukin-2015-0145] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2016] [Indexed: 11/29/2022] Open
Abstract
This study aimed to evaluate and compare the hydration states prior to different sporting events (training sessions, friendly and official matches) in elite female soccer players and relate that to the importance that the player attached to the hydration state as a determinant of sports performance. The hydration state of 17 female elite soccer players (age: 21.5 ± 3 years; body mass: 62 ± 6 kg; body height: 165 ± 9 cm) was determined by measuring their urine specific gravity (USG) prior to three different sports events: training sessions (PT), friendly (PF) and official (PO) matches. The importance that each player attached to the hydration state as a determinant of sports performance was evaluated through a simple questionnaire. An average of 47.05% of the soccer players were severely dehydrated (USG > 1.030), 33.33% were significantly dehydrated (USG > 1.020), 17.64% were mildly dehydrated (USG > 1.010) and 1.96% were euhydrated (USG < 1.010). The average USG was 1.027 ± 0.007 (PT = 1.029 ± 0.009; PF = 1.023 ± 0.010 and PO = 1.030 ± 0.006). Differences were found between urine specific gravity prior to a friendly and an official match (p = 0.03). No relationship was found between urine specific gravity and the importance each player attached to the hydration state as a determinant of sports performance. The results show that dehydration is the most prevalent hydration state of elite soccer players before training sessions, friendly and official matches. Players were most dehydrated prior to official matches, which was unlinked to the players’ perceived importance of hydration for sports performance.
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Affiliation(s)
| | - Javier Astudillo
- Exercise Science Laboratory, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Pablo Letelier
- Exercise Science Laboratory, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Hermann Zbinden-Foncea
- Exercise Science Laboratory, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
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24
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Baker LB, Barnes KA, Anderson ML, Passe DH, Stofan JR. Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes. J Sports Sci 2015; 34:358-68. [DOI: 10.1080/02640414.2015.1055291] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Cogswell ME, Maalouf J, Elliott P, Loria CM, Patel S, Bowman BA. Use of Urine Biomarkers to Assess Sodium Intake: Challenges and Opportunities. Annu Rev Nutr 2015; 35:349-87. [PMID: 25974702 PMCID: PMC5497310 DOI: 10.1146/annurev-nutr-071714-034322] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This article summarizes current data and approaches to assess sodium intake in individuals and populations. A review of the literature on sodium excretion and intake estimation supports the continued use of 24-h urine collections for assessing population and individual sodium intake. Since 2000, 29 studies used urine biomarkers to estimate population sodium intake, primarily among adults. More than half used 24-h urine; the rest used a spot/casual, overnight, or 12-h specimen. Associations between individual sodium intake and health outcomes were investigated in 13 prospective cohort studies published since 2000. Only three included an indicator of long-term individual sodium intake, i.e., multiple 24-h urine specimens collected several days apart. Although not insurmountable, logistic challenges of 24-h urine collection remain a barrier for research on the relationship of sodium intake and chronic disease. Newer approaches, including modeling based on shorter collections, offer promise for estimating population sodium intake in some groups.
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Affiliation(s)
- Mary E Cogswell
- Division for Heart Disease and Stroke Prevention, Centers for Disease Control and Prevention, Atlanta, Georgia 30341; , ,
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Baker LB, Ungaro CT, Barnes KA, Nuccio RP, Reimel AJ, Stofan JR. Validity and reliability of a field technique for sweat Na+ and K+ analysis during exercise in a hot-humid environment. Physiol Rep 2014; 2:e12007. [PMID: 24793982 PMCID: PMC4098735 DOI: 10.14814/phy2.12007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
This study compared a field versus reference laboratory technique for extracting (syringe vs. centrifuge) and analyzing sweat [Na+] and [K+] (compact Horiba B‐722 and B‐731, HORIBA vs. ion chromatography, HPLC) collected with regional absorbent patches during exercise in a hot‐humid environment. Sweat samples were collected from seven anatomical sites on 30 athletes during 1‐h cycling in a heat chamber (33°C, 67% rh). Ten minutes into exercise, skin was cleaned/dried and two sweat patches were applied per anatomical site. After removal, one patch per site was centrifuged and sweat was analyzed with HORIBA in the heat chamber (CENTRIFUGE HORIBA) versus HPLC (CENTRIFUGE HPLC). Sweat from the second patch per site was extracted using a 5‐mL syringe and analyzed with HORIBA in the heat chamber (SYRINGE HORIBA) versus HPLC (SYRINGE HPLC). CENTRIFUGE HORIBA, SYRINGE HPLC, and SYRINGE HORIBA were highly related to CENTRIFUGE HPLC ([Na+]: ICC = 0.96, 0.94, and 0.93, respectively; [K+]: ICC = 0.87, 0.92, and 0.84, respectively), while mean differences from CENTRIFUGE HPLC were small but usually significant ([Na+]: 4.7 ± 7.9 mEql/L, −2.5 ± 9.3 mEq/L, 4.0 ± 10.9 mEq/L (all P < 0.001), respectively; [K+]: 0.44 ± 0.52 mEq/L (P < 0.001), 0.01 ± 0.49 mEq/L (P = 0.77), 0.50 ± 0.48 mEq/L (P < 0.001), respectively). On the basis of typical error of the measurement results, sweat [Na+] and [K+] obtained with SYRINGE HORIBA falls within ±15.4 mEq/L and ±0.68 mEq/L, respectively, of CENTRIFUGE HPLC 95% of the time. The field (SYRINGE HORIBA) method of extracting and analyzing sweat from regional absorbent patches may be useful in obtaining sweat [Na+] when rapid estimates in a hot‐humid field setting are needed. This study compared a field versus reference laboratory technique for extracting (SYRINGE vs. CENTRIFUGE) and analyzing sweat [Na+] and [K+] (compact HORIBA B‐722 and B‐731 versus ion chromatography, HPLC) collected with regional absorbent patches during exercise in a hot‐humid environment. The HORIBA analyzers provided highly reliable test‐retest and day‐to‐day measurements of sweat [Na+] and [K+]. The 95% limit of agreement between the SYRINGE HORIBA field technique and the reference laboratory‐based CENTRIFUGE HPLC technique was ±15.4 mEq/L and ±0.68 mEq/L for [Na+] and [K+], respectively; which may be acceptable in a field‐testing context, when simply aiming to estimate electrolyte losses for the purpose of identifying athletes/workers at greater risk for large electrolyte losses.
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Affiliation(s)
- Lindsay B Baker
- Gatorade Sports Science Institute, Barrington, Illinois, USA
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Variability of measurements of sweat sodium using the regional absorbent-patch method. Int J Sports Physiol Perform 2014; 9:832-8. [PMID: 24436351 DOI: 10.1123/ijspp.2013-0480] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
CONTEXT There is interest in including recommendations for the replacement of the sodium lost in sweat in individualized hydration plans for athletes. PURPOSE Although the regional absorbent-patch method provides a practical approach to measuring sweat sodium losses in field conditions, there is a need to understand the variability of estimates associated with this technique. METHODS Sweat samples were collected from the forearms, chest, scapula, and thigh of 12 cyclists during 2 standardized cycling time trials in the heat and 2 in temperate conditions. Single measure analysis of sodium concentration was conducted immediately by ion-selective electrodes (ISE). A subset of 30 samples was frozen for reanalysis of sodium concentration using ISE, flame photometry (FP), and conductivity (SC). RESULTS Sweat samples collected in hot conditions produced higher sweat sodium concentrations than those from the temperate environment (P = .0032). A significant difference (P = .0048) in estimates of sweat sodium concentration was evident when calculated from the forearm average (mean ± 95% CL; 64 ± 12 mmol/L) compared with using a 4-site equation (70 ± 12 mmol/L). There was a high correlation between the values produced using different analytical techniques (r2 = .95), but mean values were different between treatments (frozen FP, frozen SC > immediate ISE > frozen ISE; P < .0001). CONCLUSION Whole-body sweat sodium concentration estimates differed depending on the number of sites included in the calculation. Environmental testing conditions should be considered in the interpretation of results. The impact of sample freezing and subsequent analytical technique was small but statistically significant. Nevertheless, when undertaken using a standardized protocol, the regional absorbent-patch method appears to be a relatively robust field test.
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Gibson JC, Stuart-Hill LA, Pethick W, Gaul CA. Hydration status and fluid and sodium balance in elite Canadian junior women's soccer players in a cool environment. Appl Physiol Nutr Metab 2012; 37:931-7. [PMID: 22803782 DOI: 10.1139/h2012-073] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dehydration can impair mental and on-field performance in soccer athletes; however, there is little data available from the female adolescent player. There is a lack of research investigating fluid and electrolyte losses in cool temperatures. Therefore, the purpose of this study was to investigate the pretraining hydration status, fluid balance, and sweat sodium loss in 34 female Canadian junior elite soccer athletes (mean age ± SD, 15.7 ± 0.7 years) in a cool environment. Data were collected during two 90 min on-field training sessions (9.8 ± 3.3 °C, 63% ± 12% relative humidity). Prepractice urine specific gravity (USG), sweat loss (pre- and post-training body mass), and sweat sodium concentration (regional sweat patch method) were measured at each session. Paired t tests were used to identify significant differences between training sessions and Pearson's product moment correlation analysis was used to assess any relationships between selected variables (p ≤ 0.05). We found that 45% of players presented to practice in a hypohydrated state (USG > 1.020). Mean percent body mass loss was 0.84% ± 0.07% and sweat loss was 0.69 ± 0.54 L. Although available during each training session, fluid intake was low (63.6% of players consumed <250 mL). Mean sweat sodium concentration was 48 ± 12 mmol·L⁻¹. Despite low sweat and moderate sodium losses, players did not drink enough to avoid mild fluid and sodium deficits during training. The findings from this study highlights the individual variations that occur in hydration management in athletes and thus the need for personalized hydration guidelines.
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Affiliation(s)
- Jennifer C Gibson
- School of Exercise Science, Physical and Health Education, University of Victoria, Victoria, BC, Canada.
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Duffield R, McCall A, Coutts AJ, Peiffer JJ. Hydration, sweat and thermoregulatory responses to professional football training in the heat. J Sports Sci 2012; 30:957-65. [DOI: 10.1080/02640414.2012.689432] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Ely MR, Kenefick RW, Cheuvront SN, Chinevere TD, Lacher CP, Lukaski HC, Montain SJ. Surface contamination artificially elevates initial sweat mineral concentrations. J Appl Physiol (1985) 2011; 110:1534-40. [PMID: 21512152 DOI: 10.1152/japplphysiol.01437.2010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Several sweat mineral element concentrations decline with serial sampling. Possible causes include reduced dermal mineral concentrations or flushing of surface contamination. The purpose of this study was to simultaneously sample mineral concentrations in transdermal fluid (TDF), sweat, and serum during extended exercise-heat stress to determine if these compartments show the same serial changes during repeat sampling. Sixteen heat-acclimated individuals walked on a treadmill (1.56 m/s, 3.0% grade) in a 35°C, 20% relative humidity (RH), 1 m/s wind environment 50 min each hour for 3 h. Mineral concentrations of Ca, Cu, Fe, K, Mg, Na, and Zn were measured each hour from serum, sweat from upper back (sweat pouch) and arm (bag), and TDF from the upper back. Sites were meticulously cleaned to minimize surface contamination. Mineral concentrations were determined by spectrometry. TDF remained stable over time, with exception of a modest increase in TDF [Fe] (15%) and decrease in TDF [Zn] (-18%). Likewise, serum and pouch sweat samples were stable over time. In contrast, the initial arm bag sweat mineral concentrations were greater than those in the sweat pouch, and [Ca], [Cu], [Mg], and [Zn] declined 26-76% from initial to the subsequent samples, becoming similar to sweat pouch. Nominal TDF mineral shifts do not affect sweat mineral concentrations. Arm bag sweat mineral concentrations are initially elevated due to skin surface contaminants that are not removed despite meticulous cleaning (e.g., under fingernails, on arm hair), then decrease with extended sweating and approach those measured from the scapular region.
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Affiliation(s)
- Matthew R Ely
- U.S. Army Research Institute of Environmental Medicine, Kansas St., Bldg. 42, Natick, MA 01760-5007, USA.
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Baker LB, Stofan JR, Hamilton AA, Horswill CA. Comparison of regional patch collection vs. whole body washdown for measuring sweat sodium and potassium loss during exercise. J Appl Physiol (1985) 2009; 107:887-95. [PMID: 19541738 DOI: 10.1152/japplphysiol.00197.2009] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study compared simultaneous whole body washdown (WBW) and regional skin surface (REG) sweat collections to generate regression equations to predict WBW sweat Na(+) concentration ([Na(+)]) and K(+) concentration ([K(+)]) from single- and five-site REG sweat patch collections. Athletes (10 men, 10 women) cycled in a plastic chamber for 90 min in the heat. Before exercise, the subject and bike were washed with deionized water. After the onset of sweating, sterile patches were attached to the forearm, back, chest, forehead, and thigh and removed on saturation. After exercise, the subject and bike were washed with ammonium sulfate solution to collect all sweat electrolyte loss and determine the volume of unevaporated sweat. All individual patch sites and five-site REG (weighted for local sweat rate and body surface area) were significantly (P = 0.000) correlated with WBW sweat [Na(+)]. The equation for predicting WBW sweat [Na(+)] from five-site REG was y = 0.68x + 0.44 [r = 0.97, intraclass correlation coefficient (ICC) = 0.70] and did not differ between sexes. There were sex differences in the regression results between five-site REG and WBW sweat [K(+)] (men: y = 0.74x + 0.30, r = 0.89, ICC = 0.73; women: y = 0.04x + 3.18, r = 0.03, ICC = 0.00). Five-site REG sweat [Na(+)] and [K(+)] significantly overestimated that of WBW sweat (59 +/- 27 vs. 41 +/- 19 meq/l, P = 0.000 and 4.4 +/- 0.7 vs. 3.6 +/- 0.7 meq/l, P = 0.000, respectively). For both sexes, the best sites for predicting WBW sweat [Na(+)] and [K(+)] were the thigh (1 +/- 8 meq/l < WBW, P = 1.000, y = 0.75x + 11.37, r = 0.96, ICC = 0.93) and chest (0.2 +/- 0.3 meq/l > WBW, P = 1.000, y = 0.76x + 0.55, r = 0.89, ICC = 0.87), respectively. In conclusion, regression equations can be used to accurately and reliably predict WBW sweat [Na(+)] and [K(+)] from REG sweat collections when study conditions and techniques are similar to that of the present protocol.
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Affiliation(s)
- Lindsay B Baker
- Gatorade Sports Science Institute, Gatorade Research and Developement, Barrington, Illinois 60010, USA.
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