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Eifling KP, Gaudio FG, Dumke C, Lipman GS, Otten EM, Martin AD, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update. Wilderness Environ Med 2024; 35:112S-127S. [PMID: 38425235 DOI: 10.1177/10806032241227924] [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] [Indexed: 03/02/2024]
Abstract
The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.
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Affiliation(s)
- Kurt P Eifling
- Department of Emergency Medicine, University of Arkansas for Medical Sciences, Fayetteville, AR
| | - Flavio G Gaudio
- Department of Emergency Medicine, New York-Presbyterian Hospital / Weill Cornell Medical College, New York, NY
| | - Charles Dumke
- School of Integrative Physiology and Athletic Training, University of Montana, Missoula, MT
| | | | - Edward M Otten
- Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH
| | - August D Martin
- Department of Internal Medicine, University of Arkansas for Medical Sciences, Fayetteville, AR
| | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT
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AlJohani RA, Marzook NT. Knowledge, Attitudes, and Practices of Military Personnel Regarding Heat-Related Illness. Cureus 2023; 15:e49821. [PMID: 38164297 PMCID: PMC10758236 DOI: 10.7759/cureus.49821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2023] [Indexed: 01/03/2024] Open
Abstract
INTRODUCTION Heat-related illnesses are a global concern, affecting millions of people and leading to numerous deaths annually. Since military personnel are exposed to heat, the purpose of the study was to evaluate military personnel's knowledge, attitudes, and practices (KAP) related to heat-related illnesses. Their KAP may help to prevent heat-related illness. Methods: We conducted a cross-sectional study using a structured online questionnaire on 168 military personnel who were training and working in a high-temperature and high-humidity environment all year round in Jeddah, Saudi Arabia. The questionnaire assessed the KAP and associated factors and was distributed as a Google Form. RESULTS The mean knowledge score was 9.04 (range = 2-13, SD = 1.832), the mean awareness score was 9.61 (range = 4-15, SD = 2.415), and the mean practice score was 3.39 (range = 0-6, SD = 1.703). Most participants correctly identified symptoms (n=130; 77.4%). In terms of attitudes, most participants showed a good attitude (n=151; 81%), though 24.4% did not perceive the risk. Regarding practice, most were attentive to heat-related illness signs and hydration(75.6%), but there were gaps in receiving briefings from doctors (69%) and adequate guidance on treatment (56%). There was a split opinion on whether commanders adjust field activities based on temperature warnings (54.8% Yes, 45.2% No). There were no significant differences in knowledge scores based on age or educational level (both p>0.05), while some age and education-related differences were noted in practice scores (p<0.05). There was a positive correlation between knowledge and attitudes (r = 0.222, p = 0.004), knowledge and practices (r = 0.165, p = 0.033), and attitudes and practice (r=0.326, p < 0.001). CONCLUSION Our study found that military personnel generally possess good knowledge of heat-related illnesses and good attitudes and practices concerning heat-related illnesses. However, there are areas in need of improvement, and enhancing awareness and practical implementation of preventive measures, along with the development of precise guidance and protocols, should involve active collaboration between military commanders and healthcare professionals.
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Affiliation(s)
- Razan A AlJohani
- Emergency Department, King Fahad Armed Forces Hospital, Jeddah, SAU
| | - Naif T Marzook
- Emergency Department, King Fahad Armed Forces Hospital, Jeddah, SAU
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Knipping K, Kartaram SW, Teunis M, Zuithoff NPA, Buurman N, M’Rabet L, van Norren K, Witkamp R, Pieters R, Garssen J. Salivary concentrations of secretory leukocyte protease inhibitor and matrix metallopeptidase-9 following a single bout of exercise are associated with intensity and hydration status. PLoS One 2023; 18:e0291297. [PMID: 37992002 PMCID: PMC10664895 DOI: 10.1371/journal.pone.0291297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/25/2023] [Indexed: 11/24/2023] Open
Abstract
AIM To investigate the effects of exercise on salivary concentrations of inflammatory markers by analyzing a panel of 25 inflammatory markers in subjects who had participated in bicycle ergometer tests varying in workload and hydration status. METHODS Fifteen healthy young men (20-35 years) had performed 4 different exercise protocols of 1 hour duration in a randomly assigned cross-over design, preceded by a rest protocol. Individual workloads depended on participant's pre-assessed individual maximum workload (Wmax): rest (protocol 1), 70% Wmax in hydrated (protocol 2) and dehydrated (protocol 3) state, 50% Wmax (protocol 4) and intermittent 85%/55% Wmax in 2 min blocks (protocol 5). Saliva samples were collected before (T0) and immediately after exercise (T1), and at several time points after exercise (2 hours (T3), 3 hours (T4), 6 hours (T5) and 24 hours (T6)). Secretory Leukocyte Protease Inhibitor (SLPI), Matrix Metallopeptidase-9 (MMP-9) and lactoferrin was analyzed using a commercial ELISA kit, a panel of 22 cytokines and chemokines were analyzed using a commercial multiplex immunoassay. Data was analyzed using a multilevel mixed linear model, with multiple test correction. RESULTS Among a panel of 25 inflammatory markers, SLPI concentrations were significantly elevated immediately after exercise in all protocols compared to rest and higher concentrations reflected the intensity of exercise and hydration status. MMP-9 showed a significant increase in the 70% Wmax dehydrated, 50% Wmax and intermittent protocols. CONCLUSIONS Salivary concentrations of SLPI and MMP-9 seem associated with exercise intensity and hydration status and may offer non-invasive biomarkers to study (local) inflammatory responses to different exercise intensities in human studies.
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Affiliation(s)
- Karen Knipping
- Danone Nutricia Research, Utrecht, The Netherlands
- Department of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Shirley W. Kartaram
- Research Group Innovative Testing in Life Sciences and Chemistry, University of Applied Sciences Utrecht, Utrecht, The Netherlands
| | - Marc Teunis
- Research Group Innovative Testing in Life Sciences and Chemistry, University of Applied Sciences Utrecht, Utrecht, The Netherlands
| | - Nicolaas P. A. Zuithoff
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | | | - Laura M’Rabet
- Research Group Innovative Testing in Life Sciences and Chemistry, University of Applied Sciences Utrecht, Utrecht, The Netherlands
| | - Klaske van Norren
- Nutritional Biology, Division Human Nutrition and Health, Wageningen University & Research, Wageningen, The Netherlands
| | - Renger Witkamp
- Nutritional Biology, Division Human Nutrition and Health, Wageningen University & Research, Wageningen, The Netherlands
| | - Raymond Pieters
- Research Group Innovative Testing in Life Sciences and Chemistry, University of Applied Sciences Utrecht, Utrecht, The Netherlands
- Institute for Risk Assessment Sciences, Immunotoxicology (IRAS), Utrecht University, Utrecht, The Netherlands
| | - Johan Garssen
- Danone Nutricia Research, Utrecht, The Netherlands
- Department of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
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Jardine WT, Aisbett B, Kelly MK, Burke LM, Ross ML, Condo D, Périard JD, Carr AJ. The Effect of Pre-Exercise Hyperhydration on Exercise Performance, Physiological Outcomes and Gastrointestinal Symptoms: A Systematic Review. Sports Med 2023; 53:2111-2134. [PMID: 37490269 PMCID: PMC10587316 DOI: 10.1007/s40279-023-01885-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2023] [Indexed: 07/26/2023]
Abstract
BACKGROUND Fluid loss during prolonged exercise in hot conditions poses thermoregulatory and cardiovascular challenges for athletes that can lead to impaired performance. Pre-exercise hyperhydration using nutritional aids is a strategy that may prevent or delay the adverse effects of dehydration and attenuate the impact of heat stress on exercise performance. OBJECTIVES The aim of this systematic review was to examine the current literature to determine the effect of pre-exercise hyperhydration on performance, key physiological responses and gastrointestinal symptoms. METHODS English language, full-text articles that compared the intervention with a baseline or placebo condition were included. An electronic search of Medline Complete, SPORTDiscus and Embase were used to identify articles with the final search conducted on 11 October 2022. Studies were assessed using the American Dietetic Association Quality Criteria Checklist. RESULTS Thirty-eight studies involving 403 participants (n = 361 males) were included in this review (n = 22 assessed exercise performance or capacity). Two studies reported an improvement in time-trial performance (range 5.7-11.4%), three studies reported an improvement in total work completed (kJ) (range 4-5%) and five studies reported an increase in exercise capacity (range 14.3-26.2%). During constant work rate exercise, nine studies observed a reduced mean heart rate (range 3-11 beats min-1), and eight studies reported a reduced mean core temperature (range 0.1-0.8 °C). Ten studies reported an increase in plasma volume (range 3.5-12.6%) compared with a control. Gastrointestinal symptoms were reported in 26 studies, with differences in severity potentially associated with factors within the ingestion protocol of each study (e.g. treatment, dose, ingestion rate). CONCLUSIONS Pre-exercise hyperhydration may improve exercise capacity during constant work rate exercise due to a reduced heart rate and core temperature, stemming from an acute increase in plasma volume. The combination of different osmotic aids (e.g. glycerol and sodium) may enhance fluid retention and this area should continue to be explored. Future research should utilise valid and reliable methods of assessing gastrointestinal symptoms. Furthermore, studies should investigate the effect of hyperhydration on different exercise modalities whilst implementing a strong level of blinding. Finally, females are vastly underrepresented, and this remains a key area of interest in this area.
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Affiliation(s)
- William T Jardine
- School of Exercise and Nutrition Sciences, Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia.
| | - Brad Aisbett
- School of Exercise and Nutrition Sciences, Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Monica K Kelly
- School of Exercise and Nutrition Sciences, Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Louise M Burke
- Mary MacKillop Institute for Health Research, Exercise and Nutrition Research Program, Australian Catholic University, Watson, ACT, 2602, Australia
| | - Megan L Ross
- Mary MacKillop Institute for Health Research, Exercise and Nutrition Research Program, Australian Catholic University, Watson, ACT, 2602, Australia
| | - Dominique Condo
- School of Exercise and Nutrition Sciences, Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Bruce, ACT, 2617, Australia
| | - Amelia J Carr
- School of Exercise and Nutrition Sciences, Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
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Martins Januário W, Prata ERBDA, Natali AJ, Prímola-Gomes TN. Normal gastrointestinal temperature values measured through ingestible capsules technology: a systematic review. J Med Eng Technol 2023; 47:389-395. [PMID: 38780358 DOI: 10.1080/03091902.2024.2354793] [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: 10/20/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024]
Abstract
Climate change has amplified the importance of continuous and precise body core temperature (Tcore) monitoring in the everyday life. In this context, assessing Tcore through ingestible capsules technology, i.e., gastrointestinal temperature (Tgastrointestinal), emerges as a good alternative to prevent heat-related illness. Therefore, we conducted a systematic review to point out values of normal Tgastrointestinal measured through ingestible capsules in healthy humans. The study followed PRISMA guidelines and searched the PubMed and Scielo databases from 1971 to 2023. Our search strategy included the descriptors ("gastrointestinal temperature") AND ("measurement"), and eligible studies had to be written in English and measured Tgastrointestinal using ingestible capsules or sensors in healthy adults aged 18-59 at rest. Two pairs of researchers independently reviewed titles and abstracts and identified 35 relevant articles out of 1,088 in the initial search. An average value of 37.13 °C with a standard deviation of 0.24 °C was observed, independently of the gender. The values measured ranged from 36.70 °C to 37.69 °C. In conclusion, this systematic review pointed out the mean value of 37.13 ± 0.24 °C measured by ingestible capsules as reference for resting Tgastrointestinal in healthy adult individuals.
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Affiliation(s)
- William Martins Januário
- Departamento de Educação Física, Laboratório de Performance Humana, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
| | | | - Antônio José Natali
- Departamento de Educação Física, Laboratório de Biologia do Exercício, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
| | - Thales Nicolau Prímola-Gomes
- Departamento de Educação Física, Laboratório de Performance Humana, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
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Porto AA, Benjamim CJR, da Silva Sobrinho AC, Gomes RL, Gonzaga LA, da Silva Rodrigues G, Vanderlei LCM, Garner DM, Valenti VE. Influence of Fluid Ingestion on Heart Rate, Cardiac Autonomic Modulation and Blood Pressure in Response to Physical Exercise: A Systematic Review with Meta-Analysis and Meta-Regression. Nutrients 2023; 15:4534. [PMID: 37960187 PMCID: PMC10650885 DOI: 10.3390/nu15214534] [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: 05/27/2023] [Revised: 07/11/2023] [Accepted: 07/16/2023] [Indexed: 11/15/2023] Open
Abstract
A systematic review was undertaken to investigate the involvement of hydration in heart rate (HR), HR variability (HRV) and diastolic (DBP) and systolic (SBP) blood pressure in response to exercise. Data synthesis: The EMBASE, MEDLINE, Cochrane Library, CINAHL, LILACS and Web of Science databases were searched. In total, 977 studies were recognized, but only 36 were included after final screening (33 studies in meta-analysis). This study includes randomized controlled trials (RCTs) and non-RCTs with subjects > 18 years old. The hydration group consumed water or isotonic drinks, while the control group did not ingest liquids. For the hydration protocol (before, during and after exercise), the HR values during the exercise were lower compared to the controls (-6.20 bpm, 95%CI: -8.69; -3.71). In the subgroup analysis, "water ingested before and during exercise" showed lower increases in HR during exercise (-6.20, 95%CI: 11.70 to -0.71), as did "water was ingested only during exercise" (-6.12, 95%CI: -9.35 to -2.89). Water intake during exercise only revealed a trend of avoiding greater increases in HR during exercise (-4,60, 95%CI: -9.41 to 0.22), although these values were not significantly different (p = 0.06) from those of the control. "Isotonic intake during exercise" showed lower HRs than the control (-7.23 bpm, 95% CI: -11.68 to -2.79). The HRV values following the exercise were higher in the hydration protocol (SMD = 0.48, 95%CI: 0.30 to 0.67). The values of the SBP were higher than those of the controls (2.25 mmHg, 95%CI: 0.08 to 4.42). Conclusions: Hydration-attenuated exercise-induced increases in HR during exercise, improved autonomic recovery via the acceleration of cardiac vagal modulation in response to exercise and caused a modest increase in SBP values, but did not exert effects on DBP following exercise.
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Affiliation(s)
- Andrey A. Porto
- Department of Movement Sciences, São Paulo State University, UNESP, Presidente Prudente 19060-900, SP, Brazil; (L.A.G.); (V.E.V.)
| | - Cicero Jonas R. Benjamim
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (C.J.R.B.); (A.C.d.S.S.); (G.d.S.R.)
| | - Andressa Crystine da Silva Sobrinho
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (C.J.R.B.); (A.C.d.S.S.); (G.d.S.R.)
| | - Rayana Loch Gomes
- Department of Nutrition, Faculty of Health Sciences, Federal University of Grande Dourados, Dourados 79804-970, MS, Brazil;
| | - Luana A. Gonzaga
- Department of Movement Sciences, São Paulo State University, UNESP, Presidente Prudente 19060-900, SP, Brazil; (L.A.G.); (V.E.V.)
| | - Guilherme da Silva Rodrigues
- Department of Internal Medicine, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, SP, Brazil; (C.J.R.B.); (A.C.d.S.S.); (G.d.S.R.)
| | | | - David M. Garner
- Cardiorespiratory Research Group, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK;
| | - Vitor E. Valenti
- Department of Movement Sciences, São Paulo State University, UNESP, Presidente Prudente 19060-900, SP, Brazil; (L.A.G.); (V.E.V.)
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Ferguson DP, Alex PR, Castrucci JM, Akouri AM, Januszewski GR, Danes JD, Houck FL. Prompted hands-free drinking improves simulated race car driving in a hot environment. J Sports Sci 2023; 41:1093-1106. [PMID: 37728081 DOI: 10.1080/02640414.2023.2259213] [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: 06/06/2022] [Accepted: 08/10/2023] [Indexed: 09/21/2023]
Abstract
Race car drivers are often hypohydrated during a race. The FluidLogic drink system is a hands-free, prompted drinking system that is hypothesized to increase the likeliness of drivers' consuming fluids and thereby mitigating hypohydration. To test the hypothesis, 20 elite professional race car drivers participated in a 2-day cross-over study in which they drove on a race simulator in an environmental chamber that was heated to regulation cockpit temperature (38°C). Drivers used either the FluidLogic drink system or a standard in-car water bottle system (Control) on one of each testing day. The results indicated that there was consistent fluid consumption with the FluidLogic system, while the Control condition elicited fluid consumption in bolus doses. The Control condition was associated with moderate (0.5%) increased core body temperature (P < 0.05) and substantial (3.3%) increased urine-specific gravity (P < 0.001) as compared to the FluidLogic condition. Driving performance metrics indicated that lap times during the Control Condition were 5.1 ± 1.4 (4.1%) seconds slower (P < 0.05) than the FluidLogic Condition, due to driving errors that occurred in the high-speed corners. Based on these results, prompted hands-free drinking can mitigate hypohydration and performance loss in automobile racing drivers.
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Affiliation(s)
- David P Ferguson
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
| | - Paul R Alex
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
| | - Julia M Castrucci
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
| | - Annabella M Akouri
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
| | | | - Jacob D Danes
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
| | - Faith L Houck
- Department of Kinesiology, Michigan State University, East Lansing, Michigan, USA
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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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Manning CN, Benjamin CL, Sekiguchi Y, Butler CR, Szymanski MR, Stearns RL, Armstrong LE, Lee EC, Casa DJ. Environmental Stress Symptoms during Heat Acclimatization, Heat Acclimation, and Intermittent Heat Training. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3219. [PMID: 36833912 PMCID: PMC9962616 DOI: 10.3390/ijerph20043219] [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: 01/11/2023] [Revised: 02/09/2023] [Accepted: 02/10/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Athletes training in heat experience physiological and perceptual symptoms that risk their safety and performance without adaptation. PURPOSE We examined the changes in environmental symptoms, assessed with the Environmental Symptoms Questionnaire (ESQ), during heat acclimatization (HAz), heat acclimation (HA), and intermittent heat training (HT). METHODS Twenty-seven participants (mean ± standard deviation [M ± SD], age of 35 ± 12 y, VO2max of 57.7 ± 6.8 mL·kg-1·min-1) completed five trials involving 60 mins of running (60% vVO2max) followed by a 4 km time trial in heat (M ± SD, temperature of 35.5 ± 0.7 °C, humidity of 46.4 ± 1.5%). The trials occurred at baseline, post-HAz, post-HA, at week 4 of HT (post-HT4), and at week 8 of HT (post-HT8). The participants completed HT once/week (HTMIN), completed HT twice/week (HTMAX), or did not complete HT (HTCON). ESQ symptoms, thermal sensation (TS), and heart rate (HR) were measured pre- and post-trial. RESULTS Post-ESQ symptoms improved post-HA (3[0.40, 4.72], p = 0.02) and post-HAz (3[0.35, 5.05], p = 0.03) from baseline. During HT, symptoms improved in the HTMAX group and worsened in the HTMIN and HTCON groups. Symptoms improved in the HTMAX group versus the HTCON group at post-HT8 (4[1.02, 7.23], p = 0.012). Higher TS and HR values were weakly associated with ESQ symptoms during HT (r = 0.20, p = 0.04), only explaining 20% of variance. CONCLUSIONS ESQ symptoms improved during HAz, HA, and HT 2x/week. ESQ symptoms were not statistically correlated with HR during exercise heat stress. TS was not sensitive to detecting adaptation and did not subjectively change. The ESQ may be valuable in monitoring adaptation and may contribute to performance post-acclimation.
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Affiliation(s)
- Ciara N. Manning
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
| | - Courteney L. Benjamin
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
- Department of Kinesiology, Samford University, Birmingham, AL 35226, USA
| | - Yasuki Sekiguchi
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
- Sports Performance Lab, Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX 79430, USA
| | - Cody R. Butler
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
- Special Warfare Human Performance Squadron, Lackland Air Force Base, San Antonio, TX 78236, USA
| | - Michael R. Szymanski
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
| | - Rebecca L. Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
| | - Lawrence E. Armstrong
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
| | - Elaine C. Lee
- Human Performance Lab, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
| | - Douglas J. Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT 06269, USA
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Heishman AD, Daub BD, Miller RM, Freitas EDS, Bemben MG. Longitudinal Hydration Assessment in Collegiate Basketball Players Over Various Training Phases. J Strength Cond Res 2021; 35:1089-1094. [PMID: 30272627 DOI: 10.1519/jsc.0000000000002845] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Heishman, AD, Daub, BD, Miller, RM, Freitas, EDS, and Bemben, MG. Longitudinal hydration assessment in collegiate basketball players over various training phases. J Strength Cond Res 35(4): 1089-1094, 2021-To the best of our knowledge, previous literature has not longitudinally examined hydration status in collegiate basketball players. Therefore, the purpose of this investigation was to examine the prepractice hydration status of collegiate basketball players across various training phases for 2 consecutive years. Retrospective analyses examined prepractice urine-specific gravity (USG) assessments obtained from National Collegiate Athletic Association (NCAA) Division I male basketball players during the preseason and competitive season, for 2 consecutive years. The first year (year 1 = Y1) of analysis consisted of 15 athletes and the second year (year 2 = Y2) consisted of 16 athletes, with 8 athletes in both seasons. Hydration status was classified based on the National Athletic Trainers' criteria: (a) euhydrated, USG < 1.020; (b) hypohydrated, USG = 1.020-1.030; and (c) significantly hypohydrated, USG > 1.030. Additional comparisons examined the association of minutes played with hydration status and changes in hydration status for athletes returning from Y1 to Y2. The results indicated 55-65.7% of cases showed levels of significant hypohydration during the preseason and competitive seasons for both years. Preseason hydration status was significantly better than the competitive season (Y1, p = 0.008; Y2, p = 0.005). Despite significant differences in minutes played (p < 0.001), no differences in hydration status were observed. Returning athletes displayed no differences in hydration status between Y1 and Y2. Collegiate basketball players show levels of hypohydration when longitudinally examined across various training phases. Although hydration may be improved in the preseason, alternative factors such as average game minutes played and length in program may not influence hydration status.
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Affiliation(s)
- Aaron D Heishman
- Departments of Health and Exercise Science; and.,Athletics, Basketball Strength and Performance, University of Oklahoma, Norman, Oklahoma
| | - Bryce D Daub
- Athletics, Basketball Strength and Performance, University of Oklahoma, Norman, Oklahoma
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11
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O'Connor PJ. Pain During a Marathon Run: Prevalence and Correlates in a Cross-Sectional Study of 1,251 Recreational Runners in 251 Marathons. Front Sports Act Living 2021; 3:630584. [PMID: 33644755 PMCID: PMC7902858 DOI: 10.3389/fspor.2021.630584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 01/11/2021] [Indexed: 11/26/2022] Open
Abstract
This cross-sectional study aimed to obtain fundamental knowledge about pain during a marathon run. During the first seven months of 2007, announcements on websites of interest to marathon runners were used to recruit participants. A total of 1,251 runners (550 female runners) completed a 41-question online survey about the location and intensity of their primary pain during their last marathon and potentially related variables [perception of effort during the marathon, number of prior marathons run, typical pain intensity during training runs, percentage of training days with run-induced pain, highest intensity pain ever experienced]. Pain location was selected from a list of 27 specified body sites covering the entire body. Kilometer at which pain first occurred indexed pain threshold. Pain intensity at the primary location of pain was measured with a standardized, well-validated 0–10 pain intensity scale. Pearson correlations and multiple regression quantified the associations between average pain intensity and other variables. Sex-related differences in pain were tested using independent t-tests. Effort ratings (6–20) were added as a covariate in an ANCOVA to test if perceived effort accounted for possible sex-related differences in pain. Based on the available research, it was hypothesized that: (i) most runners would report moderate intensity pain, (ii) pain would be associated with both exercise intensity during the marathon and pain during training, and (iii) after adjusting for expected sex-related differences in perceived effort, females would experience pain earlier and rate the pain intensity as higher. All but two runners (99.8%) reported pain during a marathon, and most frequently in the anterior/medial thigh (17.1%), hamstring (10%), and calf (9.3%) locations. Pain threshold occurred at 25.3 ± 9.8 km (15.7 ± 6.1 miles) and the overall pain intensity of the run was 5.26 ± 2.45. No sex-related pain differences were found. Overall pain intensity during a marathon was significantly associated with: pain intensity during training runs (r = 0.39), percentage of training days with run-induced pain (r = 0.23), highest intensity pain ever experienced (r = 0.23), number of prior marathons (r = −0.18), and intensity of effort (r = 0.11) (all P < 0.001). Most runners experience moderate to very strong intensity pain during a marathon; the pain was independent of biological sex, and the pain is weakly associated with marathon race experience, pain during training, race effort, and the highest intensity of pain ever experienced.
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Affiliation(s)
- Patrick J O'Connor
- Department of Kinesiology, University of Georgia, Athens, GA, United States
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12
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Adams WM, Scarneo-Miller SE, Vandermark LW, Belval LN, DiStefano LJ, Lee EC, Armstrong LE, Casa DJ. Movement Technique and Standing Balance After Graded Exercise-Induced Dehydration. J Athl Train 2021; 56:203-210. [PMID: 33449078 DOI: 10.4085/1062-6050-0436.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Hypohydration has been shown to alter neuromuscular function. However, the longevity of these impairments remains unclear. OBJECTIVE To examine the effects of graded exercise-induced dehydration on neuromuscular control 24 hours after exercise-induced hypohydration. DESIGN Crossover study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS A total of 23 men (age = 21 ± 2 years, height = 179.8 ± 6.4 cm, mass = 75.24 ± 7.93 kg, maximal oxygen uptake [VO2max] = 51.7 ± 5.5 mL·kg-1·min-1, body fat = 14.2% ± 4.6%). INTERVENTION(S) Participants completed 3 randomized exercise trials: euhydrated arrival plus fluid replacement (EUR), euhydrated arrival plus no fluid (EUD), and hypohydrated arrival plus no fluid (HYD) in hot conditions (ambient temperature = 35.2°C ± 0.6°C, relative humidity = 31.3% ± 2.5%). Each trial consisted of 180 minutes of exercise (six 30-minute cycles: 8 minutes at 40% VO2max; 8 minutes, 60% VO2max; 8 minutes, 40% VO2max; 6 minutes, passive rest) followed by 60 minutes of passive recovery. MAIN OUTCOME MEASURE(S) We used the Landing Error Scoring System and Balance Error Scoring System (BESS) to measure movement technique and postural control at pre-exercise, postexercise and passive rest (POSTEX), and 24 hours postexercise (POST24). Differences were assessed using separate mixed-design (trial × time) repeated-measures analyses of variance. RESULTS The magnitude of hypohydration at POSTEX was different among EUR, EUD, and HYD trials (0.2% ± 1%, 3.5% ± 1%, and 5% ± 0.9%, respectively; P < .05). We observed no differences in Landing Error Scoring System scores at pre-exercise (2.9 ± 1.6, 3.0 ± 2.1, 3.0 ± 2.0), POSTEX (3.3 ± 1.5, 3.0 ± 2.0, 3.1 ± 1.9), or POST24 (3.3 ± 1.9, 3.2 ± 1.4, 3.3 ± 1.6) among the EUD, EUR, and HYD trials, respectively (P = .90). Hydration status did not affect BESS scores (P = .11), but BESS scores at POSTEX (10.4 ± 1.1) were greater than at POST24 (7.7 ± 0.9; P = .03). CONCLUSIONS Whereas exercise-induced dehydration up to 5% body mass did not impair movement technique or postural control 24 hours after a prolonged bout of exercise in a hot environment, postural control was impaired at 60 minutes after prolonged exercise in the heat. Consideration of the length of recovery time between bouts of exercise in hot environments is warranted.
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Affiliation(s)
- William M Adams
- Department of Kinesiology, University of North Carolina at Greensboro
| | - Samantha E Scarneo-Miller
- Korey Stringer Institute, University of Connecticut, Storrs.,Department of Kinesiology, University of Connecticut, Storrs
| | - Lesley W Vandermark
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville
| | - Luke N Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, University of Texas Southwestern Medical Center
| | | | - Elaine C Lee
- Department of Kinesiology, University of Connecticut, Storrs
| | | | - Douglas J Casa
- Korey Stringer Institute, University of Connecticut, Storrs.,Department of Kinesiology, University of Connecticut, Storrs
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13
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Abed MEF, Deshayes TA, Claveau P, Jeker D, Thénault F, Goulet ED. Impact of Mild Hypohydration on 100 m Front Crawl Performance and Starting Block Peak Force Production in Competitive University-Level Swimmers. Sports (Basel) 2020; 8:sports8100133. [PMID: 33066345 PMCID: PMC7602092 DOI: 10.3390/sports8100133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 10/06/2020] [Accepted: 10/09/2020] [Indexed: 11/29/2022] Open
Abstract
Unstructured, ad libitum drinking may predispose some athletes to start exercise already slightly hypohydrated (decreased body water). The impact of pre-exercise mild hypohydration on subsequent swimming performance is still unknown. Hence, the goal of this study was to examine its effect on peak force production on the starting block and 100 m front crawl swimming performance in competitive university-level swimmers. At least one hour after having been passively exposed to heat where a body mass loss of 1.5% was induced or euhydration (normal body water) maintained, nine participants (age: 22 ± 2 years) underwent an assessment of their peak force production on the starting block and 100 m front crawl performance. One hour following hypohydration, rectal temperature had returned to baseline in each condition. Urine osmolality and specific gravity were higher (p < 0.05) with hypohydration than euhydration (995 ± 65 vs. 428 ± 345 mOsmol/kg; 1.027 ± 0.003 vs. 1.016 ± 0.007 g/mL) prior to exercise testing, as was perceived thirst. Swimming performance (p = 0.86) and peak force production (p = 0.72) on the starting block did not differ between the hypohydration and euhydrated condition (63.00 ± 4.26 vs. 63.09 ± 4.52 s; 1322 ± 236 vs. 1315 ± 230 N). The current results indicate that mild hypohydration, which may occur with ad libitum drinking, does not impede peak force production on the starting block and 100 m front crawl performance in university-level competitive swimmers. Planned drinking is not required prior to such an event.
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Affiliation(s)
- Mohamed El Fethi Abed
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - Thomas A. Deshayes
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
- Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC J1H 4C4, Canada
| | - Pascale Claveau
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - David Jeker
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - François Thénault
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
| | - Eric D.B. Goulet
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC J1K 2R1, Canada; (M.E.F.A.); (T.A.D.); (P.C.); (D.J.); (F.T.)
- Research Centre on Aging, University of Sherbrooke, Sherbrooke, QC J1H 4C4, Canada
- Correspondence: ; Tel.: +1-819-821-8000 (ext. 62728)
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14
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Williams D, Fazenda B, Williamson V, Fazekas G. On Performance and Perceived Effort in Trail Runners Using Sensor Control to Generate Biosynchronous Music. SENSORS 2020; 20:s20164528. [PMID: 32823519 PMCID: PMC7472014 DOI: 10.3390/s20164528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/20/2020] [Accepted: 07/30/2020] [Indexed: 12/19/2022]
Abstract
Music has been shown to be capable of improving runners’ performance in treadmill and laboratory-based experiments. This paper evaluates a generative music system, namely HEARTBEATS, designed to create biosignal synchronous music in real-time according to an individual athlete’s heartrate or cadence (steps per minute). The tempo, melody, and timbral features of the generated music are modulated according to biosensor input from each runner using a combination of PPG (Photoplethysmography) and GPS (Global Positioning System) from a wearable sensor, synchronized via Bluetooth. We compare the relative performance of athletes listening to music with heartrate and cadence synchronous tempos, across a randomized trial (N = 54) on a trail course with 76 ft of elevation. Participants were instructed to continue until their self-reported perceived effort went beyond an 18 using the Borg rating of perceived exertion. We found that cadence-synchronous music improved performance and decreased perceived effort in male runners. For female runners, cadence synchronous music improved performance but it was heartrate synchronous music which significantly reduced perceived effort and allowed them to run the longest of all groups tested. This work has implications for the future design and implementation of novel portable music systems and in music-assisted coaching.
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Affiliation(s)
- Duncan Williams
- School of Computing, Science & Engineering, the University of Salford, the Crescent, Salford M5 4WT, UK;
- Correspondence:
| | - Bruno Fazenda
- School of Computing, Science & Engineering, the University of Salford, the Crescent, Salford M5 4WT, UK;
| | | | - György Fazekas
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London E1 4FZ, UK;
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15
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James LJ, Funnell MP, James RM, Mears SA. Does Hypohydration Really Impair Endurance Performance? Methodological Considerations for Interpreting Hydration Research. Sports Med 2020; 49:103-114. [PMID: 31696453 PMCID: PMC6901416 DOI: 10.1007/s40279-019-01188-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The impact of alterations in hydration status on human physiology and performance responses during exercise is one of the oldest research topics in sport and exercise nutrition. This body of work has mainly focussed on the impact of reduced body water stores (i.e. hypohydration) on these outcomes, on the whole demonstrating that hypohydration impairs endurance performance, likely via detrimental effects on a number of physiological functions. However, an important consideration, that has received little attention, is the methods that have traditionally been used to investigate how hypohydration affects exercise outcomes, as those used may confound the results of many studies. There are two main methodological limitations in much of the published literature that perhaps make the results of studies investigating performance outcomes difficult to interpret. First, subjects involved in studies are generally not blinded to the intervention taking place (i.e. they know what their hydration status is), which may introduce expectancy effects. Second, most of the methods used to induce hypohydration are both uncomfortable and unfamiliar to the subjects, meaning that alterations in performance may be caused by this discomfort, rather than hypohydration per se. This review discusses these methodological considerations and provides an overview of the small body of recent work that has attempted to correct some of these methodological issues. On balance, these recent blinded hydration studies suggest hypohydration equivalent to 2–3% body mass decreases endurance cycling performance in the heat, at least when no/little fluid is ingested.
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Affiliation(s)
- Lewis J James
- School of Sport, Exercise and Health Sciences, National Centre for Sport and Exercise Medicine, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK.
| | - Mark P Funnell
- School of Sport, Exercise and Health Sciences, National Centre for Sport and Exercise Medicine, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
| | - Ruth M James
- Sport, Health and Performance Enhancement Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Stephen A Mears
- School of Sport, Exercise and Health Sciences, National Centre for Sport and Exercise Medicine, Loughborough University, Loughborough, Leicestershire, LE11 3TU, UK
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16
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Lipman GS, Gaudio FG, Eifling KP, Ellis MA, Otten EM, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2019 Update. Wilderness Environ Med 2019; 30:S33-S46. [DOI: 10.1016/j.wem.2018.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/04/2018] [Accepted: 10/22/2018] [Indexed: 10/26/2022]
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17
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Park S, Alencar M, Sassone J, Madrigal L, Ede A. Self-reported methods of weight cutting in professional mixed-martial artists: how much are they losing and who is advising them? J Int Soc Sports Nutr 2019; 16:52. [PMID: 31718652 PMCID: PMC6849211 DOI: 10.1186/s12970-019-0320-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 10/16/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Similar to other combat sports, mixed martial arts (MMA) includes divisional weight classes. The purpose of our research was to further investigate the amount of weight professional MMA fighters lost prior to weighing in for competition, their methods used to cut weight, and their sources of advice on how to cut weight. METHODS This survey was administered to 92 male professional MMA athletes. The survey questions included duration of overall weight loss prior to competition, methods of weight-cutting, and their sources of advice regarding weight cutting. RESULTS When comparing the number of methods of weight cutting with the source of advice, those who received their advice from social media used slightly more methods of weight cutting (M = 4.86, SD = 1.27) than those who did not (M = 4.02, SD = 1.55); t(90) = - 2.53, p < .05. MMA athletes that used the help of a registered dietitian nutritionist also reported using the least amount of methods for weight-cutting than any other category (M = 3.84, SD = 1.67). Those that used teammates and did not use a registered dietitian nutritionist used slightly more methods (M = 4.46, SD = 1.41) than those who used a registered dietitian nutritionist. CONCLUSIONS The findings of this study report that professional MMA athletes do undergo rapid weight loss through various methods to make weight for competition. This study adds evidence to the literature that most professional MMA athletes undergo RWL for competition without the guidance of a registered dietitian nutritionist. It is unclear what the effect of using a registered dietitian nutritionist may have on an MMA athletes' ability to reduce weight in a safe and effective manner. Future research should seek to investigate if employing a registered dietitian nutritionist may lead to a higher rate of success for MMA athletes to make weight, and help reduce adverse risks of RWL.
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Affiliation(s)
- Sungjun Park
- Department of Kinesiology, California State University, Long Beach, Long Beach, CA, USA. .,Fitness & Integrated Training Laboratory and Sport Studies & Sport Psychology Laboratory, Long Beach, USA.
| | - Michelle Alencar
- Department of Kinesiology, California State University, Long Beach, Long Beach, CA, USA.,Fitness & Integrated Training Laboratory and Sport Studies & Sport Psychology Laboratory, Long Beach, USA
| | - John Sassone
- Department of Family and Consumer Science, Nutrition and Dietetics, California State University, Long Beach, USA
| | - Leilani Madrigal
- Department of Kinesiology, California State University, Long Beach, Long Beach, CA, USA.,Fitness & Integrated Training Laboratory and Sport Studies & Sport Psychology Laboratory, Long Beach, USA
| | - Alison Ede
- Department of Kinesiology, California State University, Long Beach, Long Beach, CA, USA.,Fitness & Integrated Training Laboratory and Sport Studies & Sport Psychology Laboratory, Long Beach, USA
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18
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Giersch GEW, Charkoudian N, Stearns RL, Casa DJ. Fluid Balance and Hydration Considerations for Women: Review and Future Directions. Sports Med 2019; 50:253-261. [DOI: 10.1007/s40279-019-01206-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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19
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O’Connell SM, Woodman RJ, Brown IL, Vincent DJ, Binder HJ, Ramakrishna BS, Young GP. Comparison of a sports-hydration drink containing high amylose starch with usual hydration practice in Australian rules footballers during intense summer training. J Int Soc Sports Nutr 2018; 15:46. [PMID: 30241477 PMCID: PMC6150988 DOI: 10.1186/s12970-018-0253-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/14/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fluid deficits exceeding 1.6% can lead to physical and cognitive impairment in athletes. Sport drinks used by athletes are often hyper-osmolar but this is known to be suboptimal for rehydration in medical settings and does not utilize colonic absorptive capacity. Colonic absorption can be enhanced by fermentative production of short chain fatty acids (SCFA) from substrates such as high amylose maize starch (HAMS). This study therefore compared, in elite Australian Football League (AFL) players at the height of outdoor summer training, a novel dual-action sports oral rehydration strategy that contained HAMS as well as glucose, to their usual rehydration practices (Control). The primary outcome markers of hydration were hematocrit and body weight. METHODS A randomized single-blind crossover study was undertaken in thirty-one AFL players; twenty-seven completed the study which was conducted on four days (two days in the Intervention arm and two in Control arm). The Intervention arm was comprised a 50-100 g evening preload of an acetylated HAMS (Ingredion Pty Ltd) followed by consumption of a specially formulated sports oral rehydration solution (SpORS) drink during intense training and recovery. Players followed their usual hydration routine in the Control arm. Quantitative assessments of body weight, hematocrit and urine specific gravity were made at three time-points on each day of training: pre-training, post-training (90 min), and at end of recovery (30-60 min later). GPS tracking monitored player exertion. RESULTS Across the three time-points, hematocrit was significantly lower and body weight significantly higher in Intervention compared to Control arms (p < 0.02 and p = 0.001 respectively, mixed effects model). Weights were significantly heavier at all three assessment points for Intervention compared to Control arms (Δ = 0.30 ± 0.13, p = 0.02 pre-training; Δ = 0.43 ± 0.14, p = 0.002 post training; and Δ = 0.68 ± 0.14, p < 0.001 for recovery). Between the pre-training and end-of-recovery assessments, the Control arm lost 0.80 kg overall compared with 0.12 kg in the Intervention arm, an 85% lower reduction of bodyweight across the assessment period. CONCLUSION The combination of the significantly lower hematocrit and increased body weight in the Intervention arm represents better hydration not only at the end of training as well as following a recovery period but also at its commencement. The magnitude of the benefit seems sufficient to have an impact on performance and further studies to test this possibility are now indicated. TRIAL REGISTRATION Trial is listed on the Australian New Zealand Clinical Trials Registry ( ACTRN 12613001373763 ).
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Affiliation(s)
| | - Richard John Woodman
- Flinders Centre for Epidemiology and Biostatistics, Flinders University, GPO Box 2100, 5001 Adelaide, Australia
| | - Ian Lewis Brown
- Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA Australia
| | | | - Henry Joseph Binder
- Department of Internal Medicine, Yale School of Medicine, P.O. Box 208019, New Haven, CT 06520 USA
| | | | - Graeme Paul Young
- Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA Australia
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20
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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: 190] [Impact Index Per Article: 27.1] [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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21
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Shearer J, Graham TE, Skinner TL. Nutra-ergonomics: influence of nutrition on physical employment standards and the health of workers. Appl Physiol Nutr Metab 2017; 41:S165-74. [PMID: 27277565 DOI: 10.1139/apnm-2015-0531] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The importance of ergonomics across several scientific domains, including biomechanics, psychology, sociology, and physiology, have been extensively explored. However, the role of other factors that may influence the health and productivity of workers, such as nutrition, is generally overlooked. Nutra-ergonomics describes the interface between workers, their work environment, and performance in relation to their nutritional status. It considers nutrition to be an integral part of a safe and productive workplace that encompasses physical and mental health as well as the long-term wellbeing of workers. This review explores the knowledge, awareness, and common practices of nutrition, hydration, stimulants, and fortified product use employed prior to physical employment standards testing and within the workplace. The influence of these nutra-ergonomic strategies on physical employment standards, worker safety, and performance will be examined. Further, the roles, responsibilities, and implications for the applicant, worker, and the employer will be discussed within the context of nutra-ergonomics, with reference to the provision and sustainability of an environment conducive to optimize worker health and wellbeing. Beyond physical employment standards, workplace productivity, and performance, the influence of extended or chronic desynchronization (irregular or shift work) in the work schedule on metabolism and long-term health, including risk of developing chronic and complex diseases, is discussed. Finally, practical nutra-ergonomic strategies and recommendations for the applicant, worker, and employer alike will be provided to enhance the short- and long-term safety, performance, health, and wellbeing of workers.
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Affiliation(s)
- Jane Shearer
- a Department of Biochemistry and Molecular Biology, Cumming School of Medicine. Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Terry E Graham
- b Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Tina L Skinner
- c Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, Queensland QLD 4072, Australia
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22
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Adams WM, Hosokawa Y, Belval LN, Huggins RA, Stearns RL, Casa DJ. Deviation from goal pace, body temperature and body mass loss as predictors of road race performance. J Sci Med Sport 2016; 20:302-306. [PMID: 27720128 DOI: 10.1016/j.jsams.2016.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/03/2016] [Accepted: 07/28/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVES The purpose of this study was to examine the relationship between pacing, gastrointestinal temperature (TGI), and percent body mass loss (%BML) on relative race performance during a warm weather 11.3km road race. DESIGN Observational study of a sample of active runners competing in the 2014 Falmouth Road Race. METHODS Participants ingested a TGI pill and donned a GPS enabled watch with heart rate monitoring capabilities prior to the start of the race. Percent off predicted pace (%OFF) was calculated for seven segments of the race. Separate linear regression analyses were used to assess the relationship between pace, TGI, and %BML on relative race performance. One-way ANOVA was used to analyse post race TGI (≥40°C vs <40°C) on pace and %OFF. RESULTS Larger %BML was associated with faster finish times (R2=0.19, p=0.018), faster average pace (R2=0.29, p=0.012), and a greater %OFF (R2=0.15, p=0.033). %OFF during the first mile (1.61km) significantly predicted overall finish time (R2=0.64, p<0.001) while %OFF during the second mile (3.22km) (R2 change=0.18, p<0.001) further added to the model (R2=0.82, p<0.001). Body temperature (pre race TGI and post race TGI) was not predictive of overall finish time (p>0.05). There was a trend in a slower pace (p=0.055) and greater %OFF (p=0.056) in runners finishing the race with a TGI>40°C. CONCLUSIONS Overall, finish time was influenced by greater variations in pace during the first two miles of the race. In addition, runners who minimized fluid losses and had lower TGI were associated with meeting self-predicted goals.
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Affiliation(s)
- William M Adams
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, United States.
| | - Yuri Hosokawa
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, United States
| | - Luke N Belval
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, United States
| | - Robert A Huggins
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, United States
| | - Rebecca L Stearns
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, United States
| | - Douglas J Casa
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, United States
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Pryor RR, Bennett BL, O'Connor FG, Young JMJ, Asplund CA. Medical Evaluation for Exposure Extremes: Heat. Wilderness Environ Med 2016; 26:S69-75. [PMID: 26617381 DOI: 10.1016/j.wem.2015.09.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Exertional heat illness can be a serious consequence of sports or exercise in hot environments. Participants can possess intrinsic or face extrinsic risk factors that may increase their risk for heat-related illness. Knowledge of the physiology and pathology of heat illness, identification of risk factors, and strategies to combat heat accumulation will aid both the practitioner and the participant in preparing for activities that occur in hot environments. Through preparation and mitigation of risk, safe and enjoyable wilderness adventure can be pursued.
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Affiliation(s)
- Riana R Pryor
- Department of Kinesiology, Korey Stringer Institute, University of Connecticut, Storrs, Connecticut (Dr Pryor).
| | - Brad L Bennett
- Military & Emergency Medicine Department, F. Hébert School of Medicine, Bethesda, Maryland (Dr Bennett); Uniformed Services University of the Health Sciences, Bethesda, Maryland (Drs Bennett and O'Connor)
| | - Francis G O'Connor
- Uniformed Services University of the Health Sciences, Bethesda, Maryland (Drs Bennett and O'Connor)
| | - Justin M J Young
- Department of Family Medicine and Community Health, Division of Sports Medicine, John A. Burns School of Medicine, University of Hawaii, Mililani, Hawaii (Dr Young)
| | - Chad A Asplund
- Department of Family Medicine, Georgia Regents University, Augusta, Georgia (Dr Asplund)
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24
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Casa DJ, DeMartini JK, Bergeron MF, Csillan D, Eichner ER, Lopez RM, Ferrara MS, Miller KC, O'Connor F, Sawka MN, Yeargin SW. National Athletic Trainers' Association Position Statement: Exertional Heat Illnesses. J Athl Train 2016; 50:986-1000. [PMID: 26381473 DOI: 10.4085/1062-6050-50.9.07] [Citation(s) in RCA: 319] [Impact Index Per Article: 39.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To present best-practice recommendations for the prevention, recognition, and treatment of exertional heat illnesses (EHIs) and to describe the relevant physiology of thermoregulation. BACKGROUND Certified athletic trainers recognize and treat athletes with EHIs, often in high-risk environments. Although the proper recognition and successful treatment strategies are well documented, EHIs continue to plague athletes, and exertional heat stroke remains one of the leading causes of sudden death during sport. The recommendations presented in this document provide athletic trainers and allied health providers with an integrated scientific and clinically applicable approach to the prevention, recognition, treatment of, and return-to-activity guidelines for EHIs. These recommendations are given so that proper recognition and treatment can be accomplished in order to maximize the safety and performance of athletes. RECOMMENDATIONS Athletic trainers and other allied health care professionals should use these recommendations to establish onsite emergency action plans for their venues and athletes. The primary goal of athlete safety is addressed through the appropriate prevention strategies, proper recognition tactics, and effective treatment plans for EHIs. Athletic trainers and other allied health care professionals must be properly educated and prepared to respond in an expedient manner to alleviate symptoms and minimize the morbidity and mortality associated with these illnesses.
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Affiliation(s)
| | | | | | | | - E Randy Eichner
- University of Oklahoma Health Sciences Center, Oklahoma City
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25
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Davis JK, Laurent CM, Allen KE, Green JM, Stolworthy NI, Welch TR, Nevett ME. Influence of Dehydration on Intermittent Sprint Performance. J Strength Cond Res 2016; 29:2586-93. [PMID: 25774626 DOI: 10.1519/jsc.0000000000000907] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined the effects of dehydration on intermittent sprint performance and perceptual responses. Eight male collegiate baseball players completed intermittent sprints either dehydrated (DEHY) by 3% body mass or euhydrated (EU). Body mass was reduced through exercise in the heat with controlled fluid restriction occurring 1 day before the trial. Participants completed twenty-four 30-m sprints divided into 3 bouts of 8 sprints with 45 seconds of rest between each sprint and 3 minutes between each bout. Perceived recovery status (PRS) scale was recorded before the start of each trial. Heart rate (HR), ratings of perceived exertion (RPE) (0-10 OMNI scale), and perceived readiness (PR) scale were recorded after every sprint, and session RPE (SRPE) was recorded 20 minutes after completing the entire session. A 2 (condition) × 3 (bout of sprints) repeated-measures ANOVA revealed a significant main effect of condition on mean sprint time (p = 0.03), HR (p < 0.01), RPE (p = 0.01), and PR (p = 0.02). Post hoc tests showed significantly faster mean sprint times for EU vs. DEHY during the second (4.87 ± 0.29 vs. 5.03 ± 0.33 seconds; p = 0.01) and third bouts of sprints (4.91 ± 0.29 vs. 5.12 ± 0.44 seconds; p = 0.02). Heart rate was also significantly lower (p ≤ 0.05) for EU during the second and third bouts. Post hoc measures also showed significantly impaired (p ≤ 0.05) feelings of recovery (PRS) before exercise and increased (p ≤ 0.05) perceptual strain before each bout (PR) during the second and third bouts of repeated sprint work (i.e., RPE and PR) and after the total session (SRPE) in the DEHY condition. Dehydration impaired sprint performance, negatively altered perception of recovery status before exercise, and increased RPE and HR response.
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Affiliation(s)
- Jon-Kyle Davis
- 1Department of Kinesiology, University of Montevallo, Montevallo, Alabama; 2Exercise Science Program, Bowling Green State University, Bowling Green, Ohio; 3Department of Health, Physical Education and Recreation, the University of North Alabama, Florence, Alabama; and 4Department of Physical Education and Exercise Science, University of South Florida, Tampa, Florida
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26
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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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27
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Brown JS, Connolly DA. Selected human physiological responses during extreme heat: the Badwater Ultramarathon. J Strength Cond Res 2016; 29:1729-36. [PMID: 25463692 DOI: 10.1519/jsc.0000000000000787] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this article was to examine various physiological responses during an ultramarathon held in extreme heat. Our investigation was conducted at The Badwater Ultramarathon, a nonstop 217-km run across Death Valley, CA, USA. This study recruited 4 male athletes, average age of 43 (±SD) (±7.35), (range) 39-54 years. All 4 subjects successfully completed the race with a mean finish time of 36:20:23 hours (±SD) (±3:08:38) (range) 34:05:25-40:51:46 hours, and a mean running speed of 6.03 km·h(-1) (±SD) (±0.05), (range) 5.3-6.4 km·h(-1). The anthropometric variables measured were (mean, ±SD) mass 79.33 kg (±6.43), height 1.80 m (±0.09), body surface area 1.93 m2 (±0.16), body mass index 24.38 kg·m(-2) (±1.25), fat mass 13.88% (±2.29), and body water 62.08% (±1.56). Selected physiological variables measured were core body temperature, skin temperature, heart rate, breathing rate, and blood pressure. Rate of perceived intensity, rate of thermal sensation, and environmental factors were also monitored. Our study found (mean and ±SD) core body temperature 37.49° C (±0.88); skin temperature 31.13° C (±3.06); heart rate 106.79 b·min(-1) (±5.11); breathing rate 36.55 b·min(-1) (±0.60); blood pressure 128/86 mm Hg (±9.24/4.62); rate of perceived intensity 5.49 (±1.26); rate of thermal sensation 4.69 (±0.37); daytime high temperature of 46.6° C, and a mean temperature of 28.35° C. Our fastest finisher demonstrated a lower overall core body temperature (36.91° C) when compared with the group mean (37.49° C). In contrast to previous findings, our data show that the fastest finisher demonstrates a lower overall core body temperature. We conclude that it may be possible that a time threshold exists whereby success in longer duration events requires an ability to maintain a lower core body temperature vs. tolerating a higher core body temperature.
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Affiliation(s)
- Jacqueline S Brown
- Department of Physical Education, The University of Vermont, Burlington, Vermont
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Iglesia I, Santaliestra-Pasías AM, Bel-Serrat S, Sadalla-Collese T, Miguel-Berges ML, Moreno LA. Fluid consumption, total water intake and first morning urine osmolality in Spanish adolescents from Zaragoza: data from the HELENA study. Eur J Clin Nutr 2015; 70:541-7. [PMID: 26669573 DOI: 10.1038/ejcn.2015.203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 09/28/2015] [Accepted: 10/26/2015] [Indexed: 11/09/2022]
Abstract
BACKGROUND/OBJECTIVES The objective of the study is to describe the hydration status and to assess the main food- and/or fluid intake-associated factors in healthy adolescents. SUBJECTS/METHODS A total of 194 adolescents from the city of Zaragoza aged 12.5-17.5 years (99 males) participating in the 'Healthy Lifestyle in Europe by Nutrition in Adolescence' (HELENA) cross-sectional study were included. First morning urine was collected, and osmolality was determined by freezing point depression osmometer. A self-reported computer-based 24-h dietary recall was applied the same day of the urine collection. Analysis of variance, Kruskal-Wallis procedure or Pearson's χ(2) analyses was used to examine the group associations. RESULTS Seventy-one percent of adolescents did not meet the European Food Safety Agency (EFSA) recommendations for average total water intake (TWI), and 68% had high first morning urine osmolality values. TWI and the proportion of those meeting EFSA reference values significantly (P<0.05) decreased with increased osmolality. Males who met the EFSA recommendations consumed significantly (P<0.05) more plain water (1035.13 vs 582.68 ml) and dairy drinks (368.13 vs 226.68 ml) than those who did not. In females, the consumption of water (1359.41 vs 620.44 ml) and sugar-sweetened beverages (214.61 vs 127.42 ml) was significantly higher in those meeting the EFSA recommendations than in those who did not. First morning urine osmolality was associated with vegetables (unstandardized β: -0.6; 95% confidence interval (CI): -1.02 and -0.18) and fruits intake (β: -0.41; 95% CI: -0.63 and -0.19) in males and with dairy drinks (β: -0.39; 95% CI: -0.76 and -0.02) and fruits (β: -0.41; 95% CI: -0.73 and -0.10) in females. CONCLUSIONS There was a high prevalence of inadequate TWI and high urine osmolality among these Spanish adolescents. Lower urine osmolality was associated with higher consumption of vegetables in males, dairy drinks in females and fruits in both males and females.
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Affiliation(s)
- I Iglesia
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain.,Facultad de Ciencias de la Salud, University of Zaragoza, Zaragoza, Spain
| | - A M Santaliestra-Pasías
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain.,Facultad de Ciencias de la Salud, University of Zaragoza, Zaragoza, Spain.,Red de Salud Materno Infantil y del Desarrollo (RED SAMID), Instituto Carlos III, Madrid, Spain
| | - S Bel-Serrat
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain
| | - T Sadalla-Collese
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain.,Department of Preventive Medicine, School of Medicine of the University of São Paulo, São Paulo/SP, Brazil
| | - M L Miguel-Berges
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain.,Facultad de Ciencias de la Salud, University of Zaragoza, Zaragoza, Spain
| | - L A Moreno
- GENUD (Growth, Exercise, Nutrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain.,Facultad de Ciencias de la Salud, University of Zaragoza, Zaragoza, Spain
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29
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Casa DJ, DeMartini JK, Bergeron MF, Csillan D, Eichner ER, Lopez RM, Ferrara MS, Miller KC, O'Connor F, Sawka MN, Yeargin SW. National Athletic Trainers' Association Position Statement: Exertional Heat Illnesses. J Athl Train 2015. [PMID: 26381473 DOI: 10.4085/1062-6050-50-9-07] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To present best-practice recommendations for the prevention, recognition, and treatment of exertional heat illnesses (EHIs) and to describe the relevant physiology of thermoregulation. BACKGROUND Certified athletic trainers recognize and treat athletes with EHIs, often in high-risk environments. Although the proper recognition and successful treatment strategies are well documented, EHIs continue to plague athletes, and exertional heat stroke remains one of the leading causes of sudden death during sport. The recommendations presented in this document provide athletic trainers and allied health providers with an integrated scientific and clinically applicable approach to the prevention, recognition, treatment of, and return-to-activity guidelines for EHIs. These recommendations are given so that proper recognition and treatment can be accomplished in order to maximize the safety and performance of athletes. RECOMMENDATIONS Athletic trainers and other allied health care professionals should use these recommendations to establish onsite emergency action plans for their venues and athletes. The primary goal of athlete safety is addressed through the appropriate prevention strategies, proper recognition tactics, and effective treatment plans for EHIs. Athletic trainers and other allied health care professionals must be properly educated and prepared to respond in an expedient manner to alleviate symptoms and minimize the morbidity and mortality associated with these illnesses.
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Affiliation(s)
| | | | | | | | - E Randy Eichner
- University of Oklahoma Health Sciences Center, Oklahoma City
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30
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Abstract
Exertional heat illness can be a serious consequence of sports or exercise in hot environments. Participants can possess intrinsic or face extrinsic risk factors that may increase their risk for heat-related illness. Knowledge of the physiology and pathology of heat illness, identification of risk factors, and strategies to combat heat accumulation will aid both the practitioner and the participant in preparing for activities that occur in hot environments. Through preparation and mitigation of risk, safe and enjoyable wilderness adventure can be pursued.
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31
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Adams WM, Ferraro EM, Huggins RA, Casa DJ. Influence of body mass loss on changes in heart rate during exercise in the heat: a systematic review. J Strength Cond Res 2015; 28:2380-9. [PMID: 24736771 DOI: 10.1519/jsc.0000000000000501] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this review was to compare the changes in heart rate (HR) for every 1% change in body mass loss (ΔBML) in individuals while exercising in the heat. PubMed, SPORTDiscus, ERIC, CINAHL, and Scopus were searched from the earliest entry to February 2013 using the search terms dehydration, heart rate, and exercise in various combinations. Original research articles that met the following criteria were included: (a) valid measure of HR, (b) exercise in the heat (>26.5° C [79.7 °F]), (c) the level of dehydration reached at least 2%, (d) a between-group comparison (a euhydrated group or a graded dehydration protocol) was evident, and (e) for rehydration protocols, only oral rehydration was considered for inclusion. Twenty articles were included in the final analysis. Mean values and SDs for HR and percentage of body mass loss immediately after exercise were used for this review. The mean change in HR for every 1% ΔBML was 3 b·min-1. In trials where subjects arrived euhydrated and hypohydrated, the mean change in HR for every 1% ΔBML was 3 and 3 b·min-1, respectively. Fixed intensity and variable intensity trials exhibited a mean HR change of 4 and 1 b·min-1, respectively. Exercising in the heat while hypohydrated (≥2%) resulted in an increased HR after exercise. This increase in HR for every 1% ΔBML exacerbates cardiovascular strain in exercising individuals, thus causing decrements in performance. It should be encouraged that individuals should maintain an adequate level of hydration to maximize performance, especially in the heat.
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Affiliation(s)
- William M Adams
- Korey Stringer Institute, Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, Connecticut
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32
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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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33
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Cheuvront SN, Kenefick RW. Dehydration: physiology, assessment, and performance effects. Compr Physiol 2014; 4:257-85. [PMID: 24692140 DOI: 10.1002/cphy.c130017] [Citation(s) in RCA: 260] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This article provides a comprehensive review of dehydration assessment and presents a unique evaluation of the dehydration and performance literature. The importance of osmolality and volume are emphasized when discussing the physiology, assessment, and performance effects of dehydration. The underappreciated physiologic distinction between a loss of hypo-osmotic body water (intracellular dehydration) and an iso-osmotic loss of body water (extracellular dehydration) is presented and argued as the single most essential aspect of dehydration assessment. The importance of diagnostic and biological variation analyses to dehydration assessment methods is reviewed and their use in gauging the true potential of any dehydration assessment method highlighted. The necessity for establishing proper baselines is discussed, as is the magnitude of dehydration required to elicit reliable and detectable osmotic or volume-mediated compensatory physiologic responses. The discussion of physiologic responses further helps inform and explain our analysis of the literature suggesting a ≥ 2% dehydration threshold for impaired endurance exercise performance mediated by volume loss. In contrast, no clear threshold or plausible mechanism(s) support the marginal, but potentially important, impairment in strength, and power observed with dehydration. Similarly, the potential for dehydration to impair cognition appears small and related primarily to distraction or discomfort. The impact of dehydration on any particular sport skill or task is therefore likely dependent upon the makeup of the task itself (e.g., endurance, strength, cognitive, and motor skill).
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Affiliation(s)
- Samuel N Cheuvront
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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34
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Stachenfeld NS. The interrelationship of research in the laboratory and the field to assess hydration status and determine mechanisms involved in water regulation during physical activity. Sports Med 2014; 44 Suppl 1:S97-104. [PMID: 24791921 PMCID: PMC4008811 DOI: 10.1007/s40279-014-0155-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Changes in skin blood and sweating are the primary mechanisms for heat loss in humans. A hot, humid environment concomitant with dehydration limits the ability to increase skin blood flow for the purpose of transferring heat from the body core to skin surface and evaporate sweat to maintain core temperature within safe limits during exercise. Adequate hydration improves thermoregulation by maintaining blood volume to support skin blood flow and sweating. Humans rely on fluid intake to maintain total body water and blood volume, and have developed complex mechanisms to sense changes in the amount and composition of fluid in the body. This paper addresses the interrelationship of research in the laboratory and the field to assess hydration status involved in body water and temperature regulation during exercise. In the controlled setting of a research laboratory, investigators are able to investigate the contributions of volume and tonicity of fluid in the plasma to body water and temperature regulation during exercise and recovery. For example, laboratory studies have shown that tonicity in a rehydration beverage maintains the thirst mechanism (and stimulates drinking), and contributes to the ongoing stimulation of renal fluid retention hormones, ultimately leading to a more complete rehydration. Research in the field cannot control the environment precisely, but these studies provide a natural, 'real-life' setting to study fluid and temperature regulation during exercise. The conditions encountered in the field are closest to the environment during competition, and data collected in the field can have an immediate impact on performance and safety during exercise. There is an important synergy between these two methods of collecting data that support performance and protect athletes from harm during training and improve performance during competition.
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Affiliation(s)
- Nina S Stachenfeld
- Departments of Obstetrics, Gynecology and Reproductive Sciences and Epidemiology and Public Health, The John B. Pierce Laboratory and Yale School of Medicine, 290 Congress Avenue, New Haven, CT, 06519, USA,
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Laitano O, Trangmar SJ, Marins DDM, Menezes ES, Reis GDS. Improved exercise capacity in the heat followed by coconut water consumption. MOTRIZ: REVISTA DE EDUCACAO FISICA 2014. [DOI: 10.1590/s1980-65742014000100016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to assess the effects of prior ingestion of coconut water on fluid retention and exercise capacity in the heat as well as signs of gastrointestinal distress. Eight physically active men were recruited (age 23 ± 3 years, height 176 ± 6 cm, body mass 78 ± 7 kg) and performed three exercise capacity trials on a cycle ergometer in the heat (34 ± 1°C) after the ingestion of one of the following drinks: a) plain water (PW), b) flavored drink (FD), and c) coconut water (CW). Ingestion of CWresulted in a longer time to exhaustion (p=0.029). Likewise, participants achieved a higher heart rate in the CW session when compared to the other trials (PW 183 ± 5 bpm, FD 184 ± 8 bpm, and CW 189 ± 8 bpm, p<0.05) and a reduced urine output after the coconut water ingestion (PW 214 ± 85 ml, FD 267 ± 90 ml, and CW 161 ± 73 ml, p<0.05) indicating a higher fluid retention of coconut water in comparison to plain water and the flavored drink. These results demonstrate that previous ingestion of coconut water improves exercise capacity in the heat and provide a reduced urine output in comparison to plain water and flavored drink. Also there is no evidence for GI distress.
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36
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Fleming J, James LJ. Repeated familiarisation with hypohydration attenuates the performance decrement caused by hypohydration during treadmill running. Appl Physiol Nutr Metab 2014; 39:124-9. [DOI: 10.1139/apnm-2013-0044] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined the effect of repeated familiarisation to hypohydration on hypohydrated exercise performance. After familiarisation with the exercise protocol, 10 recreationally active males completed a euhydrated (EU-pre) and hypohydrated (HYPO-pre) trial, which involved a 45-min steady state run at 75% peak oxygen uptake (45SS) followed by a 5-km time trial (TT). Euhydration and hypohydration were induced by manipulating fluid intake in the 24-h pre-exercise and during the 45SS. Subjects then completed 4 habituation sessions that involved replication of the HYPO-pre trial, except they completed 60 min of running at 75% peak oxygen uptake and no TT. Subjects then replicated the euhydrated (EU-post) and hypohydrated (HYPO-post) trials. Body mass loss pre-TT was 0.2 (0.2)% (EU-pre), 2.4 (0.3)% (HYPO-pre), 0.1 (0.1)% (EU-post), and 2.4 (0.3)% (HYPO-post). TT performance was 5.8 (2.4)% slower during the HYPO-pre trial (1459 (250) s) than during the EU-pre trial (1381 (237) s) (p < 0.01), but only 1.2 (1.6)% slower during the HYPO-post trial (1381 (200) s) than during the EU-post trial (1366 (211) s) (p = 0.064). TT performance was not different between EU-pre and EU-post trials, but was 5.1 (2.3)% faster during the HYPO-post trial than the HYPO-pre trial (p < 0.01). Heart rate was greater during HYPO trials than EU trials (p < 0.001), whilst rating of perceived exertion (RPE) response was similar to TT time and was lower in the HYPO-post trial than the HYPO-pre trial (p < 0.01). In conclusion, hypohydration impaired 5-km running performance in subjects unfamiliar with the hypohydration protocol, but 4 familiarisation sessions designed to habituate subjects with the hypohydration protocol attenuated the performance decrement, seemingly via an attenuation of RPE during hypohydrated exercise.
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Affiliation(s)
- Joseph Fleming
- SHAPE Research Group, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Lewis J. James
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- SHAPE Research Group, School of Science and Technology, Nottingham Trent University, Nottingham, UK
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37
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Pryor RR, Casa DJ, Adams WM, Belval LN, DeMartini JK, Huggins RA, Stearns RL, Vandermark LW. Maximizing Athletic Performance in the Heat. Strength Cond J 2013. [DOI: 10.1519/ssc.0000000000000016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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38
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Knoth C, Knechtle B, Rüst CA, Rosemann T, Lepers R. Participation and performance trends in multistage ultramarathons-the 'Marathon des Sables' 2003-2012. EXTREME PHYSIOLOGY & MEDICINE 2012; 1:13. [PMID: 23849138 PMCID: PMC3710135 DOI: 10.1186/2046-7648-1-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/05/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND The purpose of this study was to investigate participation and performance changes in the multistage ultramarathon 'Marathon des Sables' from 2003 to 2012. METHODS Participation and performance trends in the four- or six-stage running event covering approximately 250 km were analyzed with special emphasis on the nationality and age of the athletes. The relations between gender, age, and nationality of finishers and performance were investigated using regression analyses and analysis of variance. RESULTS Between 2003 and 2012, a number of 7,275 athletes with 938 women (12.9%) and 6,337 men (87.1%) finished the Marathon des Sables. The finisher rate in both women (r2 = 0.62) and men (r2 = 0.60) increased across years (p < 0.01). Men were significantly (p < 0.01) faster than women for overall finishers (5.9 ± 1.6 km·h-1 versus 5.1 ± 1.3 km·h-1) and for the top three finishers (12.2 ± 0.4 km·h-1 versus 8.3 ± 0.6 km·h-1). The gender difference in running speed of the top three athletes decreased (r2 = 0.72; p < 0.01) from 39.5% in 2003 to 24.1% in 2012 with a mean gender difference of 31.7 ± 2.0%. In men, Moroccans won nine of ten competitions, and one edition was won by a Jordanian athlete. In women, eight races were won by Europeans (France five, Luxembourg two, and Spain one, respectively), and two events were won by Moroccan runners. CONCLUSIONS The finisher rate in the Marathon des Sables increased this last decade. Men were significantly faster than women with a higher gender difference in performance compared to previous reports. Social or cultural inhibitions may determine the outcome in this event. Future studies need to investigate participation trends regarding nationalities and socioeconomic background, as well as the motivation to compete in ultramarathons.
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Affiliation(s)
- Christoph Knoth
- Department of Orthopaedics and Traumatology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Beat Knechtle
- Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland
- Gesundheitszentrum St. Gallen, Vadianstrasse 26, St. Gallen 9001, Switzerland
| | - Christoph Alexander Rüst
- Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland
| | - Thomas Rosemann
- Institute of General Practice and for Health Services Research, University of Zurich, Zurich, Switzerland
| | - Romuald Lepers
- INSERM U1093, Faculty of Sport Sciences, University of Burgundy, Dijon, France
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Knechtle B, Baumgartner S, Knechtle P, Rüst CA, Rosemann T, Bescós R. Changes in single skinfold thickness in 100 km ultramarathoners. Open Access J Sports Med 2012; 3:147-57. [PMID: 24198597 PMCID: PMC3781909 DOI: 10.2147/oajsm.s37035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Changes in single skinfold thickness and body fat have been investigated in ultraswimmers and ultracyclists, but not in ultrarunners. The present study investigated the changes in single skinfold thickness during a 100 km ultramarathon. Methods Firstly, we investigated associations between prerace preparation and prerace body composition and, secondly, changes in single skinfold thickness during a 100 km ultramarathon in 219 male ultramarathoners. Changes in fat mass and skeletal muscle were estimated using anthropometric methods. Results Kilometers run weekly prerace and running speed during training were negatively associated with all skinfold thicknesses (P < 0.05) except for the front thigh skinfold. During the race, skinfold thickness at the pectoral (−0.1%), suprailiac (−1.8%), and calf (−0.8%) sites decreased (P < 0.05). The subjects lost 1.9 ± 1.4 kg of body mass (P < 0.001), 0.7 ± 1.0 kg of estimated skeletal muscle mass (P < 0.001), and 0.2 ± 1.3 kg of estimated fat mass (P < 0.05). The decrease in body mass was positively related to the decrease in both estimated skeletal muscle mass (r = 0.21, P = 0.0017) and estimated fat mass (r = 0.41, P < 0.0001). Conclusion Firstly, prerace fat mass and prerace skinfold thickness were associated with both volume and speed in running training. Secondly, during the ultramarathon, skinfold thickness decreased at the pectoral, suprailiac, and calf sites, but not at the thigh site. Percent decreases in skinfold thickness for ultrarunners was lower than the percent decreases in skinfold thickness reported for ultraswimmers and ultracyclists.
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Affiliation(s)
- Beat Knechtle
- Institute of General Practice and Health Services Research, University of Zurich, Zurich; ; Gesundheitszentrum St Gallen, St Gallen, Switzerland
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Abstract
Little is known about the impact of habitual fluid intake on physiology. Specifically, biomarkers of hydration status and body water regulation have not been adequately explored in adults who consume different fluid volumes in everyday conditions, without prolonged exercise or environmental exposure. The purpose of the present study was to compare adults with habitually different fluid intakes with respect to biomarkers implicated in the assessment of hydration status, the regulation of total body water and the risk of kidney pathologies. In the present cross-sectional study, seventy-one adults (thirty-two men, thirty-nine women, age 25–40 years) were classified according to daily fluid intake: thirty-nine low drinkers (LD; ≤ 1·2 litres/d) and thirty-two high drinkers (HD; 2–4 litres/d). During four consecutive days, urinary parameters (first morning urine (FMU) on day 1 and subsequent 24 h urine (24hU) collections), blood parameters, and food and beverage intake were assessed. ANOVA and non-parametric comparisons revealed significant differences between the LD and HD groups in 24hU volume (1·0 (se 0·1) v. 2·4 (se 0·1) litres), specific gravity (median 1·023 v. 1·010), osmolality (767 (se 27) v. 371 (se 33) mOsm/kg) and colour (3·1 (se 0·2) v. 1·8 (se 0·2)). Similarly, in the FMU, the LD group produced a smaller amount of more concentrated urine. Plasma cortisol, creatinine and arginine vasopressin concentrations were significantly higher among the LD. Plasma osmolality was similar between the groups, suggesting physiological adaptations to preserve plasma osmolality despite low fluid intake. The long-term impact of adaptations to preserve plasma osmolality must be examined, particularly in the context of renal health.
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Kalman DS, Feldman S, Krieger DR, Bloomer RJ. Comparison of coconut water and a carbohydrate-electrolyte sport drink on measures of hydration and physical performance in exercise-trained men. J Int Soc Sports Nutr 2012; 9:1. [PMID: 22257640 PMCID: PMC3293068 DOI: 10.1186/1550-2783-9-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 01/18/2012] [Indexed: 11/10/2022] Open
Abstract
Background Sport drinks are ubiquitous within the recreational and competitive fitness and sporting world. Most are manufactured and artificially flavored carbohydrate-electrolyte beverages. Recently, attention has been given to coconut water, a natural alternative to manufactured sport drinks, with initial evidence indicating efficacy with regard to maintaining hydration. We compared coconut water and a carbohydrate-electrolyte sport drink on measures of hydration and physical performance in exercise-trained men. Methods Following a 60-minute bout of dehydrating treadmill exercise, 12 exercise-trained men (26.6 ± 5.7 yrs) received bottled water (BW), pure coconut water (VitaCoco®: CW), coconut water from concentrate (CWC), or a carbohydrate-electrolyte sport drink (SD) [a fluid amount based on body mass loss during the dehydrating exercise] on four occasions (separated by at least 5 days) in a random order, single blind (subject and not investigators), cross-over design. Hydration status (body mass, fluid retention, plasma osmolality, urine specific gravity) and performance (treadmill time to exhaustion; assessed after rehydration) were determined during the recovery period. Subjective measures of thirst, bloatedness, refreshed, stomach upset, and tiredness were also determined using a 5-point visual analog scale. Results Subjects lost approximately 1.7 kg (~2% of body mass) during the dehydrating exercise and regained this amount in a relatively similar manner following consumption of all conditions. No differences were noted between coconut water (CW or CWC) and SD for any measures of fluid retention (p > 0.05). Regarding exercise performance, no significant difference (p > 0.05) was noted between BW (11.9 ± 5.9 min), CW (12.3 ± 5.8 min), CWC (11.9 ± 6.0 min), and SD (12.8 ± 4.9 min). In general, subjects reported feeling more bloated and experienced greater stomach upset with the CW and CWC conditions. Conclusion All tested beverages are capable of promoting rehydration and supporting subsequent exercise. Little difference is noted between the four tested conditions with regard to markers of hydration or exercise performance in a sample of young, healthy men. Additional study inclusive of a more demanding dehydration protocol, as well as a time trial test as the measure of exercise performance, may more specifically determine the efficacy of these beverages on enhancing hydration and performance following dehydrating exercise.
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Affiliation(s)
- Douglas S Kalman
- The University of Memphis, Cardiorespiratory/Metabolic Laboratory, Department of Health and Sport Sciences, 106 Roane Fieldhouse, Memphis, TN 38152.
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