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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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Moore SR, Gordon AN, Cabre HE, Hackney AC, Smith-Ryan AE. A Randomized Controlled Trial of Changes in Fluid Distribution across Menstrual Phases with Creatine Supplementation. Nutrients 2023; 15:nu15020429. [PMID: 36678300 PMCID: PMC9865497 DOI: 10.3390/nu15020429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
This study examined the effects of creatine (Cr) loading on body mass (BM) and fluid markers of total body water (TBW), extra-cellular fluid (ECF), and intra-cellular fluid (ICF) across the menstrual cycle (MC). Thirty moderately active females, either naturally-menstruating (NM) or using hormonal contraceptives (HC), were randomized to Cr (Cr; 4 × 5 g/day of creatine monohydrate for 5 days; n = 15) or a non-caloric placebo (PL; n = 15) using a double-blind, placebo-controlled design, with a menstrual phase crossover. BM, TBW, ECF, and ICF were measured at pre- and post-supplementation in randomized order of follicular phase (FP; NM: MC days 0−8, HC: inactive pill days) or luteal phase (LP; NM: ≤15 days from next projected cycle start date, HC: active pill days) using bioelectrical impedance spectroscopy. Acute hydration status and salivary estrogen were used as covariates. Change in BM was not different between groups across MC ([PL-Cr] Δ 0.40 ± 0.50 kg; p = 0.427) or between MC phase across groups ([FP-LP] Δ 0.31 ± 0.48 kg; p = 0.528). TBW (p = 0.802), ECF (p = 0.373), and ICF (p = 0.795) were not different between supplement groups at pre-supplementation/FP time points. There were no significant differences between the NM and HC subjects at any time point, for any outcome (p > 0.05). Following LP supplementation, significant changes were observed in TBW (Cr: Δ 0.83 ± 0.38 L, PL: Δ −0.62 ± 0.38 L; p = 0.021), ECF (Cr: Δ 0.46 ± 0.15 L, PL: Δ −0.19 ± 0.15 L; p = 0.013), and ICF (Cr: Δ 0.74 ± 0.23 L, PL: Δ −0.02 ± 0.23 L; p = 0.041). These data demonstrate an increase in all fluid compartments in the LP following Cr loading, without observed alterations in body weight for females.
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Affiliation(s)
- Sam R. Moore
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Human Movement Science Curriculum, Department of Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Amanda N. Gordon
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Hannah E. Cabre
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Human Movement Science Curriculum, Department of Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Anthony C. Hackney
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Abbie E. Smith-Ryan
- Applied Physiology Laboratory, Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Human Movement Science Curriculum, Department of Health Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
- Correspondence: ; Tel.: +1-919-962-2574
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Gonzalez DE, McAllister MJ, Waldman HS, Ferrando AA, Joyce J, Barringer ND, Dawes JJ, Kieffer AJ, Harvey T, Kerksick CM, Stout JR, Ziegenfuss TN, Zapp A, Tartar JL, Heileson JL, VanDusseldorp TA, Kalman DS, Campbell BI, Antonio J, Kreider RB. International society of sports nutrition position stand: tactical athlete nutrition. J Int Soc Sports Nutr 2022; 19:267-315. [PMID: 35813846 PMCID: PMC9261739 DOI: 10.1080/15502783.2022.2086017] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Drew E. Gonzalez
- Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Department of Health & Kinesiology Texas A&M University, College Station, TX, USA
| | - Matthew J. McAllister
- Texas State University, Metabolic and Applied Physiology Laboratory, Department of Health & Human Performance, San Marcos, TX, USA
| | - Hunter S. Waldman
- University of North Alabama, Department of Kinesiology, Florence, AL, USA
| | - Arny A. Ferrando
- University of Arkansas for Medical Sciences, Department of Geriatrics, Little Rock, AR, USA
| | - Jill Joyce
- Oklahoma State University, Department of Nutritional Sciences, Stillwater, OK, USA
| | - Nicholas D. Barringer
- US. Army-Baylor Master’s Program in Nutrition, Department of Nutrition, San Antonio, TX, USA
| | - J. Jay Dawes
- Oklahoma State University, Department of Kinesiology, Applied Health, and Recreation, Stillwater, OK, USA
| | - Adam J. Kieffer
- Brooke Army Medical Center, Department of Nutritional Medicine, San Antonio, TX, USA
| | - Travis Harvey
- United States Special Operations Command, Preservation of the Force and Family, Tampa, FL, USA
| | - Chad M. Kerksick
- Lindenwood University, Exercise and Performance Nutrition Laboratory, College of Science, Technology, and Health, St. Charles, MO, USA
| | - Jeffrey R. Stout
- University of Central Florida, Institute of Exercise Physiology and Rehabilitation Sciences, School of Kinesiology and Physical Therapy, Orlando, FL, USA
| | | | | | - Jamie L. Tartar
- Nova Southeastern University, Department of Psychology and Neuroscience, Fort Lauderdale, FL, USA
| | - Jeffery L. Heileson
- Baylor University, Department of Health, Human Performance, and Recreation, Waco, TX, USA
| | | | - Douglas S. Kalman
- Dr. Kiran C Patel College of Osteopathic Medicine, Nova Southeastern University, Nutrition Department, Davie, FL, USA
| | - Bill I. Campbell
- University of South Florida, Performance & Physique Enhancement Laboratory, Exercise Science Program, Tampa, FL, USA
| | - Jose Antonio
- Fight Science Laboratory, Nova Southeastern University, Department of Health and Human Performance, Davie, FL, USA
| | - Richard B. Kreider
- Exercise & Sport Nutrition Laboratory, Human Clinical Research Facility, Department of Health & Kinesiology Texas A&M University, College Station, TX, USA
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Peel JS, McNarry MA, Heffernan SM, Nevola VR, Kilduff LP, Waldron M. The Effect of Dietary Supplements on Endurance Exercise Performance and Core Temperature in Hot Environments: A Meta-analysis and Meta-regression. Sports Med 2021; 51:2351-2371. [PMID: 34129223 PMCID: PMC8514372 DOI: 10.1007/s40279-021-01500-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND The ergogenic effects of dietary supplements on endurance exercise performance are well-established; however, their efficacy in hot environmental conditions has not been systematically evaluated. OBJECTIVES (1) To meta-analyse studies investigating the effects of selected dietary supplements on endurance performance and core temperature responses in the heat. Supplements were included if they were deemed to: (a) have a strong evidence base for 'directly' improving thermoneutral endurance performance, based on current position statements, or (b) have a proposed mechanism of action that related to modifiable factors associated with thermal balance. (2) To conduct meta-regressions to evaluate the moderating effect of selected variables on endurance performance and core temperature responses in the heat following dietary supplementation. METHODS A search was performed using various databases in May 2020. After screening, 25 peer-reviewed articles were identified for inclusion, across three separate meta-analyses: (1) exercise performance; (2) end core temperature; (3) submaximal core temperature. The moderating effect of several variables were assessed via sub-analysis and meta-regression. RESULTS Overall, dietary supplementation had a trivial significant positive effect on exercise performance (Hedges' g = 0.18, 95% CI 0.007-0.352, P = 0.042), a trivial non-significant positive effect on submaximal core temperature (Hedges' g = 0.18, 95% CI - 0.021 to 0.379, P = 0.080) and a small non-significant positive effect on end core temperature (Hedges' g = 0.20, 95% CI - 0.041 to 0.439, P = 0.104) in the heat. There was a non-significant effect of individual supplements on exercise performance (P = 0.973) and submaximal core temperature (P = 0.599). However, end core temperature was significantly affected by supplement type (P = 0.003), which was attributable to caffeine's large significant positive effect (n = 8; Hedges' g = 0.82, 95% CI 0.433-1.202, P < 0.001) and taurine's medium significant negative effect (n = 1; Hedges' g = - 0.96, 95% CI - 1.855 to - 0.069, P = 0.035). CONCLUSION Supplements such as caffeine and nitrates do not enhance endurance performance in the heat, with caffeine also increasing core temperature responses. Some amino acids might offer the greatest performance benefits in the heat. Exercising in the heat negatively affected the efficacy of many dietary supplements, indicating that further research is needed and current guidelines for performance in hot environments likely require revision.
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Affiliation(s)
- Jennifer S Peel
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK.
| | - Melitta A McNarry
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
| | - Shane M Heffernan
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
| | - Venturino R Nevola
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
- Defence Science and Technology Laboratory (Dstl), Fareham, Hampshire, UK
| | - Liam P Kilduff
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
| | - Mark Waldron
- A-STEM Centre, College of Engineering, Swansea University, Swansea, UK
- Welsh Institute of Performance Science, Swansea University, Swansea, UK
- School of Science and Technology, University of New England, Armidale, NSW, Australia
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5
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Périard JD, Eijsvogels TMH, Daanen HAM. Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies. Physiol Rev 2021; 101:1873-1979. [PMID: 33829868 DOI: 10.1152/physrev.00038.2020] [Citation(s) in RCA: 127] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.
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Affiliation(s)
- Julien D Périard
- University of Canberra Research Institute for Sport and Exercise, Bruce, Australia
| | - Thijs M H Eijsvogels
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hein A M Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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Antonio J, Candow DG, Forbes SC, Gualano B, Jagim AR, Kreider RB, Rawson ES, Smith-Ryan AE, VanDusseldorp TA, Willoughby DS, Ziegenfuss TN. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr 2021; 18:13. [PMID: 33557850 PMCID: PMC7871530 DOI: 10.1186/s12970-021-00412-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/28/2021] [Indexed: 01/01/2023] Open
Abstract
Supplementing with creatine is very popular amongst athletes and exercising individuals for improving muscle mass, performance and recovery. Accumulating evidence also suggests that creatine supplementation produces a variety of beneficial effects in older and patient populations. Furthermore, evidence-based research shows that creatine supplementation is relatively well tolerated, especially at recommended dosages (i.e. 3-5 g/day or 0.1 g/kg of body mass/day). Although there are over 500 peer-refereed publications involving creatine supplementation, it is somewhat surprising that questions regarding the efficacy and safety of creatine still remain. These include, but are not limited to: 1. Does creatine lead to water retention? 2. Is creatine an anabolic steroid? 3. Does creatine cause kidney damage/renal dysfunction? 4. Does creatine cause hair loss / baldness? 5. Does creatine lead to dehydration and muscle cramping? 6. Is creatine harmful for children and adolescents? 7. Does creatine increase fat mass? 8. Is a creatine 'loading-phase' required? 9. Is creatine beneficial for older adults? 10. Is creatine only useful for resistance / power type activities? 11. Is creatine only effective for males? 12. Are other forms of creatine similar or superior to monohydrate and is creatine stable in solutions/beverages? To answer these questions, an internationally renowned team of research experts was formed to perform an evidence-based scientific evaluation of the literature regarding creatine supplementation.
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Affiliation(s)
- Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, Florida, USA.
| | - Darren G Candow
- Faculty of Kinesiology and Health Studies, University of Regina, Regina, Canada
| | - Scott C Forbes
- Department of Physical Education, Faculty of Education, Brandon University, Brandon, MB, Canada
| | - Bruno Gualano
- Applied Physiology & Nutrition Research Group; School of Medicine, FMUSP, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Andrew R Jagim
- Sports Medicine Department, Mayo Clinic Health System, La Crosse, WI, USA
| | - Richard B Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, USA
| | - Eric S Rawson
- Department of Health, Nutrition, and Exercise Science, Messiah University, Mechanicsburg, PA, USA
| | - Abbie E Smith-Ryan
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, USA
| | - Trisha A VanDusseldorp
- Department of Exercise Science and Sport Management, Kennesaw State University, Kennesaw, GA, USA
| | - Darryn S Willoughby
- School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
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7
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Detecting creatine excreted in the urine of swimming athletes by means of Raman spectroscopy. Lasers Med Sci 2019; 35:455-464. [DOI: 10.1007/s10103-019-02843-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 07/08/2019] [Indexed: 01/09/2023]
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8
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Machek SB, Bagley JR. Creatine Monohydrate Supplementation: Considerations for Cognitive Performance in Athletes. Strength Cond J 2018. [DOI: 10.1519/ssc.0000000000000369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Nutrition and Supplementation Considerations to Limit Endotoxemia When Exercising in the Heat. Sports (Basel) 2018; 6:sports6010012. [PMID: 29910316 PMCID: PMC5969196 DOI: 10.3390/sports6010012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/25/2018] [Accepted: 01/31/2018] [Indexed: 02/07/2023] Open
Abstract
Exercise-induced heat production is further elevated by exercise performed in hot conditions and this can subsequently impact inflammation, and gastrointestinal (GI) health. Implementing nutrition and supplementation strategies under these conditions may support the hyperthermic response, the systemic inflammatory response, GI permeability and integrity, and exercise performance. Therefore, the aim of this brief review is to explore athletes' inflammatory response of two key biomarkers, lipopolysaccharide (LPS), and interleukin-6 (IL-6), and provide nutrition and supplementation recommendations when exercising in hot conditions. There is emerging evidence that probiotics, glutamine, and vitamin C can preserve GI integrity, which may improve performance during exercise in the heat. Glucose rich food when consumed with water, before and during exercise in the heat, also appear to limit endotoxemia, preserve GI integrity, and reduce the incidence of GI disturbances compared with water alone. The use of non-steroidal anti-inflammatory drugs (NSAIDs) may compromise GI integrity and this may result in greater leakage of endotoxins during long duration exercise in the heat. Further work is required to elucidate the impact of nutrition and supplementation strategies, in particular the use of NSAIDs, when exercising in the heat.
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Kreider RB, Kalman DS, Antonio J, Ziegenfuss TN, Wildman R, Collins R, Candow DG, Kleiner SM, Almada AL, Lopez HL. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr 2017; 14:18. [PMID: 28615996 PMCID: PMC5469049 DOI: 10.1186/s12970-017-0173-z] [Citation(s) in RCA: 303] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 05/30/2017] [Indexed: 12/16/2022] Open
Abstract
Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).
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Affiliation(s)
- Richard B. Kreider
- Exercise & Sport Nutrition Lab, Human Clinical Research Facility, Department of Health & Kinesiology, Texas A&M University, College Station, TX 77843-4243 USA
| | - Douglas S. Kalman
- Nutrition Research Unit, QPS, 6141 Sunset Drive Suite 301, Miami, FL 33143 USA
| | - Jose Antonio
- Department of Health and Human Performance, Nova Southeastern University, Davie, FL 33328 USA
| | - Tim N. Ziegenfuss
- The Center for Applied Health Sciences, 4302 Allen Road, STE 120, Stow, OH 44224 USA
| | - Robert Wildman
- Post Active Nutrition, 111 Leslie St, Dallas, TX 75208 USA
| | - Rick Collins
- Collins Gann McCloskey & Barry, PLLC, 138 Mineola Blvd., Mineola, NY 11501 USA
| | - Darren G. Candow
- Faculty of Kinesiology and Health Studies, University of Regina, Regina, SK S4S 0A2 Canada
| | | | | | - Hector L. Lopez
- The Center for Applied Health Sciences, 4302 Allen Road, STE 120, Stow, OH 44224 USA
- Supplement Safety Solutions, LLC, Bedford, MA 01730 USA
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11
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Short-term creatine supplementation has no impact on upper-body anaerobic power in trained wrestlers. J Int Soc Sports Nutr 2015; 12:45. [PMID: 26664350 PMCID: PMC4673838 DOI: 10.1186/s12970-015-0107-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 12/04/2015] [Indexed: 11/25/2022] Open
Abstract
Background Creatine (CR) is considered an effective nutritional supplement having ergogenic effects, which appears more pronounced in upper-body compared to lower-body exercise. Nevertheless, results regarding the impact of CR loading on repeated high-intensity arm-cranking exercise are scarce and in some cases conflicting. Interestingly, few of the conducted studies have structured their research designs to mimic real world sporting events. Therefore, our purpose was to address the hypothesis that CR ingestion would increase anaerobic power output in consecutive upper-body intermittent sprint performance (UBISP) tests designed to simulate wrestling matches on a competition-day. Methods In a double-blind, placebo-controlled, parallel-group study, 20 trained wrestlers were assigned to either placebo or CR supplemented group (0.3 g ∙ kg−1 of body mass per day). Four 6-min UBISP tests interspersed with 30-min recovery periods were performed before (trial 1) and after 5 days (trial 2) of supplementation. Each test consisted of six 15-s periods of arm-cranking at maximal executable cadence against resistance of 0.04 kg ∙ kg−1 body mass interspersed with 40-s unloaded easy cranking periods and 5-s acceleration intervals (T1–T4). Mean power (MP), peak power (PP), fatigue index and heart rate parameters were measured during UBISP tests. Also, body weight and hydration status were assessed. Principle measures were statistical analysed with mixed-model ANOVAs. Results Mean individual CR consumption in the CR group was 24.8 ± 2.5 g ∙ d−1. No significant (P > 0.05) differences occurred in body mass or hydration status indices between the groups or across trials. MP, PP and fatigue index responses were unaffected by supplementation; although, a significant reduction in MP and PP did occurred from T1 to T4 in both trial 1 and 2 (P < 0.001). Overall heart rate responses in the tests tended to be higher in the CR than PLC group (P < 0.05); but, trends in responses in trials and tests were comparable (P > 0.05). Conclusion These results suggest that 5-day CR supplementation has no impact on upper-body muscle anaerobic power output in consecutive UBISP anaerobic tests mimicking wrestling matches on a competition day.
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12
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Havenetidis K. The use of creatine supplements in the military. J ROY ARMY MED CORPS 2015; 162:242-8. [DOI: 10.1136/jramc-2014-000400] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/08/2015] [Indexed: 01/06/2023]
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13
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Zanelli JCS, Cordeiro BA, Beserra BTS, Trindade EBSDM. Creatina e treinamento resistido: efeito na hidratação e massa corporal magra. REV BRAS MED ESPORTE 2015. [DOI: 10.1590/1517-86922015210101932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUÇÃO: a creatina é um recurso ergogênico cuja suplementação tem sido associada ao aumento da hidratação corporal total e ao aumento da massa muscular dos consumidores. Entretanto, estudiosos questionam se o aumento da massa muscular é um ganho real.OBJETIVO: avaliar o efeito da suplementação de creatina sobre a hidratação e o aumento de massa magra em indivíduos previamente treinados e não treinados, submetidos a um programa de treinamento resistido.MÉTODOS: ensaio clínico não randomizado, constituído por três momentos, M1 - Início da suplementação com 20g/dia de creatina; M2 - 7 dias após iniciada a suplementação e redução da suplementação para 5g/dia; M3 - 28 dias de suplementação. Nos momentos propostos, foram realizadas aferições de peso, estatura e avaliação da composição corporal (massa magra, água corporal total) com a utilização do BYODINAMICS(r) Modelo 310. Para todos os testes estatísticos, foi adotado o nível de significância de 95% (p<0,05).RESULTADOS: participaram desse estudo 14 voluntários adultos do sexo masculino, com idade média de 22,57(±1,45) anos, dos quais sete eram treinados e sete não treinados. Após 28 dias de suplementação, no grupo treinado observou-se um aumento significativo no peso, água corporal total, massa magra e hidratação da massa magra, mas nenhum aumento significativo foi observado no grupo não treinado. Em relação ao ângulo de fase, este aumentou no grupo não treinado e reduziu no grupo treinado.CONCLUSÃO: a suplementação de creatina associada ao treinamento resistido é mais efetiva na hidratação de indivíduos treinados, como também é suficiente para reduzir a diferença significativa do ângulo de fase intergrupos, sugerindo assim, maior hidratação celular em ambos os grupos. Contudo, esse aumento na hidratação não revelou aumento significativo no tecido muscular.
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Effects of glycerol and creatine hyperhydration on doping-relevant blood parameters. Nutrients 2012; 4:1171-86. [PMID: 23112907 PMCID: PMC3475229 DOI: 10.3390/nu4091171] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 07/17/2012] [Accepted: 08/16/2012] [Indexed: 12/04/2022] Open
Abstract
Glycerol is prohibited as an ergogenic aid by the World Anti-Doping Agency (WADA) due to the potential for its plasma expansion properties to have masking effects. However, the scientific basis of the inclusion of Gly as a “masking agent” remains inconclusive. The purpose of this study was to determine the effects of a hyperhydrating supplement containing Gly on doping-relevant blood parameters. Nine trained males ingested a hyperhydrating mixture twice per day for 7 days containing 1.0 g·kg−1 body mass (BM) of Gly, 10.0 g of creatine and 75.0 g of glucose. Blood samples were collected and total hemoglobin (Hb) mass determined using the optimized carbon monoxide (CO) rebreathing method pre- and post-supplementation. BM and total body water (TBW) increased significantly following supplementation by 1.1 ± 1.2 and 1.0 ± 1.2 L (BM, P < 0.01; TBW, P <0.01), respectively. This hyperhydration did not significantly alter plasma volume or any of the doping-relevant blood parameters (e.g., hematocrit, Hb, reticulocytes and total Hb-mass) even when Gly was clearly detectable in urine samples. In conclusion, this study shows that supplementation with hyperhydrating solution containing Gly for 7 days does not significantly alter doping-relevant blood parameters.
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Polyviou TP, Pitsiladis YP, Lee WC, Pantazis T, Hambly C, Speakman JR, Malkova D. Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists. J Int Soc Sports Nutr 2012; 9:29. [PMID: 22726625 PMCID: PMC3459729 DOI: 10.1186/1550-2783-9-29] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 06/13/2012] [Indexed: 11/25/2022] Open
Abstract
Background It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat. Purpose To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala). Methods 22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g .kg-1 BM per day (4 × 0.5 g .kg-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O2 max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity. Results Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (P = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (P = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups. Conclusions In comparison to the established hyper hydrating Cr/Gly/Glu supplement, supplement containing Cr/Gly/Ala and decreased amount of Glu provides equal improvements in thermoregulatory and cardiovascular responses during exercise in the heat.
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Affiliation(s)
- Thelma P Polyviou
- Medical School, College of Medicine, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
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Beis LY, Polyviou T, Malkova D, Pitsiladis YP. The effects of creatine and glycerol hyperhydration on running economy in well trained endurance runners. J Int Soc Sports Nutr 2011; 8:24. [PMID: 22176668 PMCID: PMC3283512 DOI: 10.1186/1550-2783-8-24] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/16/2011] [Indexed: 11/16/2022] Open
Abstract
Background Ingestion of creatine (Cr) and glycerol (Gly) has been reported to be an effective method in expanding water compartments within the human body, attenuating the rise in heart rate (HR) and core temperature (Tcore) during exercise in the heat. Despite these positive effects, a substantial water retention could potentially impair endurance performance through increasing body mass (BM) and consequently impacting negatively on running economy (RE). The objective of the present study was to investigate the effects of a combined Cr and Gly supplementation on thermoregulatory and cardiovascular responses and RE during running for 30 min at speed corresponding to 60% of maximal oxygen uptake (V˙O2max) in hot and cool conditions. Methods Cr·H2O (11.4 g), Gly (1 g·kg-1 BM) and Glucose polymer (75 g) were administered twice daily to 15 male endurance runners during a 7-day period. Exercise trials were conducted pre- and post-supplementation at 10 and 35°C and 70% relative humidity. Results BM and total body water increased by 0.90 ± 0.40 kg (P < 0.01; mean ± SD) and 0.71 ± 0.42 L (P < 0.01), respectively following supplementation. Despite the significant increase in BM, supplementation had no effect on V˙O2 and therefore RE. Both HR and Tcore were attenuated significantly after supplementation (P < 0.05, for both). Nevertheless, thermal comfort and rating of perceived exertion was not significantly different between pre- and post-supplementation. Similarly, no significant differences were found in sweat loss, serum osmolality, blood lactate and in plasma volume changes between pre- and post-supplementation. Conclusions Combining Cr and Gly is effective in reducing thermal and cardiovascular strain during exercise in the heat without negatively impacting on RE.
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Affiliation(s)
- Lukas Y Beis
- College of Medicine, Veterinary and Life Sciences, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
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Sheikholeslami Vatani D, Faraji H, Soori R, Mogharnasi M. The effects of creatine supplementation on performance and hormonal response in amateur swimmers. Sci Sports 2011. [DOI: 10.1016/j.scispo.2011.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Sobolewski EJ, Thompson BJ, Smith AE, Ryan ED. The Physiological Effects of Creatine Supplementation on Hydration: A Review. Am J Lifestyle Med 2011. [DOI: 10.1177/1559827611406071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In 1992, Harris and colleagues demonstrated that oral creatine supplementation can enhance muscle creatine stores. Since then, creatine has become an important and popular ergogenic aid for improving athletic performance with reports of up to 74% of athletes supplementing with creatine. Although many recent studies have addressed the safety concerns of creatine supplementation on hydration status in hot and humid environments, anecdotal reports still exist linking creatine usage to heat-related problems. These concerns are based on the premise that creatine is an osmotically active substance resulting in an alteration in fluid balance by increasing intracellular fluid volume and preventing fluid from entering the extracellular environment to aid in thermoregulation. However, a number studies have demonstrated that when recommended amounts of creatine are consumed, creatine does not appear to increase the risk of heat-related problems during exercise and may actually have a positive influence on core temperature and heart rate responses.
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Affiliation(s)
- Eric J. Sobolewski
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
| | - Brennan J. Thompson
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
| | - Abbie E. Smith
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,
| | - Eric D. Ryan
- Department of Health and Human Performance, Oklahoma State University, Stillwater, Oklahoma
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Kingsley M, Cunningham D, Mason L, Kilduff LP, McEneny J. Role of creatine supplementation on exercise-induced cardiovascular function and oxidative stress. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2011; 2:247-54. [PMID: 20716911 PMCID: PMC2763263 DOI: 10.4161/oxim.2.4.9415] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many degenerative diseases are associated with increased oxidative stress. Creatine has the potential to act as an indirect and direct antioxidant; however, limited data exist to evaluate the antioxidant capabilities of creatine supplementation within in vivo human systems. This study aimed to investigate the effects of oral creatine supplementation on markers of oxidative stress and antioxidant defenses following exhaustive cycling exercise. Following preliminary testing and two additional familiarization sessions, 18 active males repeated two exhaustive incremental cycling trials (T1 and T2) separated by exactly 7 days. The subjects were assigned, in a double-blind manner, to receive either 20 g of creatine (Cr) or a placebo (P) for the 5 days preceding T2. Breath-by-breath respiratory data and heart rate were continually recorded throughout the exercise protocol and blood samples were obtained at rest (preexercise), at the end of exercise (postexercise), and the day following exercise (post24 h). Serum hypdroperoxide concentrations were elevated at postexercise by 17 ± 5% above preexercise values (p = 0.030). However, supplementation did not influence lipid peroxidation (serum hypdroperoxide concentrations), resistance of low density lipoprotein to oxidative stress (t1/2max LDL oxidation) and plasma concentrations of non-enzymatic antioxidants (retinol, α-carotene, β-carotene, α-tocopherol, γ-tocopherol, lycopene and vitamin C). Heart rate and oxygen uptake responses to exercise were not affected by supplementation. These findings suggest that short-term creatine supplementation does not enhance non-enzymatic antioxidant defence or protect against lipid peroxidation induced by exhaustive cycling in healthy males.
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Lopez RM, Casa DJ, McDermott BP, Ganio MS, Armstrong LE, Maresh CM. Does creatine supplementation hinder exercise heat tolerance or hydration status? A systematic review with meta-analyses. J Athl Train 2009; 44:215-23. [PMID: 19295968 DOI: 10.4085/1062-6050-44.2.215] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To critically assess original research addressing the effect of creatine supplementation on exercise heat tolerance and hydration status. DATA SOURCES We searched the electronic databases PubMed, Scopus, Web of Science, SPORTDiscus, and Rehabilitation & Physical Medicine, without date limitations, for the following key words: creatine, exercise, thermoregulation, dehydration, hyperthermia, heat tolerance, exertional heat illnesses, and renal function. Our goal was to identify randomized clinical trials investigating the effect of creatine supplementation on hydration status and thermoregulation. Citations from related articles also were identified and retrieved. DATA SYNTHESIS Original research was reviewed using the Physiotherapy Evidence Database (PEDro) Scale. One author initially screened all articles. Fifteen of 95 articles examined the effects of creatine on thermoregulation or hydration status (or both). Two independent reviewers then reviewed these articles. Ten studies were selected on the basis of inclusion and exclusion criteria. The PEDro scores for the 10 studies ranged from 7 to 10 points (maximum possible score = 10 points). CONCLUSIONS No evidence supports the concept that creatine supplementation either hinders the body's ability to dissipate heat or negatively affects the athlete's body fluid balance. Controlled experimental trials of athletes exercising in the heat resulted in no adverse effects from creatine supplementation at recommended dosages.
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Easton C, Calder A, Prior F, Dobinson S, I’Anson R, MacGregor R, Mohammad Y, Kingsmore D, Pitsiladis YP. The effects of a novel “fluid loading” strategy on cardiovascular and haematological responses to orthostatic stress. Eur J Appl Physiol 2009; 105:899-908. [DOI: 10.1007/s00421-008-0976-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/23/2008] [Indexed: 11/25/2022]
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Hadjicharalambous M, Kilduff LP, Pitsiladis YP. Brain serotonin and dopamine modulators, perceptual responses and endurance performance during exercise in the heat following creatine supplementation. J Int Soc Sports Nutr 2008; 5:14. [PMID: 18826587 PMCID: PMC2570654 DOI: 10.1186/1550-2783-5-14] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 09/30/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The present experiment examined the responses of peripheral modulators and indices of brain serotonin (5-HT) and dopamine (DA) function and their association with perception of effort during prolonged exercise in the heat after creatine (Cr) supplementation. METHODS Twenty one endurance-trained males performed, in a double-blind fashion, two constant-load exercise tests to exhaustion at 63 +/- 5% V(O2) max in the heat (ambient temperature: 30.3 +/- 0.5 degrees C, relative humidity: 70 +/- 2%) before and after 7 days of Cr (20 g.d-1 Cr + 140 g.d-1 glucose polymer) or placebo (Plc) (160 g.d-1 glucose polymer) supplementation. RESULTS 3-way interaction has shown that Cr supplementation reduced rectal temperature, heart rate, ratings of perceived leg fatigue (P < 0.05), plasma free-tryptophan (Trp) (P < 0.01) and free-Trp:tyrosine ratio (P < 0.01) but did not influence the ratio of free-Trp:large neutral amino acids or contribute in improving endurance performance (Plc group, n = 10: 50.4 +/- 8.4 min vs. 51.2 +/- 8.0 min, P > 0.05; Cr group, n = 11: 47.0 +/- 4.7 min vs. 49.7 +/- 7.5 min, P > 0.05). However, after dividing the participants into "responders" and "non-responders" to Cr, based on their intramuscular Cr uptake, performance was higher in the "responders" relative to "non-responders" group (51.7 +/- 7.4 min vs.47.3 +/- 4.9 min, p < 0.05). CONCLUSION Although Cr influenced key modulators of brain 5-HT and DA function and reduced various thermophysiological parameters which all may have contributed to the reduced effort perception during exercise in the heat, performance was improved only in the "responders" to Cr supplementation. The present results may also suggest the demanding of the pre-experimental identification of the participants into "responders" and "non-responders" to Cr supplementation before performing the main experimentation. Otherwise, the possibility of the type II error may be enhanced.
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Gotshalk LA, Kraemer WJ, Mendonca MAG, Vingren JL, Kenny AM, Spiering BA, Hatfield DL, Fragala MS, Volek JS. Creatine supplementation improves muscular performance in older women. Eur J Appl Physiol 2007; 102:223-31. [DOI: 10.1007/s00421-007-0580-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2007] [Indexed: 01/06/2023]
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Buford TW, Kreider RB, Stout JR, Greenwood M, Campbell B, Spano M, Ziegenfuss T, Lopez H, Landis J, Antonio J. International Society of Sports Nutrition position stand: creatine supplementation and exercise. J Int Soc Sports Nutr 2007; 4:6. [PMID: 17908288 PMCID: PMC2048496 DOI: 10.1186/1550-2783-4-6] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2007] [Accepted: 08/30/2007] [Indexed: 11/10/2022] Open
Affiliation(s)
- Thomas W Buford
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Richard B Kreider
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Jeffrey R Stout
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Mike Greenwood
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Bill Campbell
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Marie Spano
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Tim Ziegenfuss
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Hector Lopez
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Jamie Landis
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
| | - Jose Antonio
- International Society of Sports Nutrition, 600 Pembrook Drive, Woodland Park, CO 80863, USA
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Abstract
The literature on creatine supplementation supporting its efficacy has grown rapidly and has included studies in both healthy volunteers and patient populations. However, the first rule in the development of therapeutic agents is safety. Creatine is well-tolerated in most individuals in short-term studies. However, isolated reports suggest creatine may be associated with various side effects affecting several organ systems including skeletal muscle, the kidney and the gastrointestinal tract. The majority of clinical studies fail to find an increased incidence of side effects with creatine supplementation. To date, studies have not found clinically significant deviations from normal values in renal, hepatic, cardiac or muscle function. Few data are available on the long-term consequences of creatine supplementation.
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Affiliation(s)
- Adam M Persky
- Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7360, USA
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Ganio MS, Casa DJ, Armstrong LE, Maresh CM. Evidence-Based Approach to Lingering Hydration Questions. Clin Sports Med 2007; 26:1-16. [PMID: 17241912 DOI: 10.1016/j.csm.2006.11.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Studies related to fundamental hydration issues have required clinicians to re-examine certain practices and concepts. The ingestion of substances such as creatine, caffeine, and glycerol has been questioned in regards to safety and hydration status. Reports of overdrinking (hyponatremia) also have brought into question the practices of drinking appropriate fluid amounts and the role that fluid-electrolyte balance has in the etiology of heat illnesses such as heat cramps. This article offers a fresh perspective on timely topics related to hydration, fluid balance, and exercise in the heat.
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Affiliation(s)
- Matthew S Ganio
- Human Performance Laboratory, Department of Kinesiology, University of Connecticut, 2095 Hillside Road, U-1110, Storrs, CT 06269-1110, USA
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Abstract
Exertional heat stroke (EHS) is a serious medical condition that can have a tragic outcome if proper assessment and treatment are not initiated rapidly. This article focuses on critical misconceptions that pertain to the prevention, recognition, and treatment of EHS, including 1) the randomness of EHS cases, 2) the role of nutritional supplements in EHS, 3) temperature assessment, 4) onset of EHS and the possible lucid interval, 5) rapid cooling, and 6) return to play. Exploration of these topics will enhance the medical care regarding EHS.
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Affiliation(s)
- Douglas J Casa
- Human Performance Laboratory, Department of Kinesiology, Neag School of Education, University of Connecticut, 2095 Hillside Road, U-1110, Storrs, CT 06269-1110, USA.
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