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Brown HA, Topham TH, Clark B, Ioannou LG, Flouris AD, Smallcombe JW, Telford RD, Jay O, Périard JD. Quantifying Exercise Heat Acclimatisation in Athletes and Military Personnel: A Systematic Review and Meta-analysis. Sports Med 2023:10.1007/s40279-023-01972-4. [PMID: 38051495 DOI: 10.1007/s40279-023-01972-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2023] [Indexed: 12/07/2023]
Abstract
BACKGROUND Athletes and military personnel are often expected to compete and work in hot and/or humid environments, where decrements in performance and an increased risk of exertional heat illness are prevalent. A physiological strategy for reducing the adverse effects of heat stress is to acclimatise to the heat. OBJECTIVE The aim of this systematic review was to quantify the effects of relocating to a hotter climate to undergo heat acclimatisation in athletes and military personnel. ELIGIBILITY CRITERIA Studies investigating the effects of heat acclimatisation in non-acclimatised athletes and military personnel via relocation to a hot climate for < 6 weeks were included. DATA SOURCES MEDLINE, SPORTDiscus, CINAHL Plus with Full Text and Scopus were searched from inception to June 2022. RISK OF BIAS A modified version of the McMaster critical review form was utilised independently by two authors to assess the risk of bias. DATA SYNTHESIS A Bayesian multi-level meta-analysis was conducted on five outcome measures, including resting core temperature and heart rate, the change in core temperature and heart rate during a heat response test and sweat rate. Wet-bulb globe temperature (WBGT), daily training duration and protocol length were used as predictor variables. Along with posterior means and 90% credible intervals (CrI), the probability of direction (Pd) was calculated. RESULTS Eighteen articles from twelve independent studies were included. Fourteen articles (nine studies) provided data for the meta-analyses. Whilst accounting for WBGT, daily training duration and protocol length, population estimates indicated a reduction in resting core temperature and heart rate of - 0.19 °C [90% CrI: - 0.41 to 0.05, Pd = 91%] and - 6 beats·min-1 [90% CrI: - 16 to 5, Pd = 83%], respectively. Furthermore, the rise in core temperature and heart rate during a heat response test were attenuated by - 0.24 °C [90% CrI: - 0.67 to 0.20, Pd = 85%] and - 7 beats·min-1 [90% CrI: - 18 to 4, Pd = 87%]. Changes in sweat rate were conflicting (0.01 L·h-1 [90% CrI: - 0.38 to 0.40, Pd = 53%]), primarily due to two studies demonstrating a reduction in sweat rate following heat acclimatisation. CONCLUSIONS Data from athletes and military personnel relocating to a hotter climate were consistent with a reduction in resting core temperature and heart rate, in addition to an attenuated rise in core temperature and heart rate during an exercise-based heat response test. An increase in sweat rate is also attainable, with the extent of these adaptations dependent on WBGT, daily training duration and protocol length. PROSPERO REGISTRATION CRD42022337761.
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Affiliation(s)
- Harry A Brown
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Thomas H Topham
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Brad Clark
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Leonidas G Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - James W Smallcombe
- Faculty of Medicine and Health, Heat and Health Research Incubator, The University of Sydney, Sydney, NSW, Australia
| | - Richard D Telford
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia
| | - Ollie Jay
- Faculty of Medicine and Health, Heat and Health Research Incubator, The University of Sydney, Sydney, NSW, Australia
| | - Julien D Périard
- Research Institute for Sport and Exercise (UCRISE), University of Canberra, Bruce, ACT, Australia.
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Wheelock CE, Looney DP, Potter AW, Pryor RR, Pryor JL, Florian J, Hostler D. Diver Underwater Cycling Endurance After Short-Term Warm and Hot Water Acclimation. Mil Med 2023; 188:3071-3078. [PMID: 35822881 DOI: 10.1093/milmed/usac204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/11/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
INTRODUCTION It is unclear whether immersion heat acclimation benefits exercise in warm water conditions. This study examined the effects of heat acclimation strategies on heart rate (HR), core temperature, and time to exhaustion (TTE) during cycling exercise in varying warm water conditions. METHODS Twenty male divers completed this study at the Navy Experimental Diving Unit. Subjects were randomly assigned to one of two 9-day heat acclimation groups. The first group (WARM; n = 10) cycled for 2 hours at 50 W in 34.4 °C water, while the second group (HOT; n = 10) cycled for 1 hour against minimal resistance in 36.7 °C water. Following acclimation, TTE was tested by underwater cycling (30 W) in 35.8 °C, 37.2 °C, and 38.6 °C water. RESULTS Throughout acclimation, the rate of core temperature rise in the first 30 minutes of exercise increased (P = .02), but the maximum core temperature reached was not different for either group. Time to exhaustion (TTE) was reduced, and the rate of core temperature rise during performance testing increased (both P < .001) with increasing water temperature but was not different between groups. Core temperature and HR increased throughout performance testing in each water condition and were lower in the HOT compared to the WARM acclimation group (all P < .05) with the exception of core temperature in the 37.2 °C condition. CONCLUSIONS Underwater exercise performance did not differ between the two acclimation strategies. This study suggests that passive acclimation to a higher water temperature may improve thermoregulatory and cardiovascular responses to exercise in warm water. Hot water immersion adaptations are dependent on exercise intensity and water temperature.
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Affiliation(s)
- Courtney E Wheelock
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - David P Looney
- Military Performance Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA 01760, USA
| | - Adam W Potter
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine (USARIEM), Natick, MA 01760, USA
| | - Riana R Pryor
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - J Luke Pryor
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
| | - John Florian
- Navy Experimental Diving Unit (NEDU), Panama City, FL 32407, USA
| | - David Hostler
- Center for Research and Education in Special Environments (CRESE), Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA
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Chalmers S, Shaw G, Mujika I, Jay O. Thermal Strain During Open-Water Swimming Competition in Warm Water Environments. Front Physiol 2022; 12:785399. [PMID: 35002767 PMCID: PMC8733577 DOI: 10.3389/fphys.2021.785399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Open-water swim racing in warm water is associated with significant physiological strain. However, existing international policy that governs safe participation during competition relies only on a fixed water temperature threshold for event cancellation and has an unclear biophysical rationale. The current policy does not factor other environmental factors or race distance, nor provide a stratification of risk (low, moderate, high, or extreme) prior to the threshold for cancellation. Therefore, the primary aim of this Perspectives article is to highlight considerations for the development of modernized warm-water competition policies. We highlight current accounts (or lack thereof) of thermal strain, cooling interventions, and performance in warm-water swimming and opportunities for advancement of knowledge. Further work is needed that systematically evaluate real-world thermal strain and performance during warm water competition (alongside reports of environmental conditions), novel preparatory strategies, and in-race cooling strategies. This could ultimately form a basis for future development of modernized policies for athlete cohorts that stratifies risk and mitigation strategies according to important environmental factors and race-specific factors (distance).
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Affiliation(s)
- Samuel Chalmers
- Alliance for Research in Exercise, Nutrition, and Activity (ARENA), Allied Health and Human Performance, University of South Australia, Adelaide, SA, Australia.,Thermal Ergonomics Laboratory, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
| | - Gregory Shaw
- High Performance Unit, Swimming Australia, Brisbane, QLD, Australia
| | - Iñigo Mujika
- Department of Physiology, Faculty of Medicine and Nursing, University of the Basque Country, Leioa, Spain.,Exercise Science Laboratory, School of Kinesiology, Faculty of Medicine, Universidad Finis Terrae, Santiago, Chile
| | - Ollie Jay
- Thermal Ergonomics Laboratory, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
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Rois S, Zacharakis E, Kounalakis S, Soultanakis HN. Thermoregulatory responses during prolonged swimming with a Wetsuit at 25 °C. INT J PERF ANAL SPOR 2021. [DOI: 10.1080/24748668.2021.1947018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Spyridon Rois
- Aquatics Division, School of Physical Education and Sports Science, Kapodistrian University of Athens, Dafni, Greece
| | - Emmanouil Zacharakis
- Athletic Division, School of Physical Education and Sports Science, Kapodistrian University of Athens, Dafni, Greece
| | - Stylianos Kounalakis
- Department of Physical and Cultural Education, Hellenic Army Academy, Vari, Attiki, Greece
| | - Helen N. Soultanakis
- Aquatics Division, School of Physical Education and Sports Science, Kapodistrian University of Athens, Dafni, Greece
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Hill L, Mountjoy M, Miller J, Burr J. Sink or swim: innovations in aquatic health. J Sports Med Phys Fitness 2021; 61:1104-1114. [PMID: 34137575 DOI: 10.23736/s0022-4707.21.12697-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Since the first modern Olympic Games in 1896, the aquatic sports have expanded both in participation and innovation over the last century. Beginning with swimming, diving, water polo, and later additions of artistic swimming, open water swimming and high diving, the aquatics sports represent a core pillar of Olympic disciplines. The rapid expansion of aquatic disciplines necessitated the foundation of the Fédération Internationale de Natation (FINA) in 1908, to govern the development of aquatic sports. The amateur spectacle has been slowly replaced with an increased focus on health and performance by dedicated professional athletes and support teams, resulting in the development of new innovations. In the early years, innovations largely centered on technical equipment such as bathing suit and springboard design. In more recent years, research and innovation have shifted focus to health and its impact on performance, including but not limited to changes in training methods, nutrition, injury and illness reduction through surveillance and access to education for athletes, coaches, and support personnel. An increased awareness on factors that affect athlete health have also driven safety innovations including the development of Nutrition and Relative Energy Deficiency in Sport Clinical Assessment Tool, the Sport Mental Health Assessment and Recognition Tools and safeguarding from harassment and abuse through embedding athletes' right to safe sport in underpinning statutory documents. While the future of aquatic health innovations remains undefined, there are many potential opportunities for research and knowledge translation as the aquatic sports continue to evolve and adapt over time.
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Affiliation(s)
- Lee Hill
- Department of Pediatrics, McMaster University, Hamilton, ON, Canada -
| | - Margo Mountjoy
- Department of Family Medicine, McMaster University, Hamilton, ON, Canada.,Sports Medicine, FINA, Lausanne, Switzerland
| | - James Miller
- Sports Medicine, FINA, Lausanne, Switzerland.,Department of Medicine, University of Virginia, Charlottesville, VA, USA
| | - Jamie Burr
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Mountjoy M, Engebretsen L. How sport and exercise medicine research can protect athlete health and promote athlete performance. Br J Sports Med 2019; 54:563-564. [DOI: 10.1136/bjsports-2019-100749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2019] [Indexed: 11/03/2022]
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Zurawlew MJ, Mee JA, Walsh NP. Post-exercise Hot Water Immersion Elicits Heat Acclimation Adaptations in Endurance Trained and Recreationally Active Individuals. Front Physiol 2018. [PMID: 30618833 DOI: 10.3389/fphys.2018.01824, 10.3389/fpls.2018.01824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hot water immersion (HWI) after exercise on 6 consecutive days in temperate conditions has been shown to provide heat acclimation adaptations in a recreationally active population. Endurance athletes experience frequent, sustained elevations in body temperature during training and competition; as a consequence, endurance athletes are considered to be partially heat acclimatized. It is therefore important to understand the extent to which endurance trained individuals may benefit from heat acclimation by post-exercise HWI. To this end, we compared the responses of eight endurance trained and eight recreationally active males (habitual weekly endurance exercise: 9 h vs. 3 h) to a 6-day intervention involving a daily treadmill run for 40 min (65% O2max) in temperate conditions followed immediately by HWI (≤40 min, 40°C). Before (PRE) and after the intervention (POST), hallmark heat acclimation adaptations were assessed during a 40-min treadmill run at 65% O2max in the heat (33°C, 40% RH). The 6 day, post-exercise HWI intervention induced heat acclimation adaptations in both endurance trained and recreationally active individuals. Training status did not significantly influence the magnitude of heat acclimation adaptations from PRE to POST (interactions P > 0.05) for: the reduction in end-exercise rectal core temperature (T re, mean, endurance trained -0.36°C; recreationally active -0.47°C); the reduction in resting T re (endurance trained -0.17°C; recreationally active -0.23°C); the reduction in T re at sweating onset (endurance trained -0.22°C; recreationally active -0.23°C); and, the reduction in mean skin temperature (endurance trained -0.67°C; recreationally active -0.75°C: PRE to POST P < 0.01). Furthermore, training status did not significantly influence the observed reductions in mean O2, mean metabolic energy expenditure, end-exercise physiological strain index, perceived exertion or thermal sensation (PRE to POST P < 0.05). Only end-exercise heart rate was influenced by training status (P < 0.01, interaction); whereby, recreationally active but not endurance trained individuals experienced a significant reduction in end-exercise heart rate from PRE to POST (P < 0.01). In summary, these findings demonstrate that post-exercise HWI presents a practical strategy to reduce thermal strain during exercise-heat-stress in endurance trained and recreationally active individuals.
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Affiliation(s)
- Michael J Zurawlew
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, United Kingdom
| | - Jessica A Mee
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, United Kingdom
| | - Neil P Walsh
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, United Kingdom
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Zurawlew MJ, Mee JA, Walsh NP. Post-exercise Hot Water Immersion Elicits Heat Acclimation Adaptations in Endurance Trained and Recreationally Active Individuals. Front Physiol 2018; 9:1824. [PMID: 30618833 PMCID: PMC6305481 DOI: 10.3389/fphys.2018.01824] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 12/06/2018] [Indexed: 11/13/2022] Open
Abstract
Hot water immersion (HWI) after exercise on 6 consecutive days in temperate conditions has been shown to provide heat acclimation adaptations in a recreationally active population. Endurance athletes experience frequent, sustained elevations in body temperature during training and competition; as a consequence, endurance athletes are considered to be partially heat acclimatized. It is therefore important to understand the extent to which endurance trained individuals may benefit from heat acclimation by post-exercise HWI. To this end, we compared the responses of eight endurance trained and eight recreationally active males (habitual weekly endurance exercise: 9 h vs. 3 h) to a 6-day intervention involving a daily treadmill run for 40 min (65% O2max) in temperate conditions followed immediately by HWI (≤40 min, 40°C). Before (PRE) and after the intervention (POST), hallmark heat acclimation adaptations were assessed during a 40-min treadmill run at 65% O2max in the heat (33°C, 40% RH). The 6 day, post-exercise HWI intervention induced heat acclimation adaptations in both endurance trained and recreationally active individuals. Training status did not significantly influence the magnitude of heat acclimation adaptations from PRE to POST (interactions P > 0.05) for: the reduction in end-exercise rectal core temperature (Tre, mean, endurance trained -0.36°C; recreationally active -0.47°C); the reduction in resting Tre (endurance trained -0.17°C; recreationally active -0.23°C); the reduction in Tre at sweating onset (endurance trained -0.22°C; recreationally active -0.23°C); and, the reduction in mean skin temperature (endurance trained -0.67°C; recreationally active -0.75°C: PRE to POST P < 0.01). Furthermore, training status did not significantly influence the observed reductions in mean O2, mean metabolic energy expenditure, end-exercise physiological strain index, perceived exertion or thermal sensation (PRE to POST P < 0.05). Only end-exercise heart rate was influenced by training status (P < 0.01, interaction); whereby, recreationally active but not endurance trained individuals experienced a significant reduction in end-exercise heart rate from PRE to POST (P < 0.01). In summary, these findings demonstrate that post-exercise HWI presents a practical strategy to reduce thermal strain during exercise-heat-stress in endurance trained and recreationally active individuals.
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Affiliation(s)
- Michael J Zurawlew
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, United Kingdom
| | - Jessica A Mee
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, United Kingdom
| | - Neil P Walsh
- Extremes Research Group, College of Human Sciences, Bangor University, Bangor, United Kingdom
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Myburgh C, Hansen T, Holm Beck A, Boyle E. Cracking the code for maintaining quality training in Olympic distance triathlon: lessons learnt from a squad of elite Scandinavian athletes. BMJ Open Sport Exerc Med 2017; 3:e000274. [PMID: 29071114 PMCID: PMC5640110 DOI: 10.1136/bmjsem-2017-000274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2017] [Indexed: 11/17/2022] Open
Abstract
Objective High-quality training is a key determinant of performance in the Olympic distance triathlon and is potentially influenced by a unique array of context-specific biopsychosocial factors. Our objective was to explore and describe these factors among squad members of a university-based, elite Olympic distance triathlete developmental programme. Method A qualitative investigation using a visual communication tool-assisted focus group and longitudinal semistructured individual interviews was conducted. Responses were solicited from the University of Southern Denmark’s elite triathlon team (n=8), and inductive coding from the focus group formed the basis of questions for the two rounds of individual interviews 11 months apart. All interviews were transcribed verbatim and then analysed thematically. Results Seventeen context-relevant factors were identified and 10 themes emerged, these being ‘the cold weather ritual’, ‘digestive system conditioning’, ‘the curse of the night owl’, ‘the strings attached to sponsorship’, ‘my coach—my rock’, ‘mood maintenance’, ‘the asynchronous training rhythm’, ‘psychological slavery’, ‘the legacy of the asphalt tattoo’ and ‘the tension of family and friends’. Conclusions By reflecting on their personal training vortex, elite triathletes were able to provide context-relevant insights into the maintenance of training quality over the course of a competitive season. Further research is required to elucidate whether and how biopsycholosocial factors can be modified to optimise the achievement of training goals.
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Affiliation(s)
- Corrie Myburgh
- Department of Sports and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Tobias Hansen
- Department of Sports and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Anders Holm Beck
- Department of Sports and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Eleanor Boyle
- Department of Sports and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.,Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
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Akerman AP, Tipton M, Minson CT, Cotter JD. Heat stress and dehydration in adapting for performance: Good, bad, both, or neither? Temperature (Austin) 2016; 3:412-436. [PMID: 28349082 PMCID: PMC5356617 DOI: 10.1080/23328940.2016.1216255] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 07/15/2016] [Accepted: 07/20/2016] [Indexed: 01/14/2023] Open
Abstract
Physiological systems respond acutely to stress to minimize homeostatic disturbance, and typically adapt to chronic stress to enhance tolerance to that or a related stressor. It is legitimate to ask whether dehydration is a valuable stressor in stimulating adaptation per se. While hypoxia has had long-standing interest by athletes and researchers as an ergogenic aid, heat and nutritional stressors have had little interest until the past decade. Heat and dehydration are highly interlinked in their causation and the physiological strain they induce, so their individual roles in adaptation are difficult to delineate. The effectiveness of heat acclimation as an ergogenic aid remains unclear for team sport and endurance athletes despite several recent studies on this topic. Very few studies have examined the potential ergogenic (or ergolytic) adaptations to ecologically-valid dehydration as a stressor in its own right, despite longstanding evidence of relevant fluid-regulatory adaptations from short-term hypohydration. Transient and self-limiting dehydration (e.g., as constrained by thirst), as with most forms of stress, might have a time and a place in physiological or behavioral adaptations independently or by exacerbating other stressors (esp. heat); it cannot be dismissed without the appropriate evidence. The present review did not identify such evidence. Future research should identify how the magnitude and timing of dehydration might augment or interfere with the adaptive processes in behaviorally constrained versus unconstrained humans.
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Affiliation(s)
- Ashley Paul Akerman
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago , New Zealand
| | - Michael Tipton
- Extreme Environments Laboratory, Department of Sport & Exercise Science, University of Portsmouth , UK
| | | | - James David Cotter
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago , New Zealand
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Mountjoy M, Dijkstra HP. Swimming in H2O: two parts heart + one part obsession. Br J Sports Med 2016; 50:568-9. [PMID: 27127295 DOI: 10.1136/bjsports-2015-095681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2016] [Indexed: 11/04/2022]
Affiliation(s)
- M Mountjoy
- Department of Family Medicine, Michael G DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada IOC Medical Commission-Games Group FINA Bureau; Sport Medicine Liaison
| | - H P Dijkstra
- Sports Medicine Department, Aspetar Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
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Minson CT, Cotter JD. CrossTalk proposal: Heat acclimatization does improve performance in a cool condition. J Physiol 2015; 594:241-3. [PMID: 26668072 DOI: 10.1113/jp270879] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 10/22/2015] [Indexed: 11/08/2022] Open
Abstract
We believe available data support the thesis that HA can improve performance in cool conditions, and perhaps with less expense and fewer side-effects than hypoxia (Dempsey & Morgan, 2015), but its utility is unresolved and may be modest or absent in some settings and individuals. A few key issues are becoming clear, however. First, HA must be of sufficient stimulus and duration, with key evidence indicating longer is better. Second, individual variability in response to HA as an ergogenic aid needs to be considered. Third, key training aspects such as speed and intensity may need to be maintained, and ideally performed in a cooler environment to maximize gains and minimize fatigue (including the effects of matched absolute versus relative work rates on adaptations). Alternatively, passive heating should be considered (e.g. immediately after training). Fourth, there is no evidence that HA impairs cool weather performance, and thus HA is a useful strategy when the competitive environmental conditions are potentially hot or unknown. Fifth, much remains unknown about ideal timing for competition following HA and its decay. Lastly, an ergogenic effect of HA has yet to be studied in truly elite athletes.
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Affiliation(s)
| | - James D Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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