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Willmott AGB, Diment AG, Chung HC, James CA, Maxwell NS, Roberts JD, Gibson OR. Cross-adaptation from heat stress to hypoxia: A systematic review and exploratory meta-analysis. J Therm Biol 2024; 120:103793. [PMID: 38471285 DOI: 10.1016/j.jtherbio.2024.103793] [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: 06/18/2023] [Revised: 01/03/2024] [Accepted: 01/12/2024] [Indexed: 03/14/2024]
Abstract
Cross-adaptation (CA) refers to the successful induction of physiological adaptation under one environmental stressor (e.g., heat), to enable subsequent benefit in another (e.g., hypoxia). This systematic review and exploratory meta-analysis investigated the effect of heat acclimation (HA) on physiological, perceptual and physical performance outcome measures during rest, and submaximal and maximal intensity exercise in hypoxia. Database searches in Scopus and MEDLINE were performed. Studies were included when they met the Population, Intervention, Comparison, and Outcome criteria, were of English-language, peer-reviewed, full-text original articles, using human participants. Risk of bias and study quality were assessed using the COnsensus based Standards for the selection of health status Measurement INstruments checklist. Nine studies were included, totalling 79 participants (100 % recreationally trained males). The most common method of HA included fixed-intensity exercise comprising 9 ± 3 sessions, 89 ± 24-min in duration and occurred within 39 ± 2 °C and 32 ± 13 % relative humidity. CA induced a moderate, beneficial effect on physiological measures at rest (oxygen saturation: g = 0.60) and during submaximal exercise (heart rate: g = -0.65, core temperature: g = -0.68 and skin temperature: g = -0.72). A small effect was found for ventilation (g = 0.24) and performance measures (peak power: g = 0.32 and time trial time: g = -0.43) during maximal intensity exercise. No effect was observed for perceptual outcome measures. CA may be appropriate for individuals, such as occupational or military workers, whose access to altitude exposure prior to undertaking submaximal activity in hypoxic conditions is restricted. Methodological variances exist within the current literature, and females and well-trained individuals have yet to be investigated. Future research should focus on these cohorts and explore the mechanistic underpinnings of CA.
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Affiliation(s)
- Ashley G B Willmott
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom; Environmental Extremes Laboratory, University of Brighton, Eastbourne, East Sussex, United Kingdom; Para-Monte Altitude Awareness Charity, Eastbourne, East Sussex, United Kingdom.
| | - Alicia G Diment
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom; Pulmonary Function Laboratory, Norfolk and Norwich University Hospital, Colney Lane, Norwich, Norfolk, United Kingdom.
| | - Henry C Chung
- School of Sport, Rehabilitation and Exercise Sciences (SRES), University of Essex, Colchester, Essex, United Kingdom.
| | - Carl A James
- Hong Kong Sports Institute, Sha Tin, Hong Kong, China; Department of Sport, Physical Education and Health, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
| | - Neil S Maxwell
- Environmental Extremes Laboratory, University of Brighton, Eastbourne, East Sussex, United Kingdom; Para-Monte Altitude Awareness Charity, Eastbourne, East Sussex, United Kingdom.
| | - Justin D Roberts
- The Cambridge Centre for Sport and Exercise Sciences (CCSES), Anglia Ruskin University, East Road, Cambridge, United Kingdom.
| | - Oliver R Gibson
- Centre for Physical Activity in Health and Disease (CPAHD), Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, United Kingdom.
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Matias AA, Albin IF, Glickman L, Califano PA, Faller JM, Layec G, Ives SJ. Impact of high intensity interval exercise with and without heat stress on cardiovascular and aerobic performance: a pilot study. BMC Sports Sci Med Rehabil 2023; 15:83. [PMID: 37434243 DOI: 10.1186/s13102-023-00682-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 06/21/2023] [Indexed: 07/13/2023]
Abstract
BACKGROUND Heat stress during aerobic exercise training may offer an additional stimulus to improve cardiovascular function and performance in a cool-temperate environment. However, there is a paucity of information on the additive effects of high-intensity interval exercise (HIIE) and acute heat stress. We aimed to determine the effects of HIIE in combination with acute heat stress on cardiovascular function and exercise performance. METHODS Twelve active (peak O2 consumption [VO2peak]: 47 ± 8 ml·O2/min/kg) young adults were counterbalanced to six sessions of HIIE in hot (HIIE-H, 30 ± 1 °C, 50 ± 5% relative humidity [RH]) or temperate conditions (HIIE-T, 20 ± 2 °C, 15 ± 10% RH). Resting heart rate (HR), HR variability (HRV), central (cBP) and peripheral blood pressure (pBP), peripheral mean arterial pressure (pMAP), pulse wave velocity (PWV), VO2peak, and 5-km treadmill time-trial were measured pre- and post-training. RESULTS Resting HR and HRV were not significantly different between groups. However, expressed as percent change from baseline, cSBP (HIIE-T: + 0.9 ± 3.6 and HIIE-H: -6.6 ± 3.0%, p = 0.03) and pSBP (HIIE-T: -2.0 ± 4.6 and HIIE-H: -8.4 ± 4.7%, p = 0.04) were lower in the heat group. Post-training PWV was also significantly lower in the heat group (HIIE-T: + 0.4% and HIIE-H: -6.3%, p = 0.03). Time-trial performance improved with training when data from both groups were pooled, and estimated VO2peak was not significantly different between groups (HIIE-T: 0.7% and HIIE-H: 6.0%, p = 0.10, Cohen's d = 1.4). CONCLUSIONS The addition of acute heat stress to HIIE elicited additive adaptations in only cardiovascular function compared to HIIE alone in active young adults in temperate conditions, thus providing evidence for its effectiveness as a strategy to amplify exercise-induced cardiovascular adaptations.
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Affiliation(s)
- Alexs A Matias
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
- Department of Kinesiology, University of Massachusetts at Amherst, Amherst, MA, USA
| | - Isabelle F Albin
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Leah Glickman
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Peter A Califano
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Justin M Faller
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA
| | - Gwenael Layec
- Department of Kinesiology, University of Massachusetts at Amherst, Amherst, MA, USA
- Institute for Applied Life Sciences, University of Massachusetts, Amherst, MA, USA
| | - Stephen J Ives
- Department of Health and Human Physiological Sciences, Skidmore College, 815 N. Broadway, Saratoga Springs, NY, 12866, USA.
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Kelly MK, Bowe SJ, Jardine WT, Condo D, Guy JH, Snow RJ, Carr AJ. Heat Adaptation for Females: A Systematic Review and Meta-Analysis of Physiological Adaptations and Exercise Performance in the Heat. Sports Med 2023; 53:1395-1421. [PMID: 37222863 PMCID: PMC10289939 DOI: 10.1007/s40279-023-01831-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2023] [Indexed: 05/25/2023]
Abstract
BACKGROUND Heat adaptation regimes are used to prepare athletes for exercise in hot conditions to limit a decrement in exercise performance. However, the heat adaptation literature mostly focuses on males, and consequently, current heat adaptation guidelines may not be optimal for females when accounting for the biological and phenotypical differences between sexes. OBJECTIVES We aimed to examine: (1) the effects of heat adaptation on physiological adaptations in females; (2) the impact of heat adaptation on performance test outcomes in the heat; and (3) the impact of various moderators, including duration (minutes and/or days), total heat dose (°C.min), exercise intensity (kcal.min-1), total energy expended (kcal), frequency of heat exposures and training status on the physiological adaptations in the heat. METHODS SPORTDiscus, MEDLINE Complete and Embase databases were searched to December 2022. Random-effects meta-analyses for resting and exercise core temperature, skin temperature, heart rate, sweat rate, plasma volume and performance tests in the heat were completed using Stata Statistical Software: Release 17. Sub-group meta-analyses were performed to explore the effect of duration, total heat dose, exercise intensity, total energy expended, frequency of heat exposure and training status on resting and exercise core temperature, skin temperature, heart rate and sweat rate. An explorative meta-regression was conducted to determine the effects of physiological adaptations on performance test outcomes in the heat following heat adaptation. RESULTS Thirty studies were included in the systematic review; 22 studies were meta-analysed. After heat adaptation, a reduction in resting core temperature (effect size [ES] = - 0.45; 95% confidence interval [CI] - 0.69, - 0.22; p < 0.001), exercise core temperature (ES = - 0.81; 95% CI - 1.01, - 0.60; p < 0.001), skin temperature (ES = - 0.64; 95% CI - 0.79, - 0.48; p < 0.001), heart rate (ES = - 0.60; 95% CI - 0.74, - 0.45; p < 0.001) and an increase in sweat rate (ES = 0.53; 95% CI 0.21, 0.85; p = 0.001) were identified in females. There was no change in plasma volume (ES = - 0.03; 95% CI - 0.31, 0.25; p = 0.835), whilst performance test outcomes were improved following heat adaptation (ES = 1.00; 95% CI 0.56, 1.45; p < 0.001). Across all moderators, physiological adaptations were more consistently observed following durations of 451-900 min and/or 8-14 days, exercise intensity ≥ 3.5 kcal.min-1, total energy expended ≥ 3038 kcal, consecutive (daily) frequency and total heat dose ≥ 23,000 °C.min. The magnitude of change in performance test outcomes in the heat was associated with a reduction in heart rate following heat adaptation (standardised mean difference = - 10 beats.min-1; 95% CI - 19, - 1; p = 0.031). CONCLUSIONS Heat adaptation regimes induce physiological adaptations beneficial to thermoregulation and performance test outcomes in the heat in females. Sport coaches and applied sport practitioners can utilise the framework developed in this review to design and implement heat adaptation strategies for females.
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Affiliation(s)
- Monica K Kelly
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia.
| | - Steven J Bowe
- Deakin Biostatistics Unit, Faculty of Health, Deakin University, Burwood, VIC, Australia
- Faculty and School of Health, Victoria University of Wellington, Kelburn, Wellington, New Zealand
| | - William T Jardine
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Dominique Condo
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
| | - Joshua H Guy
- School of Health, Medical and Applied Sciences, Central Queensland University, Cairns, QLD, Australia
| | - Rodney J Snow
- Institute for Physical Activity and Nutrition, Deakin University, Burwood, VIC, Australia
| | - Amelia J Carr
- Centre for Sport Research, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia
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Heating Up to Keep Cool: Benefits and Persistence of a Practical Heat Acclimation Protocol in Elite Female Olympic Team-Sport Athletes. Int J Sports Physiol Perform 2023; 18:276-283. [PMID: 36720237 DOI: 10.1123/ijspp.2022-0071] [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: 02/24/2022] [Revised: 10/14/2022] [Accepted: 11/07/2022] [Indexed: 02/02/2023]
Abstract
PURPOSE Although recommendations for effective heat acclimation (HA) strategies for many circumstances exist, best-practice HA protocols specific to elite female team-sport athletes are yet to be established. Therefore, the authors aimed to investigate the effectiveness and retention of a passive HA protocol integrated in a female Olympic rugby sevens team training program. METHODS Twelve elite female rugby sevens athletes undertook 10 days of passive HA across 2 training weeks. Tympanic temperature (TTymp), sweat loss, heart rate, and repeated 6-second cycling sprint performance were assessed using a sport-specific heat stress test Pre-HA, after 3 days (Mid-HA), after 10 days (Post-HA), and 15 days post-HA (Decay). RESULTS Compared with Pre-HA, submaximal TTymp was lower Mid-HA and Post-HA (both by -0.2 [0.7] °C; d ≥ 0.71), while resting TTymp was lower Post-HA (by -0.3 [0.2] °C; d = 0.81). There were no differences in TTymp at Decay compared with Pre-HA, nor were there any differences in heart rate or sweat loss at any time points. Mean peak 6-second power output improved Mid-HA and Post-HA (76 [36] W; 75 [34] W, respectively; d ≥ 0.45) compared with Pre-HA. The observed performance improvement persisted at Decay by 65 (45) W (d = 0.41). CONCLUSIONS Ten days of passive HA can elicit some thermoregulatory and performance benefits when integrated into a training program in elite female team-sport athletes. However, such a protocol does not provide a sufficient thermal impulse for thermoregulatory adaptations to be retained after 15 days with no further heat stimulus.
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Individual variability in achievement of short-term heat acclimation during a fixed intensity protocol. J Therm Biol 2022; 110:103373. [DOI: 10.1016/j.jtherbio.2022.103373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 10/04/2022] [Accepted: 10/12/2022] [Indexed: 12/05/2022]
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Giersch G, Garcia C, Stachenfeld N, Charkoudian N. Are there sex differences in risk for exertional heat stroke? A translational approach. Exp Physiol 2022; 107:1136-1143. [PMID: 35598159 DOI: 10.1113/ep090402] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 05/11/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review discusses the current status of the literature in sex differences in exertional heat stroke. What advances does this review highlight? We utilize a translational model to explore possible physical and physiological differences with respect risk and treatment of exertional heat stroke. ABSTRACT Exertional heat stroke (EHS) is a potentially fatal condition brought about by a combination of physical activity and heat stress and resulting in central nervous system dysfunction and organ damage. EHS impacts several hundred individuals each year ranging from military personnel, athletes, to occupational workers. Understanding the pathophysiology and risk factors can aid in reducing EHS across the globe. While we know there are differences between sexes in mechanisms of thermoregulation, there is currently not a clear understanding if/how those differences impact EHS risk. The purpose of this review is to assess the current status of the literature surrounding EHS from risk factors to treatment using both animal and human models. We use a translational approach, considering both animal and human research to elucidate the possible influence of female sex hormones on temperature regulation and performance in the heat and highlight the specific areas with limited research. While more work is necessary to comprehensively understand these differences, the current research presented provides a good framework for future investigations. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Gabrielle Giersch
- Thermal and Mountain Medicine Division, U.S. Army Research Institute for Environmental Medicine, Natick, MA, USA.,Oak Ridge Institute for Science and Education, Belcamp, MD, USA
| | - Christian Garcia
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL, USA
| | - Nina Stachenfeld
- John B. Pierce Laboratory, Yale School of Medicine, New Haven, CT, USA
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, U.S. Army Research Institute for Environmental Medicine, Natick, MA, USA
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Sex Differences in VO 2max and the Impact on Endurance-Exercise Performance. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19094946. [PMID: 35564339 PMCID: PMC9105160 DOI: 10.3390/ijerph19094946] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/15/2022] [Indexed: 02/04/2023]
Abstract
It was not until 1984 that women were permitted to compete in the Olympic marathon. Today, more women than men participate in road racing in all distances except the marathon where participation is near equal. From the period of 1985 to 2004, the women’s marathon record improved at a rate three times greater than men’s. This has led many to question whether women are capable of surpassing men despite the fact that there remains a 10–12% performance gap in all distance events. The progressive developments in sports performance research and training, beginning with A.V. Hill’s establishment of the concept of VO2max, have allowed endurance athletes to continue performance feats previously thought to be impossible. However, even today women are significantly underrepresented in sports performance research. By focusing more research on the female physiology and sex differences between men and women, we can better define how women differ from men in adapting to training and potentially use this information to improve endurance-exercise performance in women. The male advantage in endurance-exercise performance has commonly been attributed to their higher VO2max, even when expressed as mL/kg/min. It is widely known that oxygen delivery is the primary limiting factor in elite athletes when it comes to improving VO2max, but little research has explored the sex differences in oxygen delivery. Thus, the purpose of this review is to highlight what is known about the sex differences in the physiological factors contributing to VO2max, more specifically oxygen delivery, and the impacts on performance.
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Giersch GEW, Charkoudian N, McClung HL. The Rise of the Female Warfighter: Physiology, Performance, and Future Directions. Med Sci Sports Exerc 2021; 54:683-691. [PMID: 34939610 DOI: 10.1249/mss.0000000000002840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ABSTRACT Since 1948, the United States military has been open to both men and women as permanent party service members. However, in the majority of the time since, there have been a subset of military occupational specialties (MOS), or job descriptions, open only to men. In particular, jobs requiring more intense physical and/or environmental strain were considered to be beyond the physiological capabilities of women. In the present analysis, we review the literature regarding neuromuscular, physical performance, and environmental physiology in women, to highlight that women have no inherent limitation in their capacity to participate in relevant roles and jobs within the military, within accepted guidelines to promote risk mitigation across sexes. First, we discuss performance and injury risk: both neuromuscular function and physical capabilities. Second, physiological responses to environmental stress. Third, we discuss risk as it relates to reproductive health and nutritional considerations. We conclude with a summary of current physiological, performance and injury risk data in men and women that support our overarching purpose, as well as suggestions for future directions.
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Affiliation(s)
- Gabrielle E W Giersch
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA Biophysical and Biomedical Modeling Division, United States Army Research Institute of Environmental Medicine, Natick, MA Oak Ridge Institute for Science and Technology, Oak Ridge, TN
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Kirby NV, Lucas SJE, Cable TG, Armstrong OJ, Weaver SR, Lucas RAI. Sex differences in adaptation to intermittent post-exercise sauna bathing in trained middle-distance runners. SPORTS MEDICINE-OPEN 2021; 7:51. [PMID: 34297227 PMCID: PMC8302716 DOI: 10.1186/s40798-021-00342-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/30/2021] [Indexed: 11/16/2022]
Abstract
Background The purpose of this study was to investigate the effect of sex on the efficacy of intermittent post-exercise sauna bathing to induce heat acclimation and improve markers of temperate exercise performance in trained athletes. Methods Twenty-six trained runners (16 female; mean ± SD, age 19 ± 1 years, V̇O2max F: 52.6 ± 6.9 mL⋅kg−1⋅min−1, M: 64.6 ± 2.4 mL⋅kg−1⋅min−1) performed a running heat tolerance test (30 min, 9 km⋅h−1/2% gradient, 40 °C/40%RH; HTT) and temperate (18 °C) exercise tests (maximal aerobic capacity [V̇O2max] and lactate profile) pre and post 3 weeks of normal exercise training plus 29 ± 1 min post-exercise sauna bathing (101–108 °C) 3 ± 1 times per week. Results Females and males exhibited similar reductions (interactions p > 0.05) in peak rectal temperature (− 0.3 °C; p < 0.001), skin temperature (− 0.9 °C; p < 0.001) and heart rate (− 9 beats·min−1; p = 0.001) during the HTT at post- vs pre-intervention. Only females exhibited an increase in active sweat glands on the forearm (measured via modified iodine technique; F: + 57%, p < 0.001; M: + 1%, p = 0.47). Conversely, only males increased forearm blood flow (measured via venous occlusion plethysmography; F: + 31%, p = 0.61; M: + 123%; p < 0.001). Females and males showed similar (interactions p > 0.05) improvements in V̇O2max (+ 5%; p = 0.02) and running speed at 4 mmol·L−1 blood lactate concentration (+ 0.4 km·h−1; p = 0.001). Conclusions Three weeks of post-exercise sauna bathing effectively induces heat acclimation in females and males, though possibly amid different thermoeffector adaptations. Post-exercise sauna bathing is also an effective ergogenic aid for both sexes. Supplementary Information The online version contains supplementary material available at 10.1186/s40798-021-00342-6.
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Affiliation(s)
- Nathalie V Kirby
- School of Sport Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK. .,Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, K1N 6N5, Canada.
| | - Samuel J E Lucas
- School of Sport Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Thomas G Cable
- School of Sport Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.,Loughborough University, Loughborough, UK
| | | | - Samuel R Weaver
- School of Sport Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Rebekah A I Lucas
- School of Sport Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
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Adams WM, Hosokawa Y, Casa DJ, Périard JD, Racinais S, Wingo JE, Yeargin SW, Scarneo-Miller SE, Kerr ZY, Belval LN, Alosa D, Csillan D, LaBella C, Walker L. Roundtable on Preseason Heat Safety in Secondary School Athletics: Heat Acclimatization. J Athl Train 2021; 56:352-361. [PMID: 33878177 DOI: 10.4085/1062-6050-596-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To provide best-practice recommendations for developing and implementing heat-acclimatization strategies in secondary school athletics. DATA SOURCES An extensive literature review on topics related to heat acclimatization and heat acclimation was conducted by a group of content experts. Using the Delphi method, action-oriented recommendations were developed. CONCLUSIONS A period of heat acclimatization consisting of ≥14 consecutive days should be implemented at the start of fall preseason training or practices for all secondary school athletes to mitigate the risk of exertional heat illness. The heat-acclimatization guidelines should outline specific actions for secondary school athletics personnel to use, including the duration of training, the number of training sessions permitted per day, and adequate rest periods in a cool environment. Further, these guidelines should include sport-specific and athlete-specific recommendations, such as phasing in protective equipment and reintroducing heat acclimatization after periods of inactivity. Heat-acclimatization guidelines should be clearly detailed in the secondary school's policy and procedures manual and disseminated to all stakeholders. Heat-acclimatization guidelines, when used in conjunction with current best practices surrounding the prevention, management, and care of secondary school student-athletes with exertional heat stroke, will optimize their health and safety.
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Affiliation(s)
- William M Adams
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
| | - Sebastien Racinais
- Research and Scientific Support Department, ASPETAR Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | | | - Susan W Yeargin
- Department of Exercise Science, University of South Carolina, Columbia
| | | | - Zachary Y Kerr
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill
| | - Luke N Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas
| | - Denise Alosa
- Athletic Medicine, South Burlington School District, Burlington, VT.,College of Nursing and Health Science, University of Vermont, Burlington
| | - David Csillan
- Department of Physical Therapy, Princeton Orthopedic Associates, NJ
| | - Cynthia LaBella
- Department of Pediatrics, Northwestern University Feinberg School of Medicine Institute for Sports Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, IL
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Wardenaar FC, Ortega-Santos CP, Vento KAS, Beaumont JS, Griffin SC, Johnston C, Kavouras SA. A 5-day Heat Acclimation Program Improves Heat Stress Indicators While Maintaining Exercise Capacity. J Strength Cond Res 2021; 35:1279-1286. [PMID: 33900261 DOI: 10.1519/jsc.0000000000003970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Wardenaar, FC, Ortega-Santos, CP, Vento, K, Beaumont, JS, Griffin, SC, Johnston, C, and Kavouras, SA. A 5-day heat acclimation program improves heat stress indicators while maintaining exercise capacity. J Strength Cond Res 35(5): 1279-1286, 2021-This study aimed to evaluate whether a daily 60 minutes isothermic biking protocol during a 5-day period could improve physiological heat acclimation and exercise performance capacity in partially acclimated subjects. A quasi-experimental study consisted of an intervention (INT, n = 7) and control (CON, n = 7) group completing 2 12 minutes Cooper tests (pre-CT on day 1 and post-CT on day 7) and a heat stress test (HST, on day 9). INT performed additional intensive exercise 1 hour per day on days 1-5, whereas CON did not. During CTs and HST, core temperature (Tc, telemetric capsule), skin temperature (Tsk, sensors at neck, right shoulder, left hand, and right shin), and heart rate (HR, chest strap) were continuously monitored and baseline, average, peak, and increment were calculated. During the HST, the INT group showed a smaller baseline-peak Tc increment (INT 0.88 ± 0.27 vs. CON 1.64 ± 0.90° C, p = 0.02), a lower HR peak (150.2 ± 12.6 vs. 173.0 ± 16.8 b·min-1, p = 0.02), and lower Tsk peak (36.47 ± 0.62 vs. 36.54 ± 0.46° C, p = 0.04). There was a nonsignificant, but practical difference based on a moderate effect size for change in pre-CT to post-CT performance of nearly +2.7 ± 12.3% in INT and -3.0 ± 8.5% in CON (p = 0.32 and d = 0.51), and HST distance covered resulting in a nonsignificant difference of 464 ± 849 m between INT and CON (p = 0.38 and d = 0.44). In conclusion a short-term 5-day heat acclimation program including 300 minutes of extra exercise resulted in positive physiological adaptions to heat stress, as indicated by lower core temperature and HR in comparison with a control group.
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Affiliation(s)
- Floris C Wardenaar
- Athleat Field Lab, College of Health Solutions, Arizona State University, Phoenix, Arizona
| | - Carmen P Ortega-Santos
- Athleat Field Lab, College of Health Solutions, Arizona State University, Phoenix, Arizona
| | - Kaila A S Vento
- Athleat Field Lab, College of Health Solutions, Arizona State University, Phoenix, Arizona
| | - Joshua S Beaumont
- Athleat Field Lab, College of Health Solutions, Arizona State University, Phoenix, Arizona
- Sun Devil Athletics, Arizona State University, Tempe, Arizona
| | - Stephanie C Griffin
- Mel and Enid Zuckerman College of Public Health, University of Arizona, Tucson, Arizona; and
| | - Carol Johnston
- Athleat Field Lab, College of Health Solutions, Arizona State University, Phoenix, Arizona
- College of Health Solutions, Arizona State University, Phoenix, Arizona
| | - Stavros A Kavouras
- Athleat Field Lab, College of Health Solutions, Arizona State University, Phoenix, Arizona
- College of Health Solutions, Arizona State University, Phoenix, Arizona
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Effects of Heat Acclimation and Acclimatisation on Maximal Aerobic Capacity Compared to Exercise Alone in Both Thermoneutral and Hot Environments: A Meta-Analysis and Meta-Regression. Sports Med 2021; 51:1509-1525. [PMID: 33811616 PMCID: PMC8222027 DOI: 10.1007/s40279-021-01445-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2021] [Indexed: 11/25/2022]
Abstract
Background Heat acclimation and acclimatisation (HA) is typically used to enhance tolerance to the heat, thereby improving performance. HA might also confer a positive adaptation to maximal oxygen consumption (\documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max), although this has been historically debated and requires clarification via meta-analysis. Objectives (1) To meta-analyse all studies (with and without control groups) that have investigated the effect of HA on \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max adaptation in thermoneutral or hot environments; (2) Conduct meta-regressions to establish the moderating effect of selected variables on \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max adaptation following HA. Methods A search was performed using various databases in May 2020. The studies were screened using search criteria for eligibility. Twenty-eight peer-reviewed articles were identified for inclusion across four separate meta-analyses: (1) Thermoneutral \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max within-participants (pre-to-post HA); (2) Hot \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max within-participants (pre-to-post HA); (3) Thermoneutral \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max measurement; HA vs. control groups; (4) Hot \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max measurement, HA vs. control groups. Meta-regressions were performed for each meta-analysis based on: isothermal vs. iso-intensity programmes, days of heat exposure, HA ambient temperature (°C), heat index, HA session duration (min), ambient thermal load (HA session x ambient temperature), mean mechanical intensity (W) and the post-HA testing period (days). Results The meta-analysis of pre–post differences in thermoneutral \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max demonstrated small-to-moderate improvements in \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max (Hedges’ g = 0.42, 95% CI 0.24–0.59, P < 0.001), whereas moderate improvements were found for the equivalent analysis of hot \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max changes (Hedges’ g = 0.63, 95% CI 0.26–1.00, P < 0.001), which were positively moderated by the number of days post-testing (P = 0.033, β = 0.172). Meta-analysis of control vs. HA thermoneutral \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max demonstrated a small improvement in \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max in HA compared to control (Hedges’ g = 0.30, 95% CI 0.06–0.54, P = 0.014) and this effect was larger for the equivalent hot \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max analysis where a higher (moderate-to-large) improvement in \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max was found (Hedges’ g = 0.75, 95% CI 0.22–1.27, P = 0.005), with the number of HA days (P = 0.018; β = 0.291) and the ambient temperature during HA (P = 0.003; β = 0.650) positively moderating this effect. Conclusion HA can enhance \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max adaptation in thermoneutral or hot environments, with or without control group consideration, by at least a small and up to a moderate–large amount, with the larger improvements occurring in the heat. Ambient heat, number of induction days and post-testing days can explain some of the changes in hot \documentclass[12pt]{minimal}
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\begin{document}$$V{\text{O}}_{2\max }$$\end{document}VO2max adaptation.
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Callovini A, Fornasiero A, Savoldelli A, Stella F, Low DA, Pellegrini B, Schena F, Bortolan L. Effects of three-exercise sessions in the heat on endurance cycling performance. J Therm Biol 2021; 98:102925. [PMID: 34016347 DOI: 10.1016/j.jtherbio.2021.102925] [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: 10/26/2020] [Revised: 03/22/2021] [Accepted: 03/27/2021] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate the effects of a very short-term acclimation protocol (VSTAP) on performance, physiological and perceptual responses to exercise in the heat. METHODS 12 trained male cyclists (age 31.2 ± 7; weight 71.3 ± 7 kg, VO2max: 58.4 ± 3.7 mL/kg/min) randomly performed two Time to Exhaustion Tests (TTE) at 75% of normothermic peak power output (PPO), one in normothermia (N,18°C-50% RH) and one in the heat (H,35°C-50% RH), before and after a VSTAP intervention, consisting of 3 days-90 min exercise (10min at 30% of PPO+80 min at 50% of PPO) in H (≈4.5h of heat exposure). Performance time of TTEs and physiological and perceptual variables of both TTEs and training sessions (T1, T2 and T3) were evaluated. RESULTS Magnitude Based Inferences (MBI) revealed 92/6/1% and 62/27/11% chances of positive/trivial/negative effects of VSTAP of improving performance in H (+17%) and in N (+9%), respectively. Heart Rate (HR) decreased from T1 to T3 (p < 0.001) and T2 to T3 (p < 0.001), whereas Tympanic Temperature (TyT) decreased from T1 to T2 (p = 0.047) and from T1 to T3 (p = 0.007). Furthermore, despite the increased tolerance to target Power Output (PO) throughout training sessions, RPE decreased from T1 to T3 (p = 0.032). CONCLUSIONS The VSTAP determined meaningful physiological (i.e. decreased HR and TyT) and perceptual (i.e. decreased RPE) adaptations to submaximal exercise. Furthermore, showing good chances to improve performance in the heat, it represents a valid acclimation strategy to be implemented when no longer acclimation period is possible. Finally, no cross-over effect of the VSTAP on performance in temperate conditions was detected.
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Affiliation(s)
- Alexa Callovini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Alessandro Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Aldo Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Federico Stella
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy.
| | - David A Low
- Liverpool John Moores University, Research Institute for Sport and Exercise Sciences (RISES), Liverpool, United Kingdom.
| | - Barbara Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Federico Schena
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Lorenzo Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
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Perez-Quintero M, Siquier-Coll J, Bartolomé I, Robles-Gil MC, Muñoz D, Maynar-Mariño M. Three weeks of passive and intervallic heat at high temperatures (100±2 °C) in a sauna improve acclimation to external heat (42±2 °C) in untrained males. J Therm Biol 2021; 96:102837. [PMID: 33627275 DOI: 10.1016/j.jtherbio.2021.102837] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 12/14/2020] [Accepted: 01/01/2021] [Indexed: 12/28/2022]
Abstract
Currently, the effect of passive heat acclimation on aerobic performance is still controversial. Therefore, this study aimed to observe the effect of passive and intervallic exposure to high temperatures (100 ± 2 °C) in untrained males. Forty healthy untrained men participated in this investigation. They were randomised into a Control Group (CG; n = 18) and an Experimental Group (EG; n = 22). Both groups performed maximum incremental tests until exhaustion in normothermia (GXT1; 22 ± 2 °C), and 48h afterwards, in hyperthermia (GXT2; 42 ± 2 °C). The EG performed 9 sessions of intervallic exposure to heat (100 ± 2 °C) over 3 weeks. Subsequently, both groups performed two maximal incremental trials in normothermia (GXT3; 22 ± 2 °C) and 48h later, in hyperthermia (GXT4; 42 ± 2 °C). In each test, the maximal ergospirometric parameters and the aerobic (VT1), anaerobic (VT2) and recovery ventilatory thresholds were recorded. The Wilcoxon Test was used for intra-group comparisons and the Mann-Whitney U for inter-group comparisons. There were improvements in absolute VO2max (p = 0.049), W (p = 0.005) and O2pulse (p = 0.006) in hyperthermia. In VT1 there was an increase in W (p = 0.046), in VO2 in absolute (p = 0.025) and relative (p = 0.013) values, O2pulse (p = 0.006) and VE (p = 0.028) in hyperthermia. While W increased in hyperthermia (p = 0.022) at VT2. The results suggest that passive and intervallic acclimation at high temperatures improves performance in hyperthermia. This protocol could be implemented in athletes when they have to compete in hot environments.
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Affiliation(s)
- M Perez-Quintero
- Department of Physiology. School of Sport Sciences, University of Extremadura, Spain
| | - J Siquier-Coll
- Department of Physiology. School of Sport Sciences, University of Extremadura, Spain; Movement, Brain and Health Research Group (MOBhE), Center of Higher Education Alberta Giménez (Comillas Pontifical University), Palma de Mallorca, Balearic Islands, Spain.
| | - I Bartolomé
- Department of Physiology. School of Sport Sciences, University of Extremadura, Spain
| | - M C Robles-Gil
- Department of Didactics of Musical, Plastic and Corporal Expression, School of Teacher Training, University of Extremadura, Spain
| | - D Muñoz
- Department of Physical Education and Sport. Sport Sciences Faculty. University of Extremadura, Cáceres, Spain
| | - M Maynar-Mariño
- Department of Physiology. School of Sport Sciences, University of Extremadura, Spain
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15
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Sex differences in the physiological adaptations to heat acclimation: a state-of-the-art review. Eur J Appl Physiol 2020; 121:353-367. [PMID: 33205218 DOI: 10.1007/s00421-020-04550-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 11/02/2020] [Indexed: 02/06/2023]
Abstract
Over the last few decades, females have significantly increased their participation in athletic competitions and occupations (e.g. military, firefighters) in hot and thermally challenging environments. Heat acclimation, which involves repeated passive or active heat exposures that lead to physiological adaptations, is a tool commonly used to optimize performance in the heat. However, the scientific community's understanding of adaptations to heat acclimation are largely based on male data, complicating the generalizability to female populations. Though limited, current evidence suggests that females may require a greater number of heat acclimation sessions or greater thermal stress to achieve the same magnitude of physiological adaptations as males. The underlying mechanisms explaining the temporal sex differences in the physiological adaptations to heat acclimation are currently unclear. Therefore, the aims of this state-of-the-art review are to: (i) present a brief yet comprehensive synthesis of the current female and sex difference literature, (ii) highlight sex-dependent (e.g. anthropometric, menstrual cycle) and sex-independent factors (e.g. environmental conditions, fitness) influencing the physiological and performance adaptations to heat acclimation, and (iii) address key avenues for future research.
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16
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Ko Y, Kang J, Seol SH, Lee JY. Effectiveness of skin-heating using a water-perfused suit as passive and post-exercise heat acclimation strategies. J Therm Biol 2020; 93:102703. [PMID: 33077124 DOI: 10.1016/j.jtherbio.2020.102703] [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] [Received: 03/30/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 11/26/2022]
Abstract
The purpose of the present study was to evaluate the effectiveness of passive and post-exercise heat acclimation strategies through directly heating the skin with a water-perfused suit. Nineteen young males participated in the heat acclimation (HA) protocols for 10 days, which were conducted at an air temperature of 33oC with 60%RH. The exercise-only condition (N = 6) conducted 1-h treadmill walking (6 km·h-1) followed by 1-h rest. The post-exercise passive-heating condition (N = 6) wore the suit (inflow water temperature 44.2oC) for 1-h after 1-h walking. The passive-heating condition (N = 7) donned the suit for 2 h. Heat tolerance tests (leg immersion in 42oC water for 60 min) were conducted before and after the training to evaluate changes due to the 10-day intervention. Reflecting that suit-wearing for 10 days as both passive and post-exercise HA strategies can effectively induce adaptive changes, significant interaction effects appeared in: increase or decrease in mean skin temperature (P < 0.05) and elevation in whole-body sweat rate (P < 0.05). Reduction in rectal temperature (P < 0.05) and blood pressure (P < 0.05) were found most prominently in the passive-heating condition. These results indicate that this new method of heat acclimation training, donning a skin-heating water-perfused suit, can generate thermoregulatory benefits. The passive HA intervention could be applied to individuals for whom doing exercise regularly are not feasible.
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Affiliation(s)
- Yelin Ko
- College of Human Ecology, Seoul National University, South Korea
| | - Juho Kang
- College of Human Ecology, Seoul National University, South Korea; Department of Physical Education, Seoul National University, South Korea
| | - Seon-Hong Seol
- College of Human Ecology, Seoul National University, South Korea
| | - Joo-Young Lee
- College of Human Ecology, Seoul National University, South Korea; Research Institute of Human Ecology, Seoul National University, South Korea.
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Daanen H, Bose-O'Reilly S, Brearley M, Flouris DA, Gerrett NM, Huynen M, Jones HM, Lee JKW, Morris N, Norton I, Nybo L, Oppermann E, Shumake-Guillemot J, Van den Hazel P. COVID-19 and thermoregulation-related problems: Practical recommendations. Temperature (Austin) 2020; 8:1-11. [PMID: 33553500 PMCID: PMC7849778 DOI: 10.1080/23328940.2020.1790971] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The COVID-19 pandemic started in the cold months of the year 2020 in the Northern hemisphere. Concerns were raised that the hot season may lead to additional problems as some typical interventions to prevent heat-related illness could potentially conflict with precautions to reduce coronavirus transmission. Therefore, an international research team organized by the Global Health Heat Information Network generated an inventory of the specific concerns about this nexus and began to address the issues. Three key thermal and covid-19 related topics were highlighted: 1) For the general public, going to public cool areas in the hot season interferes with the recommendation to stay at home to reduce the spread of the virus. Conflicting advice makes it necessary to revise national heat plans and alert policymakers of this forecasted issue. 2) For medical personnel working in hot conditions, heat strain is exacerbated due to a reduction in heat loss from wearing personal protective equipment to prevent contamination. To avoid heat-related injuries, medical personnel are recommended to precool and to minimize the increase in body core temperature using adopted work/rest schedules, specific clothing systems, and by drinking cold fluids. 3) Fever, one of the main symptoms of COVID-19, may be difficult to distinguish from heat-induced hyperthermia and a resting period may be necessary prior to measurement to avoid misinterpretation. In summary, heat in combination with the COVID-19 pandemic leads to additional problems; the impact of which can be reduced by revising heat plans and implementing special measures attentive to these compound risks.
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Affiliation(s)
- Hein Daanen
- Department of Human Movement Sciences. Faculty of Behavioral and Movement Sciences. Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Stephan Bose-O'Reilly
- Institute and Clinic for Occupational, Social and Environmental Medicine, University Hospital, LMU Munich, Germany.,Institute for Public Health, Medical Decision Making and HTA, UMIT - Private University for Health Sciences, Medical Informatics and Technology, Hall i.T., Austria.,Hospital St. Hedwig of the Order of St. John, Institute and Clinic for Occupational, Social and Environmental Medicine, University Children's Hospital Regensburg (KUNO), University of Regensburg, Regensburg, Munich, Germany
| | - Matt Brearley
- National Critical Care and Trauma Response Centre, Australia
| | - D Andreas Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Greece
| | - Nicola M Gerrett
- Department of Human Movement Sciences. Faculty of Behavioral and Movement Sciences. Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Maud Huynen
- Maastricht University Institute (MSI), Maastricht University, Maastricht, The Netherlands
| | - Hunter M Jones
- University Corporation for Atmospheric Research in Service to the U.S. National Oceanic & Atmospheric Administration, Silver Spring, MD, USA
| | - Jason Kai Wei Lee
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Global Asia Institute, National University of Singapore, Singapore.,N.1 Institute for Health, National University of Singapore, Singapore
| | | | - Ian Norton
- Respond Global, Australia.,Previously World Health Organization, Switzerland
| | - Lars Nybo
- University of Copenhagen, Copenhagen, Denmark
| | - Elspeth Oppermann
- Department Für Geographie, Ludwig-Maximilians-Universität München, Germany
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Yanovich R, Ketko I, Charkoudian N. Sex Differences in Human Thermoregulation: Relevance for 2020 and Beyond. Physiology (Bethesda) 2020; 35:177-184. [PMID: 32293229 DOI: 10.1152/physiol.00035.2019] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The participation of women in physically strenuous athletic and occupational tasks has increased substantially in the past decade. Female sex steroids have influences on thermoregulatory processes that could impact physical performance in the heat. Here, we summarize and evaluate the current literature regarding sex differences in thermoregulation and provide recommendations for heat-illness risk-mitigation strategies.
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Affiliation(s)
- R Yanovich
- The Institute of Military Physiology, Israel Defense Forces, Medical Corps, Tel-Hashomer, Israel
- Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer, Israel
- Department of Military Medicine, Faculty of Medicine, Hebrew University, Jerusalem, Israel
- The Academic College at Wingate, Wingate Institute, Netanya, Israel
| | - I Ketko
- The Institute of Military Physiology, Israel Defense Forces, Medical Corps, Tel-Hashomer, Israel
- Heller Institute of Medical Research, Sheba Medical Center, Tel-Hashomer, Israel
| | - N Charkoudian
- U.S. Army Research Institute of Environmental Medicine, Natick, Massachussetts
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Garrett AT, Dodd E, Biddlecombe V, Gleadall-Siddall D, Burke R, Shaw J, Bray J, Jones H, Abt G, Gritt J. Effectiveness of Short-Term Heat Acclimation on Intermittent Sprint Performance With Moderately Trained Females Controlling for Menstrual Cycle Phase. Front Physiol 2019; 10:1458. [PMID: 31849708 PMCID: PMC6895212 DOI: 10.3389/fphys.2019.01458] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/12/2019] [Indexed: 11/13/2022] Open
Abstract
Introduction Investigate the effectiveness of short-term heat acclimation (STHA), over 5-days (permissive dehydration), on an intermittent sprint exercise protocol (HST) with females. Controlling for menstrual cycle phase. Materials and Methods Ten, moderately trained, females (Mean [SD]; age 22.6 [2.7] y; stature 165.3 [6.2] cm; body mass 61.5 [8.7] kg; V.O2peak 43.9 [8.6] mL⋅kg–1⋅min–1) participated. The HST (31.0°C; 50%RH) was 9 × 5 min (45-min) of intermittent exercise, based on exercise intensities of female soccer players, using a motorized treadmill and Wattbike. Participants completed HST1 vs. HST2 as a control (C) trial. Followed by 90 min, STHA (no fluid intake), for five consecutive days in 39.5°C; 60%RH, using controlled-hyperthermia (∼rectal temperature [Tre] 38.5°C). The HST3 occurred within 1 week after STHA. The HST2 vs HST3 trials were in the luteal phase, using self-reported menstrual questionnaire and plasma 17β-estradiol. Results Pre (HST2) vs post (HST3) STHA there was a reduction at 45-min in Tre by 0.20°C (95%CI −0.30 to −0.10°C; d = 0.77); T¯sk (−0.50; −0.90 to −0.10°C; d = 0.80); and T¯b (−0.25; −0.35 to −0.15°C; d = 0.92). Cardiac frequency reduced at 45-min (−8; −16 to −1 b⋅min–1; d = 1.11) and %PV increased (7.0; −0.4 to 14.5%: d = 1.27). Mean power output increased across all nine maximal sprints by 56W (−26 to 139W; d = 0.69; n = 9). There was limited difference (P > 0.05) for these measures in HST1 vs HST2 C trial. Discussion Short-term heat acclimation (5-days) using controlled-hyperthermia, leads to physiological adaptation during intermittent exercise in the heat, in moderately trained females when controlling for menstrual cycle phase.
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Affiliation(s)
- Andrew T Garrett
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Edward Dodd
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Victoria Biddlecombe
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Damien Gleadall-Siddall
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Rachel Burke
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Jake Shaw
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - James Bray
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Huw Jones
- Mathematics and Physical Science, Faculty of Science and Engineering, University of Hull, Hull, United Kingdom
| | - Grant Abt
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
| | - Jarrod Gritt
- Department of Sport, Health and Exercise Science, Faculty of Health Science, University of Hull, Hull, United Kingdom
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Gibson OR, James CA, Mee JA, Willmott AG, Turner G, Hayes M, Maxwell NS. Heat alleviation strategies for athletic performance: A review and practitioner guidelines. Temperature (Austin) 2019; 7:3-36. [PMID: 32166103 PMCID: PMC7053966 DOI: 10.1080/23328940.2019.1666624] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/06/2019] [Accepted: 09/08/2019] [Indexed: 12/19/2022] Open
Abstract
International competition inevitably presents logistical challenges for athletes. Events such as the Tokyo 2020 Olympic Games require further consideration given historical climate data suggest athletes will experience significant heat stress. Given the expected climate, athletes face major challenges to health and performance. With this in mind, heat alleviation strategies should be a fundamental consideration. This review provides a focused perspective of the relevant literature describing how practitioners can structure male and female athlete preparations for performance in hot, humid conditions. Whilst scientific literature commonly describes experimental work, with a primary focus on maximizing magnitudes of adaptive responses, this may sacrifice ecological validity, particularly for athletes whom must balance logistical considerations aligned with integrating environmental preparation around training, tapering and travel plans. Additionally, opportunities for sophisticated interventions may not be possible in the constrained environment of the athlete village or event arenas. This review therefore takes knowledge gained from robust experimental work, interprets it and provides direction on how practitioners/coaches can optimize their athletes' heat alleviation strategies. This review identifies two distinct heat alleviation themes that should be considered to form an individualized strategy for the athlete to enhance thermoregulatory/performance physiology. First, chronic heat alleviation techniques are outlined, these describe interventions such as heat acclimation, which are implemented pre, during and post-training to prepare for the increased heat stress. Second, acute heat alleviation techniques that are implemented immediately prior to, and sometimes during the event are discussed. Abbreviations: CWI: Cold water immersion; HA: Heat acclimation; HR: Heart rate; HSP: Heat shock protein; HWI: Hot water immersion; LTHA: Long-term heat acclimation; MTHA: Medium-term heat acclimation; ODHA: Once-daily heat acclimation; RH: Relative humidity; RPE: Rating of perceived exertion; STHA: Short-term heat acclimation; TCORE: Core temperature; TDHA: Twice-daily heat acclimation; TS: Thermal sensation; TSKIN: Skin temperature; V̇O2max: Maximal oxygen uptake; WGBT: Wet bulb globe temperature.
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Affiliation(s)
- Oliver R. Gibson
- Centre for Human Performance, Exercise and Rehabilitation (CHPER), Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, UK
| | - Carl A. James
- Institut Sukan Negara (National Sports Institute), Kuala Lumpur, Malaysia
| | - Jessica A. Mee
- School of Sport and Exercise Sciences, University of Worcester, Worcester, UK
| | - Ashley G.B. Willmott
- Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, Cambridge, UK
| | - Gareth Turner
- Bisham Abbey National High-Performance Centre, English Institute of Sport, EIS Performance Centre, Marlow, UK
| | - Mark Hayes
- Environmental Extremes Laboratory, School of Sport and Service Management, University of Brighton, Eastbourne, UK
| | - Neil S. Maxwell
- Environmental Extremes Laboratory, School of Sport and Service Management, University of Brighton, Eastbourne, UK
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