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Eifling KP, Gaudio FG, Dumke C, Lipman GS, Otten EM, Martin AD, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update. Wilderness Environ Med 2024; 35:112S-127S. [PMID: 38425235 DOI: 10.1177/10806032241227924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.
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Affiliation(s)
- Kurt P Eifling
- Department of Emergency Medicine, University of Arkansas for Medical Sciences, Fayetteville, AR
| | - Flavio G Gaudio
- Department of Emergency Medicine, New York-Presbyterian Hospital / Weill Cornell Medical College, New York, NY
| | - Charles Dumke
- School of Integrative Physiology and Athletic Training, University of Montana, Missoula, MT
| | | | - Edward M Otten
- Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH
| | - August D Martin
- Department of Internal Medicine, University of Arkansas for Medical Sciences, Fayetteville, AR
| | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT
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Flouris AD, Notley SR, Stearns RL, Casa DJ, Kenny GP. Recommended water immersion duration for the field treatment of exertional heat stroke when rectal temperature is unavailable. Eur J Appl Physiol 2024; 124:479-490. [PMID: 37552243 DOI: 10.1007/s00421-023-05290-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/14/2023] [Indexed: 08/09/2023]
Abstract
INTRODUCTION The recommended treatment for exertional heat stroke is immediate, whole-body immersion in < 10 °C water until rectal temperature (Tre) reaches ≤ 38.6 °C. However, real-time Tre assessment is not always feasible or available in field settings or emergency situations. We defined and validated immersion durations for water temperatures of 2-26 °C for treating exertional heat stroke. METHODS We compiled data for 54 men and 18 women from 7 previous laboratory studies and derived immersion durations for reaching 38.6 °C Tre. The resulting immersion durations were validated against the durations of cold-water immersion used to treat 162 (98 men; 64 women) exertional heat stroke cases at the Falmouth Road Race between 1984 and 2011. RESULTS Age, height, weight, body surface area, body fat, fat mass, lean body mass, and peak oxygen uptake were weakly associated with the cooling time to a safe Tre of 38.6 °C during immersions to 2-26 °C water (R2 range: 0.00-0.16). Using a specificity criterion of 0.9, receiver operating characteristics curve analysis showed that exertional heat stroke patients must be immersed for 11-12 min when water temperature is ≤ 9 °C, and for 18-19 min when water temperature is 10-26 °C (Cohen's Kappa: 0.32-0.75, p < 0.001; diagnostic odds ratio: 8.63-103.27). CONCLUSION The reported immersion durations are effective for > 90% of exertional heat stroke patients with pre-immersion Tre of 39.5-42.8 °C. When available, real-time Tre monitoring is the standard of care to accurately diagnose and treat exertional heat stroke, avoiding adverse health outcomes associated with under- or over-cooling, and for implementing cool-first transport second exertional heat stroke policies.
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Affiliation(s)
- Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
- Defence Science and Technology Group, Melbourne, VIC, Australia
| | - Rebecca L Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, USA
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada.
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON, Canada.
- Montpetit Hall, 125 University Private, Room 367, Ottawa, ON, K1N 6N5, Canada.
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Berger NJA, Best R, Best AW, Lane AM, Millet GY, Barwood M, Marcora S, Wilson P, Bearden S. Limits of Ultra: Towards an Interdisciplinary Understanding of Ultra-Endurance Running Performance. Sports Med 2024; 54:73-93. [PMID: 37751076 DOI: 10.1007/s40279-023-01936-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2023] [Indexed: 09/27/2023]
Abstract
Ultra-endurance running (UER) poses extreme mental and physical challenges that present many barriers to completion, let alone performance. Despite these challenges, participation in UER events continues to increase. With the relative paucity of research into UER training and racing compared with traditional endurance running distance (e.g., marathon), it follows that there are sizable improvements still to be made in UER if the limitations of the sport are sufficiently understood. The purpose of this review is to summarise our current understanding of the major limitations in UER. We begin with an evolutionary perspective that provides the critical background for understanding how our capacities, abilities and limitations have come to be. Although we show that humans display evolutionary adaptations that may bestow an advantage for covering large distances on a daily basis, these often far exceed the levels of our ancestors, which exposes relative limitations. From that framework, we explore the physiological and psychological systems required for running UER events. In each system, the factors that limit performance are highlighted and some guidance for practitioners and future research are shared. Examined systems include thermoregulation, oxygen delivery and utilisation, running economy and biomechanics, fatigue, the digestive system, nutritional and psychological strategies. We show that minimising the cost of running, damage to lower limb tissue and muscle fatigability may become crucial in UER events. Maintaining a sustainable core body temperature is critical to performance, and an even pacing strategy, strategic heat acclimation and individually calculated hydration all contribute to sustained performance. Gastrointestinal issues affect almost every UER participant and can be due to a variety of factors. We present nutritional strategies for different event lengths and types, such as personalised and evidence-based approaches for varying types of carbohydrate, protein and fat intake in fluid or solid form, and how to avoid flavour fatigue. Psychology plays a vital role in UER performance, and we highlight the need to be able to cope with complex situations, and that specific long and short-term goal setting improves performance. Fatigue in UER is multi-factorial, both physical and mental, and the perceived effort or level of fatigue have a major impact on the ability to continue at a given pace. Understanding the complex interplay of these limitations will help prepare UER competitors for the different scenarios they are likely to face. Therefore, this review takes an interdisciplinary approach to synthesising and illuminating limitations in UER performance to assist practitioners and scientists in making informed decisions in practice and applicable research.
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Affiliation(s)
- Nicolas J A Berger
- School of Health and Life Sciences, Teesside University, Middlesbrough, UK.
| | - Russ Best
- Centre for Sport Science and Human Performance, Wintec, Hamilton, New Zealand
| | - Andrew W Best
- Department of Biology, Massachusetts College of Liberal Arts, North Adams, MA, USA
| | - Andrew M Lane
- Faculty of Education Health and Wellbeing, University of Wolverhampton, Walsall, UK
| | - Guillaume Y Millet
- Univ Lyon, UJM Saint-Etienne, Inter-University Laboratory of Human Movement Biology, Saint Etienne, France
- Institut Universitaire de France (IUF), Paris, France
| | - Martin Barwood
- Department of Sport, Health and Nutrition, Leeds Trinity University Horsforth, Leeds, UK
| | - Samuele Marcora
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Patrick Wilson
- Department of Human Movement Sciences, Old Dominion University, Norfolk, VA, USA
| | - Shawn Bearden
- Department of Biological Sciences, Idaho State University, Pocatello, ID, USA
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise. Eur J Appl Physiol 2024; 124:1-145. [PMID: 37796292 DOI: 10.1007/s00421-023-05276-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 07/04/2023] [Indexed: 10/06/2023]
Abstract
In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Rehan M, Al-Bahadly I, Thomas DG, Young W, Cheng LK, Avci E. Smart capsules for sensing and sampling the gut: status, challenges and prospects. Gut 2023; 73:186-202. [PMID: 37734912 PMCID: PMC10715516 DOI: 10.1136/gutjnl-2023-329614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 08/26/2023] [Indexed: 09/23/2023]
Abstract
Smart capsules are developing at a tremendous pace with a promise to become effective clinical tools for the diagnosis and monitoring of gut health. This field emerged in the early 2000s with a successful translation of an endoscopic capsule from laboratory prototype to a commercially viable clinical device. Recently, this field has accelerated and expanded into various domains beyond imaging, including the measurement of gut physiological parameters such as temperature, pH, pressure and gas sensing, and the development of sampling devices for better insight into gut health. In this review, the status of smart capsules for sensing gut parameters is presented to provide a broad picture of these state-of-the-art devices while focusing on the technical and clinical challenges the devices need to overcome to realise their value in clinical settings. Smart capsules are developed to perform sensing operations throughout the length of the gut to better understand the body's response under various conditions. Furthermore, the prospects of such sensing devices are discussed that might help readers, especially health practitioners, to adapt to this inevitable transformation in healthcare. As a compliment to gut sensing smart capsules, significant amount of effort has been put into the development of robotic capsules to collect tissue biopsy and gut microbiota samples to perform in-depth analysis after capsule retrieval which will be a game changer for gut health diagnosis, and this advancement is also covered in this review. The expansion of smart capsules to robotic capsules for gut microbiota collection has opened new avenues for research with a great promise to revolutionise human health diagnosis, monitoring and intervention.
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Affiliation(s)
- Muhammad Rehan
- Department of Electronic Engineering, Sir Syed University of Engineering & Technology, Karachi, Pakistan
| | - Ibrahim Al-Bahadly
- Department of Mechanical and Electrical Engineering, Massey University, Palmerston North, New Zealand
| | - David G Thomas
- School of Agriculture and Environment, Massey University, Palmerston North, New Zealand
| | - Wayne Young
- AgResearch Ltd, Palmerston North, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Riddet Institute, Massey University, Palmerston North, New Zealand
| | - Ebubekir Avci
- Department of Mechanical and Electrical Engineering, Massey University, Palmerston North, New Zealand
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington, New Zealand
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 2: physiological measurements. Eur J Appl Physiol 2023; 123:2587-2685. [PMID: 37796291 DOI: 10.1007/s00421-023-05284-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 07/14/2023] [Indexed: 10/06/2023]
Abstract
In this, the second of four historical reviews on human thermoregulation during exercise, we examine the research techniques developed by our forebears. We emphasise calorimetry and thermometry, and measurements of vasomotor and sudomotor function. Since its first human use (1899), direct calorimetry has provided the foundation for modern respirometric methods for quantifying metabolic rate, and remains the most precise index of whole-body heat exchange and storage. Its alternative, biophysical modelling, relies upon many, often dubious assumptions. Thermometry, used for >300 y to assess deep-body temperatures, provides only an instantaneous snapshot of the thermal status of tissues in contact with any thermometer. Seemingly unbeknownst to some, thermal time delays at some surrogate sites preclude valid measurements during non-steady state conditions. To assess cutaneous blood flow, immersion plethysmography was introduced (1875), followed by strain-gauge plethysmography (1949) and then laser-Doppler velocimetry (1964). Those techniques allow only local flow measurements, which may not reflect whole-body blood flows. Sudomotor function has been estimated from body-mass losses since the 1600s, but using mass losses to assess evaporation rates requires precise measures of non-evaporated sweat, which are rarely obtained. Hygrometric methods provide data for local sweat rates, but not local evaporation rates, and most local sweat rates cannot be extrapolated to reflect whole-body sweating. The objective of these methodological overviews and critiques is to provide a deeper understanding of how modern measurement techniques were developed, their underlying assumptions, and the strengths and weaknesses of the measurements used for humans exercising and working in thermally challenging conditions.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- College of Human Ecology, Research Institute of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Hutchins KP, Minett GM, Stewart IB. Treating exertional heat stroke: Limited understanding of the female response to cold water immersion. Front Physiol 2022; 13:1055810. [PMID: 36505067 PMCID: PMC9732943 DOI: 10.3389/fphys.2022.1055810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/02/2022] [Indexed: 11/26/2022] Open
Abstract
According to an expansive body of research and best practice statements, whole-body cold water immersion is the gold standard treatment for exertional heat stroke. However, as this founding evidence was predominantly drawn from males, the current guidelines for treatment are being applied to women without validation. Given the recognised differences in thermal responses experienced by men and women, all-encompassing exertional heat stroke treatment advice may not effectively protect both sexes. In fact, recent evidence suggests that hyperthermic women cool faster than hyperthermic men during cold water immersion. This raises the question of whether overcooling is risked if the present guidelines are followed. The current mini-review examined the literature on women's response to cold water immersion as a treatment for exertional heat stroke and aimed to clarify whether the current guidelines have appropriately considered research investigating women. The potential implications of applying these guidelines to women were also discussed.
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Taylor NAS, Lee JY, Kim S, Notley SR. Physiological interactions with personal-protective clothing, physically demanding work and global warming: An Asia-Pacific perspective. J Therm Biol 2021; 97:102858. [PMID: 33863427 DOI: 10.1016/j.jtherbio.2021.102858] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 01/03/2023]
Abstract
The Asia-Pacific contains over half of the world's population, 21 countries have a Gross Domestic Product <25% of the world's largest economy, many countries have tropical climates and all suffer the impact of global warming. That 'perfect storm' exacerbates the risk of occupational heat illness, yet first responders must perform physically demanding work wearing personal-protective clothing and equipment. Unfortunately, the Eurocentric emphasis of past research has sometimes reduced its applicability to other ethnic groups. To redress that imbalance, relevant contemporary research has been reviewed, to which has been added information applicable to people of Asian, Melanesian and Polynesian ancestry. An epidemiological triad is used to identify the causal agents and host factors of work intolerance within hot-humid climates, commencing with the size dependency of resting metabolism and heat production accompanying load carriage, followed by a progression from the impact of single-layered clothing through to encapsulating ensembles. A morphological hypothesis is presented to account for inter-individual differences in heat production and heat loss, which seems to explain apparent ethnic- and gender-related differences in thermoregulation, at least within thermally compensable states. The mechanisms underlying work intolerance, cardiovascular insufficiency and heat illness are reviewed, along with epidemiological data from the Asia-Pacific. Finally, evidence-based preventative and treatment strategies are presented and updated concerning moisture-management fabrics and barriers, dehydration, pre- and post-exercise cooling, and heat adaptation. An extensive reference list is provided, with >25 recommendations enabling physiologists, occupational health specialists, policy makers, purchasing officers and manufacturers to rapidly extract interpretative outcomes pertinent to the Asia-Pacific.
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Affiliation(s)
- Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
| | - Joo-Young Lee
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea
| | - Siyeon Kim
- Human Convergence Technology R&D Department, Korea Institute of Industrial Technology, Ansan, Republic of Korea
| | - Sean R Notley
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
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Filep EM, Murata Y, Endres BD, Kim G, Stearns RL, Casa DJ. Exertional Heat Stroke, Modality Cooling Rate, and Survival Outcomes: A Systematic Review. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:E589. [PMID: 33167534 PMCID: PMC7694459 DOI: 10.3390/medicina56110589] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/15/2020] [Accepted: 10/27/2020] [Indexed: 12/20/2022]
Abstract
Background and Objectives: The purpose of this systematic review is to synthesize the influence cooling modality has on survival with and without medical complications from exertional heat stroke (EHS) in sport and military populations. Methods and Materials: All peer-reviewed case reports or series involving EHS patients were searched in the following online databases: PubMed, Scopus, SPORTDiscus, Medline, CINAHL, Academic Search Premier, and the Cochrane Library: Central Registry of Clinical Trials. Cooling methods were subdivided into "adequate" (>0.15 °C/min) versus "insufficient" (<0.15 °C/min) based on previously published literature on EHS cooling rates. Results: 613 articles were assessed for quality and inclusion in the review. Thirty-two case reports representing 521 EHS patients met the inclusion criteria. Four hundred ninety-eight (498) patients survived EHS (95.58%) and 23 (4.41%) patients succumbed to complications. Fischer's Exact test on 2 × 2 contingency tables and relative risk ratios were calculated to determine if modality cooling rate was associated with patient outcomes. EHS patients that survived who were cooled with an insufficient cooling rate had a 4.57 times risk of medical complications compared to patients who were treated by adequate cooling methods, regardless of setting (RR = 4.57 (95%CI: 3.42, 6.28)). Conclusions: This is the largest EHS dataset yet compiled that analyzes the influence of cooling rate on patient outcomes. Zero patients died (0/521, 0.00%) when treatment included a modality with an adequate cooling rate. Conversely, 23 patients died (23/521, 4.41%) with insufficient cooling. One hundred seventeen patients (117/521, 22.46%) survived with medical complications when treatment involved an insufficient cooling rate, whereas, only four patients had complications (4/521, 0.77%) despite adequate cooling. Cooling rates >0.15 °C/min for EHS patients were significantly associated with surviving EHS without medical complications. In order to provide the best standard of care for EHS patients, an aggressive cooling rate >0.15 °C/min can maximize survival without medical complications after exercise-induced hyperthermia.
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Affiliation(s)
- Erica M. Filep
- Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA; (B.D.E.); (G.K.); (R.L.S.); (D.J.C.)
| | - Yuki Murata
- Graduate School of Education and Human Development, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan;
| | - Brad D. Endres
- Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA; (B.D.E.); (G.K.); (R.L.S.); (D.J.C.)
| | - Gyujin Kim
- Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA; (B.D.E.); (G.K.); (R.L.S.); (D.J.C.)
| | - Rebecca L. Stearns
- Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA; (B.D.E.); (G.K.); (R.L.S.); (D.J.C.)
| | - Douglas J. Casa
- Korey Stringer Institute, University of Connecticut, Storrs, CT 06269-1110, USA; (B.D.E.); (G.K.); (R.L.S.); (D.J.C.)
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Singletary EM, Zideman DA, Bendall JC, Berry DA, Borra V, Carlson JN, Cassan P, Chang WT, Charlton NP, Djärv T, Douma MJ, Epstein JL, Hood NA, Markenson DS, Meyran D, Orkin A, Sakamoto T, Swain JM, Woodin JA, De Buck E, De Brier N, O D, Picard C, Goolsby C, Oliver E, Klaassen B, Poole K, Aves T, Lin S, Handley AJ, Jensen J, Allan KS, Lee CC. 2020 International Consensus on First Aid Science With Treatment Recommendations. Resuscitation 2020; 156:A240-A282. [PMID: 33098920 DOI: 10.1016/j.resuscitation.2020.09.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This is the summary publication of the International Liaison Committee on Resuscitation's 2020 International Consensus on First Aid Science With Treatment Recommendations. It addresses the most recent published evidence reviewed by the First Aid Task Force science experts. This summary addresses the topics of first aid methods of glucose administration for hypoglycemia; techniques for cooling of exertional hyperthermia and heatstroke; recognition of acute stroke; the use of supplementary oxygen in acute stroke; early or first aid use of aspirin for chest pain; control of life- threatening bleeding through the use of tourniquets, haemostatic dressings, direct pressure, or pressure devices; the use of a compression wrap for closed extremity joint injuries; and temporary storage of an avulsed tooth. Additional summaries of scoping reviews are presented for the use of a recovery position, recognition of a concussion, and 6 other first aid topics. The First Aid Task Force has assessed, discussed, and debated the certainty of evidence on the basis of Grading of Recommendations, Assessment, Development, and Evaluation criteria and present their consensus treatment recommendations with evidence-to-decision highlights and identified priority knowledge gaps for future research. The 2020 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) Science With Treatment Recommendations (CoSTR) is the fourth in a series of annual summary publications from the International Liaison Committee on Resuscitation (ILCOR). This 2020 CoSTR for first aid includes new topics addressed by systematic reviews performed within the past 12 months. It also includes updates of the first aid treatment recommendations published from 2010 through 2019 that are based on additional evidence evaluations and updates. As a result, this 2020 CoSTR for first aid represents the most comprehensive update since 2010.
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Singletary EM, Zideman DA, Bendall JC, Berry DC, Borra V, Carlson JN, Cassan P, Chang WT, Charlton NP, Djärv T, Douma MJ, Epstein JL, Hood NA, Markenson DS, Meyran D, Orkin AM, Sakamoto T, Swain JM, Woodin JA. 2020 International Consensus on First Aid Science With Treatment Recommendations. Circulation 2020; 142:S284-S334. [PMID: 33084394 DOI: 10.1161/cir.0000000000000897] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This is the summary publication of the International Liaison Committee on Resuscitation's 2020 International Consensus on First Aid Science With Treatment Recommendations. It addresses the most recent published evidence reviewed by the First Aid Task Force science experts. This summary addresses the topics of first aid methods of glucose administration for hypoglycemia; techniques for cooling of exertional hyperthermia and heatstroke; recognition of acute stroke; the use of supplementary oxygen in acute stroke; early or first aid use of aspirin for chest pain; control of life-threatening bleeding through the use of tourniquets, hemostatic dressings, direct pressure, or pressure devices; the use of a compression wrap for closed extremity joint injuries; and temporary storage of an avulsed tooth. Additional summaries of scoping reviews are presented for the use of a recovery position, recognition of a concussion, and 6 other first aid topics. The First Aid Task Force has assessed, discussed, and debated the certainty of evidence on the basis of Grading of Recommendations, Assessment, Development, and Evaluation criteria and present their consensus treatment recommendations with evidence-to-decision highlights and identified priority knowledge gaps for future research.
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Leyk D, Hoitz J, Becker C, Glitz KJ, Nestler K, Piekarski C. Health Risks and Interventions in Exertional Heat Stress. DEUTSCHES ARZTEBLATT INTERNATIONAL 2020; 116:537-544. [PMID: 31554541 DOI: 10.3238/arztebl.2019.0537] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 11/27/2022]
Abstract
BACKGROUND With climate change, heat waves are expected to become more frequent in the near future. Already, on average more than 25 000 "heat deaths" are estimated to occur in Europe every year. However, heat stress and heat illnesses arise not just when ambient temperatures are high. Physical exertion increases heat production within the organism many times over; if not enough heat is lost, there is a risk of exertional heat stress. This review article discusses contributing factors, at-risk groups, and the diagnosis and treatment of heat illnesses. METHODS A selective literature search was carried out on PubMed. Current guidelines and expert recommendations were also included. RESULTS Apart from muscular heat production (>70% of converted energy), there are other factors that singly or in combination can give rise to heat stress: clothing, climate/acclimatization, and individual factors. Through its insulating properties, clothing reduces the evaporation of sweat (the most effective physiological cooling mechanism). A sudden heat wave, or changing the climate zone (as with air travel), increases the risk of a heat-related health event. Overweight, low fitness level, acute infections, illness, dehydration, and other factors also reduce heat tolerance. In addition to children, older people are particularly at risk because of their reduced physiological adaptability, (multi-)morbidity, and intake of prescription drugs. A heat illness can progress suddenly to life-threatening heat stroke. Successful treatment depends on rapid diagnosis and cooling the body down as quickly as possible. The aim is to reduce core body temperature to <40 °C within 30 minutes. CONCLUSION Immediately effective cooling interventions are the only causal treatment for heat stroke. Time once lost cannot be made up. Prevention (acclimatization, reduced exposure, etc.) and terminating the heat stress in good time (e.g., stopping work) are better than any cure.
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Affiliation(s)
- Dieter Leyk
- Bundeswehr Institute for Preventive Medicine; German Sport University Cologne; Bundeswehr Hospital Hamburg; Department of Geriatrics and Geriatric Rehabilitation at the Robert-Bosch-Hospital Stuttgart; Bundeswehr Hospital Koblenz; Institute and Policlinic for Occupational Medicine, Environmental Medicine and Prevention Research, University of Cologne
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First aid cooling techniques for heat stroke and exertional hyperthermia: A systematic review and meta-analysis. Resuscitation 2020; 148:173-190. [PMID: 31981710 DOI: 10.1016/j.resuscitation.2020.01.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 01/02/2020] [Indexed: 01/29/2023]
Abstract
BACKGROUND Heat stroke is an emergent condition characterized by hyperthermia (>40 °C/>104 °F) and nervous system dysregulation. There are two primary etiologies: exertional which occurs during physical activity and non-exertional which occurs during extreme heat events without physical exertion. Left untreated, both may lead to significant morbidity, are considered a special circumstance for cardiac arrest, and cause of mortality. METHODS We searched Medline, Embase, CINAHL and SPORTDiscus. We used Grading of Recommendations Assessment, Development and Evaluation (GRADE) methods and risk of bias assessments to determine the certainty and quality of evidence. We included randomized controlled trials, non-randomized trials, cohort studies and case series of five or more patients that evaluated adults and children with non-exertional or exertional heat stroke or exertional hyperthermia, and any cooling technique applicable to first aid and prehospital settings. Outcomes included: cooling rate, mortality, neurological dysfunction, adverse effects and hospital length of stay. RESULTS We included 63 studies, of which 37 were controlled studies, two were cohort studies and 24 were case series of heat stroke patients. Water immersion of adults with exertional hyperthermia [cold water (14-17 °C/57.2-62.6 °F), colder water (8-12 °C/48.2-53.6 °F) and ice water (1-5 °C/33.8-41 °F)] resulted in faster cooling rates when compared to passive cooling. No single water temperature range was found to be associated with a quicker core temperature reduction than another (cold, colder or ice). CONCLUSION Water immersion techniques (using 1-17 °C water) more effectively lowered core body temperatures when compared with passive cooling, in hyperthermic adults. The available evidence suggests water immersion can rapidly reduce core body temperature in settings where it is feasible.
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Lipman GS, Gaudio FG, Eifling KP, Ellis MA, Otten EM, Grissom CK. Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2019 Update. Wilderness Environ Med 2019; 30:S33-S46. [DOI: 10.1016/j.wem.2018.10.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/04/2018] [Accepted: 10/22/2018] [Indexed: 10/26/2022]
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Choo HC, Peiffer JJ, Lopes-Silva JP, Mesquita RNO, Amano T, Kondo N, Abbiss CR. Effect of ice slushy ingestion and cold water immersion on thermoregulatory behavior. PLoS One 2019; 14:e0212966. [PMID: 30811512 PMCID: PMC6392407 DOI: 10.1371/journal.pone.0212966] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 02/12/2019] [Indexed: 11/18/2022] Open
Abstract
Two studies were conducted to examine the effects of ice slushy ingestion (ICE) and cold water immersion (CWI) on thermoregulatory and sweat responses during constant (study 1) and self-paced (study 2) exercise. In study 1, 11 men cycled at 40-50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity, RH). In study 2, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (33.9 ± 0.2°C and 42.5 ± 3.9%RH). In both studies, each trial was preceded by 30 min of CWI (~22°C), ICE or no cooling (CON). Rectal temperature (Tre), skin temperature (Tsk), thermal sensation, and sweat responses were measured. In study 1, ICE decreased Tre-Tsk gradient versus CON (p = 0.005) during first 5 min of exercise, while CWI increased Tre-Tsk gradient versus CON and ICE for up to 20 min during the exercise (p<0.05). In study 2, thermal sensation was lower in CWI versus CON and ICE for up to 35-40 min during the exercise (p<0.05). ICE reduced thermal sensation versus CON during the first 20 min of exercise (p<0.05). In study 2, CWI improved mean power output (MPO) by ~8 W, compared with CON only (p = 0.024). In both studies, CWI (p<0.001) and ICE (p = 0.019) delayed sweating by 1-5 min but did not change the body temperature sweating threshold, compared with CON (both p>0.05). Increased Tre-Tsk gradient by CWI improved MPO while ICE reduced Tre but did not confer any ergogenic effect. Both precooling treatments attenuated the thermal efferent signals until a specific body temperature threshold was reached.
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Affiliation(s)
- Hui C. Choo
- Centre for Exercise and Sports Science Research, School of Medical and
Health Sciences, Edith Cowan University, Joondalup, Western Australia,
Australia
- * E-mail:
| | - Jeremiah J. Peiffer
- School of Psychology and Exercise Science, Murdoch University, Murdoch,
Western, Australia, Australia
| | - João P. Lopes-Silva
- School of Physical Education and Sport, University of São Paulo (USP),
São Paulo, São Paulo, Brazil
| | - Ricardo N. O. Mesquita
- Centre for Exercise and Sports Science Research, School of Medical and
Health Sciences, Edith Cowan University, Joondalup, Western Australia,
Australia
| | - Tatsuro Amano
- Faculty of Education, Niigata University, Niigata, Niigata Prefecture,
Japan
| | - Narihiko Kondo
- Laboratory for Applied Human Physiology, Graduate School of Human
Development and Environment, Kobe University, Kobe, Hyōgo Prefecture,
Japan
| | - Chris R. Abbiss
- Centre for Exercise and Sports Science Research, School of Medical and
Health Sciences, Edith Cowan University, Joondalup, Western Australia,
Australia
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Poirier MP, Notley SR, Flouris AD, Kenny GP. Physical characteristics cannot be used to predict cooling time using cold-water immersion as a treatment for exertional hyperthermia. Appl Physiol Nutr Metab 2018. [PMID: 29529383 DOI: 10.1139/apnm-2017-0619] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined if physical characteristics could be used to predict cooling time during cold water immersion (CWI, 2 °C) following exertional hyperthermia (rectal temperature ≥39.5 °C) in a physically heterogeneous group of men and women (n = 62). Lean body mass was the only significant predictor of cooling time following CWI (R2 = 0.137; P < 0.001); however, that prediction did not provide the precision (mean residual square error: 3.18 ± 2.28 min) required to act as a safe alternative to rectal temperature measurements.
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Affiliation(s)
- Martin P Poirier
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Sean R Notley
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Andreas D Flouris
- b FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, 42100, Greece
| | - Glen P Kenny
- c Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,d Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.,e Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON K1Y 4E9, Canada
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Caldwell JN, van den Heuvel AMJ, Kerry P, Clark MJ, Peoples GE, Taylor NAS. A vascular mechanism to explain thermally mediated variations in deep-body cooling rates during the immersion of profoundly hyperthermic individuals. Exp Physiol 2018; 103:512-522. [DOI: 10.1113/ep086760] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/15/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Joanne N. Caldwell
- Centre for Human and Applied Physiology, School of Medicine; University of Wollongong; Wollongong NSW 2522 Australia
| | - Anne M. J. van den Heuvel
- Centre for Human and Applied Physiology, School of Medicine; University of Wollongong; Wollongong NSW 2522 Australia
| | - Pete Kerry
- Centre for Human and Applied Physiology, School of Medicine; University of Wollongong; Wollongong NSW 2522 Australia
| | - Mitchell J. Clark
- Centre for Human and Applied Physiology, School of Medicine; University of Wollongong; Wollongong NSW 2522 Australia
| | - Gregory E. Peoples
- Centre for Human and Applied Physiology, School of Medicine; University of Wollongong; Wollongong NSW 2522 Australia
| | - Nigel A. S. Taylor
- Centre for Human and Applied Physiology, School of Medicine; University of Wollongong; Wollongong NSW 2522 Australia
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Choo HC, Nosaka K, Peiffer JJ, Ihsan M, Abbiss CR. Ergogenic effects of precooling with cold water immersion and ice ingestion: A meta-analysis. Eur J Sport Sci 2017; 18:170-181. [DOI: 10.1080/17461391.2017.1405077] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Hui C. Choo
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Dr, Joondalup, WA, Australia
| | - Kazunori Nosaka
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Dr, Joondalup, WA, Australia
| | - Jeremiah J. Peiffer
- School of Psychology and Exercise Science, Murdoch University, 90 South St, Murdoch, WA, Australia
| | - Mohammed Ihsan
- Athlete Health and Performance Research Centre, ASPETAR – Qatar Orthopaedic and Sports Medicine Hospital, P.O. Box 29222, Doha, Qatar
| | - Chris R. Abbiss
- Centre for Exercise and Sports Science Research (CESSR), School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Dr, Joondalup, WA, Australia
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Miller KC, Hughes LE, Long BC, Adams WM, Casa DJ. Validity of Core Temperature Measurements at 3 Rectal Depths During Rest, Exercise, Cold-Water Immersion, and Recovery. J Athl Train 2017; 52:332-338. [PMID: 28207294 PMCID: PMC5402531 DOI: 10.4085/1062-6050-52.2.10] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT No evidence-based recommendation exists regarding how far clinicians should insert a rectal thermistor to obtain the most valid estimate of core temperature. Knowing the validity of temperatures at different rectal depths has implications for exertional heat-stroke (EHS) management. OBJECTIVE To determine whether rectal temperature (Trec) taken at 4 cm, 10 cm, or 15 cm from the anal sphincter provides the most valid estimate of core temperature (as determined by esophageal temperature [Teso]) during similar stressors an athlete with EHS may experience. DESIGN Cross-sectional study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Seventeen individuals (14 men, 3 women: age = 23 ± 2 years, mass = 79.7 ± 12.4 kg, height = 177.8 ± 9.8 cm, body fat = 9.4% ± 4.1%, body surface area = 1.97 ± 0.19 m2). INTERVENTION(S) Rectal temperatures taken at 4 cm, 10 cm, and 15 cm from the anal sphincter were compared with Teso during a 10-minute rest period; exercise until the participant's Teso reached 39.5°C; cold-water immersion (∼10°C) until all temperatures were ≤38°C; and a 30-minute postimmersion recovery period. The Teso and Trec were compared every minute during rest and recovery. Because exercise and cooling times varied, we compared temperatures at 10% intervals of total exercise and cooling durations for these periods. MAIN OUTCOME MEASURE(S) The Teso and Trec were used to calculate bias (ie, the difference in temperatures between sites). RESULTS Rectal depth affected bias (F2,24 = 6.8, P = .008). Bias at 4 cm (0.85°C ± 0.78°C) was higher than at 15 cm (0.65°C ± 0.68°C, P < .05) but not higher than at 10 cm (0.75°C ± 0.76°C, P > .05). Bias varied over time (F2,34 = 79.5, P < .001). Bias during rest (0.42°C ± 0.27°C), exercise (0.23°C ± 0.53°C), and recovery (0.65°C ± 0.35°C) was less than during cooling (1.72°C ± 0.65°C, P < .05). Bias during exercise was less than during postimmersion recovery (0.65°C ± 0.35°C, P < .05). CONCLUSIONS When EHS is suspected, clinicians should insert the flexible rectal thermistor to 15 cm (6 in) because it is the most valid depth. The low level of bias during exercise suggests Trec is valid for diagnosing hyperthermia. Rectal temperature is a better indicator of pelvic organ temperature during cold-water immersion than is Teso.
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Bierens JJLM, Lunetta P, Tipton M, Warner DS. Physiology Of Drowning: A Review. Physiology (Bethesda) 2017; 31:147-66. [PMID: 26889019 DOI: 10.1152/physiol.00002.2015] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.
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Affiliation(s)
| | - Philippe Lunetta
- Department of Pathology and Forensic Medicine, University of Turku, Turku, Finland
| | - Mike Tipton
- Department of Sport and Exercise Science, Extreme Environments Laboratory, University of Portsmouth, Portsmouth, United Kingdom; and
| | - David S Warner
- Departments of Anesthesiology, Neurobiology and Surgery, Duke University Medical Center, Durham, North Carolina
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Tan PMS, Teo EYN, Ali NB, Ang BCH, Iskandar I, Law LYL, Lee JKW. Evaluation of Various Cooling Systems After Exercise-Induced Hyperthermia. J Athl Train 2017; 52:108-116. [PMID: 28156130 DOI: 10.4085/1062-6050-52.1.11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Rapid diagnosis and expeditious cooling of individuals with exertional heat stroke is paramount for survival. OBJECTIVE To evaluate the efficacy of various cooling systems after exercise-induced hyperthermia. DESIGN Crossover study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty-two men (age = 24 ± 2 years, height = 1.76 ± 0.07 m, mass = 70.7 ± 9.5 kg) participated. INTERVENTION(S) Each participant completed a treadmill walk until body core temperature reached 39.50°C. The treadmill walk was performed at 5.3 km/h on an 8.5% incline for 50 minutes and then at 5.0 km/h until the end of exercise. Each participant experienced 4 cooling phases in a randomized, repeated-crossover design: (1) no cooling (CON), (2) body-cooling unit (BCU), (3) EMCOOLS Flex.Pad (EC), and (4) ThermoSuit (TS). Cooling continued for 30 minutes or until body core temperature reached 38.00°C, whichever occurred earlier. MAIN OUTCOME MEASURE(S) Body core temperature (obtained via an ingestible telemetric temperature sensor) and heart rate were measured continuously during the exercise and cooling phases. Rating of perceived exertion was monitored every 5 minutes during the exercise phase and thermal sensation every minute during the cooling phase. RESULTS The absolute cooling rate was greatest with TS (0.16°C/min ± 0.06°C/min) followed by EC (0.12°C/min ± 0.04°C/min), BCU (0.09°C/min ± 0.06°C/min), and CON (0.06°C/min ± 0.02°C/min; P < .001). The TS offered a greater cooling rate than all other cooling modalities in this study, whereas EC offered a greater cooling rate than both CON and BCU (P < .0083 for all). Effect-size calculations, however, showed that EC and BCU were not clinically different. CONCLUSION These findings provide objective evidence for selecting the most effective cooling system of those we evaluated for cooling individuals with exercise-induced hyperthermia. Nevertheless, factors other than cooling efficacy need to be considered when selecting an appropriate cooling system.
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Affiliation(s)
- Pearl M S Tan
- Combat Protection and Performance, Defence Medical and Environmental Research Institute, Singapore
| | - Eunice Y N Teo
- Combat Protection and Performance, Defence Medical and Environmental Research Institute, Singapore
| | | | - Bryan C H Ang
- Soldier Performance Centre, Singapore Armed Forces.,National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore
| | | | - Lydia Y L Law
- Combat Protection and Performance, Defence Medical and Environmental Research Institute, Singapore
| | - Jason K W Lee
- Combat Protection and Performance, Defence Medical and Environmental Research Institute, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
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Butts CL, McDermott BP, Buening BJ, Bonacci JA, Ganio MS, Adams JD, Tucker MA, Kavouras SA. Physiologic and Perceptual Responses to Cold-Shower Cooling After Exercise-Induced Hyperthermia. J Athl Train 2016; 51:252-7. [PMID: 26942657 DOI: 10.4085/1062-6050-51.4.01] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Exercise conducted in hot, humid environments increases the risk for exertional heat stroke (EHS). The current recommended treatment of EHS is cold-water immersion; however, limitations may require the use of alternative resources such as a cold shower (CS) or dousing with a hose to cool EHS patients. OBJECTIVE To investigate the cooling effectiveness of a CS after exercise-induced hyperthermia. DESIGN Randomized, crossover controlled study. SETTING Environmental chamber (temperature = 33.4°C ± 2.1°C; relative humidity = 27.1% ± 1.4%). PATIENTS OR OTHER PARTICIPANTS Seventeen participants (10 male, 7 female; height = 1.75 ± 0.07 m, body mass = 70.4 ± 8.7 kg, body surface area = 1.85 ± 0.13 m(2), age range = 19-35 years) volunteered. INTERVENTION(S) On 2 occasions, participants completed matched-intensity volitional exercise on an ergometer or treadmill to elevate rectal temperature to ≥39°C or until participant fatigue prevented continuation (reaching at least 38.5°C). They were then either treated with a CS (20.8°C ± 0.80°C) or seated in the chamber (control [CON] condition) for 15 minutes. MAIN OUTCOME MEASURE(S) Rectal temperature, calculated cooling rate, heart rate, and perceptual measures (thermal sensation and perceived muscle pain). RESULTS The rectal temperature (P = .98), heart rate (P = .85), thermal sensation (P = .69), and muscle pain (P = .31) were not different during exercise for the CS and CON trials (P > .05). Overall, the cooling rate was faster during CS (0.07°C/min ± 0.03°C/min) than during CON (0.04°C/min ± 0.03°C/min; t16 = 2.77, P = .01). Heart-rate changes were greater during CS (45 ± 20 beats per minute) compared with CON (27 ± 10 beats per minute; t16 = 3.32, P = .004). Thermal sensation was reduced to a greater extent with CS than with CON (F3,45 = 41.12, P < .001). CONCLUSIONS Although the CS facilitated cooling rates faster than no treatment, clinicians should continue to advocate for accepted cooling modalities and use CS only if no other validated means of cooling are available.
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Affiliation(s)
| | | | | | | | | | - J D Adams
- University of Arkansas, Fayetteville
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Effects of mild hypohydration on cooling during cold-water immersion following exertional hyperthermia. Eur J Appl Physiol 2016; 116:687-95. [DOI: 10.1007/s00421-016-3329-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/05/2016] [Indexed: 10/22/2022]
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Friesen BJ, Carter MR, Poirier MP, Kenny GP. Water immersion in the treatment of exertional hyperthermia: physical determinants. Med Sci Sports Exerc 2015; 46:1727-35. [PMID: 24784433 DOI: 10.1249/mss.0000000000000292] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE We examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (CWI, 2°C) and temperate water immersion (TWI, 26°C) after exercise-induced hyperthermia. METHODS Twenty male participants were divided into two groups: high (315.6 ± 7.9 cm·kg, n = 10) and low (275.6 ± 8.6 cm·kg, n = 10) AD/LBM. On two separate occasions, participants ran on a treadmill in the heat (40.0°C, 20% relative humidity) wearing an impermeable rain suit until rectal temperature reached 40.0°C. After exercise, participants were immersed up to the nipples (arms remained out of the water) in either a CWI (2°C) or a TWI (26°C) circulated water bath until rectal temperature returned to 37.5°C. RESULTS Overall rectal cooling rates were significantly different between experimental groups (high vs low AD/LBM, P = 0.005) and between immersion conditions (CWI vs TWI, P < 0.001). Individuals with a high AD/LBM had an approximately 1.7-fold greater overall rectal cooling rate relative to those with low AD/LBM during both CWI (high: 0.27°C·min ± 0.10°C·min vs low: 0.16°C·min ± 0.10°C·min) and TWI (high: 0.10°C·min ± 0.05°C·min vs low: 0.06°C·min ± 0.02°C·min). Further, the overall rectal cooling rates during CWI were approximately 2.7-fold greater than during TWI for both the high (CWI: 0.27°C·min ± 0.10°C·min vs TWI: 0.10°C·min ± 0.05°C·min) and the low (CWI: 0.16°C·min ± 0.10°C·min vs TWI: 0.06°C·min ± 0.02°C·min) AD/LBM groups. CONCLUSION We show that individuals with a low AD/LBM have a reduced rectal cooling rate and take longer to cool than those with a high AD/LBM during both CWI and TWI. However, CWI provides the most effective cooling treatment irrespective of physical differences.
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Affiliation(s)
- Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, CANADA
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Lipman GS, Eifling KP, Ellis MA, Gaudio FG, Otten EM, Grissom CK. Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness: 2014 update. Wilderness Environ Med 2015; 25:S55-65. [PMID: 25498263 DOI: 10.1016/j.wem.2014.07.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 06/26/2014] [Accepted: 07/01/2014] [Indexed: 11/29/2022]
Abstract
The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best practice recommendations for both field and hospital-based therapeutic management of heat illness. These recommendations are graded on the basis of the quality of supporting evidence, and balance between the benefits and risks or burdens for each modality. This is an updated version of the original WMS Practice Guidelines for the Prevention and Treatment of Heat-Related Illness published in Wilderness & Environmental Medicine 2013;24(4):351-361.
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Affiliation(s)
- Grant S Lipman
- Division of Emergency Medicine, Stanford University School of Medicine, Stanford, CA (Dr Lipman).
| | - Kurt P Eifling
- Division of Emergency Medicine, Barnes-Jewish Hospital/Washington University School of Medicine, Saint Louis, MO (Dr Eifling)
| | - Mark A Ellis
- Department of Emergency Medicine, Spartanburg Regional Healthcare System, Spartanburg, SC (Dr Eifling)
| | - Flavio G Gaudio
- Division of Emergency Medicine, New York-Presbyterian Hospital/Weill Cornell Medical College, New York, NY (Dr Gaudio)
| | - Edward M Otten
- Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH (Dr Otten)
| | - Colin K Grissom
- Pulmonary and Critical Care Division, Intermountain Medical Center and the University of Utah, Salt Lake City, UT (Dr Grissom)
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Flouris AD, Friesen BJ, Carlson MJ, Casa DJ, Kenny GP. Effectiveness of cold water immersion for treating exertional heat stress when immediate response is not possible. Scand J Med Sci Sports 2015; 25 Suppl 1:229-39. [DOI: 10.1111/sms.12317] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2014] [Indexed: 11/28/2022]
Affiliation(s)
- A. D. Flouris
- FAME Laboratory; Department of Physical Education and Sport Science; University of Thessaly; Trikala Greece
| | - B. J. Friesen
- Human Environmental Physiological Research Unit; University of Ottawa; Ottawa Ontario Canada
| | - M. J. Carlson
- Human Environmental Physiological Research Unit; University of Ottawa; Ottawa Ontario Canada
| | - D. J. Casa
- Korey Stringer Institute; University of Connecticut; Storrs Connecticut USA
| | - G. P. Kenny
- Human Environmental Physiological Research Unit; University of Ottawa; Ottawa Ontario Canada
- Korey Stringer Institute; University of Connecticut; Storrs Connecticut USA
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Abstract
AbstractExertional heat illness is a classification of disease with clinical presentations that are not always diagnosed easily. Exertional heat stroke is a significant cause of death in competitive sports, and the increasing popularity of marathons races and ultra-endurance competitions will make treating many heat illnesses more common for Emergency Medical Services (EMS) providers. Although evidence is available primarily from case series and healthy volunteer studies, the consensus for treating exertional heat illness, coupled with altered mental status, is whole body rapid cooling. Cold or ice water immersion remains the most effective treatment to achieve this goal. External thermometry is unreliable in the context of heat stress and direct internal temperature measurement by rectal or esophageal probes must be used when diagnosing heat illness and during cooling. With rapid recognition and implementation of effective cooling, most patients suffering from exertional heat stroke will recover quickly and can be discharged home with instructions to rest and to avoid heat stress and exercise for a minimum of 48 hours; although, further research pertaining to return to activity is warranted.PryorRR,RothRN,SuyamaJ,HostlerD.Exertional heat illness: emerging concepts and advances in prehospital care.Prehosp Disaster Med.2015;30(3):19.
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Cheung SS. Responses of the hands and feet to cold exposure. Temperature (Austin) 2015; 2:105-20. [PMID: 27227009 PMCID: PMC4843861 DOI: 10.1080/23328940.2015.1008890] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 01/09/2015] [Accepted: 01/09/2015] [Indexed: 11/19/2022] Open
Abstract
An initial response to whole-body or local exposure of the extremities to cold is a strong vasoconstriction, leading to a rapid decrease in hand and foot temperature. This impairs tactile sensitivity, manual dexterity, and muscle contractile characteristics while increasing pain and sympathetic drive, decreasing gross motor function, occupational performance, and survival. A paradoxical and cyclical vasodilatation often occurs in the fingers, toes, and face, and this has been termed the hunting response or cold-induced vasodilatation (CIVD). Despite being described almost a century ago, the mechanisms of CIVD are still disputed; research in this area has remained largely descriptive in nature. Recent research into CIVD has brought increased standardization of methodology along with new knowledge about the impact of mediating factors such as hypoxia and physical fitness. Increasing mechanistic analysis of CIVD has also emerged along with improved modeling and prediction of CIVD responses. The present review will survey work conducted during this century on CIVD, its potential mechanisms and modeling, and also the broader context of manual function in cold conditions.
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Affiliation(s)
- Stephen S Cheung
- Environmental Ergonomics Laboratory; Department of Kinesiology ; Brock University; St. Catharines , Canada
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Lipman GS, Eifling KP, Ellis MA, Gaudio FG, Otten EM, Grissom CK. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Heat-Related Illness. Wilderness Environ Med 2013; 24:351-61. [DOI: 10.1016/j.wem.2013.07.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 07/09/2013] [Accepted: 07/09/2013] [Indexed: 11/16/2022]
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Cooling and performance recovery of trained athletes: a meta-analytical review. Int J Sports Physiol Perform 2013; 8:227-42. [PMID: 23434565 DOI: 10.1123/ijspp.8.3.227] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE Cooling after exercise has been investigated as a method to improve recovery during intensive training or competition periods. As many studies have included untrained subjects, the transfer of those results to trained athletes is questionable. METHODS Therefore, the authors conducted a literature search and located 21 peer-reviewed randomized controlled trials addressing the effects of cooling on performance recovery in trained athletes. RESULTS For all studies, the effect of cooling on performance was determined and effect sizes (Hedges' g) were calculated. Regarding performance measurement, the largest average effect size was found for sprint performance (2.6%, g = 0.69), while for endurance parameters (2.6%, g = 0.19), jump (3.0%, g = 0.15), and strength (1.8%, g = 0.10), effect sizes were smaller. The effects were most pronounced when performance was evaluated 96 h after exercise (4.3%, g = 1.03). Regarding the exercise used to induce fatigue, effects after endurance training (2.4%, g = 0.35) were larger than after strength-based exercise (2.4%, g = 0.11). Cold-water immersion (2.9%, g = 0.34) and cryogenic chambers (3.8%, g = 0.25) seem to be more beneficial with respect to performance than cooling packs (-1.4%, g= -0.07). For cold-water application, whole-body immersion (5.1%, g = 0.62) was significantly more effective than immersing only the legs or arms (1.1%, g = 0.10). CONCLUSIONS In summary, the average effects of cooling on recovery of trained athletes were rather small (2.4%, g = 0.28). However, under appropriate conditions (whole-body cooling, recovery from sprint exercise), postexercise cooling seems to have positive effects that are large enough to be relevant for competitive athletes.
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Abstract
The increasing popularity of mass participation endurance events necessitates that on-site medical teams be well versed in the management of both common and life-threatening conditions. Exertional heat stroke is one such condition, which if left untreated can be fatal.
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Teunissen LPJ, de Haan A, de Koning JJ, Daanen HAM. Telemetry pill versus rectal and esophageal temperature during extreme rates of exercise-induced core temperature change. Physiol Meas 2012; 33:915-24. [PMID: 22551669 DOI: 10.1088/0967-3334/33/6/915] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Core temperature measurement with an ingestible telemetry pill has been scarcely investigated during extreme rates of temperature change, induced by short high-intensity exercise in the heat. Therefore, nine participants performed a protocol of rest, (sub)maximal cycling and recovery at 30 °C. The pill temperature (T(pill)) was compared with the rectal temperature (T(re)) and esophageal temperature (T(es)). T(pill) corresponded well to T(re) during the entire trial, but deviated considerably from T(es) during the exercise and recovery periods. During maximal exercise, the average ΔT(pill)-T(re) and ΔT(pill)-T(es) were 0.13 ± 0.26 and -0.57 ± 0.53 °C, respectively. The response time from the start of exercise, the rate of change during exercise and the peak temperature were similar for T(pill) and T(re.) T(es) responded 5 min earlier, increased more than twice as fast and its peak value was 0.42 ± 0.46 °C higher than T(pill). In conclusion, also during considerable temperature changes at a very high rate, T(pill) is still a representative of T(re). The extent of the deviation in the pattern and peak values between T(pill) and T(es) (up to >1 °C) strengthens the assumption that T(pill) is unsuited to evaluate central blood temperature when body temperatures change rapidly.
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Affiliation(s)
- L P J Teunissen
- Training and Performance Innovations,Soesterberg, The Netherlands.
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Weng Y, Sun S. Therapeutic hypothermia after cardiac arrest in adults: mechanism of neuroprotection, phases of hypothermia, and methods of cooling. Crit Care Clin 2011; 28:231-43. [PMID: 22433485 DOI: 10.1016/j.ccc.2011.10.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Yinlun Weng
- The Weil Institute of Critical Care Medicine, Rancho Mirage, CA 92270, USA
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Gagnon D, Kenny GP. Experimental evidence is available for safe cooling limits from exertional heat stroke. Eur J Appl Physiol 2011; 112:2783-4. [PMID: 22119957 DOI: 10.1007/s00421-011-2252-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Accepted: 11/15/2011] [Indexed: 10/15/2022]
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DeMartini JK, Ranalli GF, Casa DJ, Lopez RM, Ganio MS, Stearns RL, McDermott BP, Armstrong LE, Maresh CM. Comparison of Body Cooling Methods on Physiological and Perceptual Measures of Mildly Hyperthermic Athletes. J Strength Cond Res 2011; 25:2065-74. [DOI: 10.1519/jsc.0b013e3182259b1d] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gagnon D, Lemire BB, Casa DJ, Kenny GP. Cold-water immersion and the treatment of hyperthermia: using 38.6°C as a safe rectal temperature cooling limit. J Athl Train 2011; 45:439-44. [PMID: 20831387 DOI: 10.4085/1062-6050-45.5.439] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Cold-water immersion is recommended for the immediate field treatment of exertional heat stroke. However, concerns exist over potential overcooling of hyperthermic individuals during cold-water immersion. OBJECTIVE To evaluate the recommendation that removing previously hyperthermic individuals from a cold-water bath at a rectal temperature (T(re)) of 38.6°C would attenuate overcooling. DESIGN Controlled laboratory study. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS Participants included 6 men and 4 women (age = 22 ± 3 years, height = 172 ± 10 cm, mass = 67.8 ± 10.7 kg, body fat percentage = 17.1% ± 4.5%, maximum oxygen consumption = 59.3 ± 8.7 mL·kg(-1)·min(-1)). INTERVENTION(S) After exercising at an ambient temperature of 40.0°C for 38.5 ± 9.4 minutes, until T(re) reached 39.5°C, participants were immersed in a 2.0°C circulated water bath until T(re) decreased to either 37.5°C or 38.6°C. Subsequently, participants were removed from the water bath and recovered for 20 minutes at an ambient temperature of 25°C. MAIN OUTCOME MEASURE(S) Rectal and esophageal temperatures were measured continuously during the immersion and recovery periods. RESULTS Because of the experimental design, the overall time of immersion was greater during the 37.5°C trial (16.6 ± 5.7 minutes) than the 38.6°C trial (8.8 ± 2.6 minutes) (t(9) = -4.740, P = .001). During the recovery period after cold-water immersion, both rectal (F(1,9) = 50.540, P < .001) and esophageal (F(1,6) = 20.365, P = .007) temperatures remained greater in the 38.6°C trial than in the 37.5°C trial. This was evidenced by low points of 36.47°C ± 0.70°C and 37.19°C ± 0.71°C for rectal temperature (t(9) = 2.975, P = .016) and of 35.67°C ± 1.27°C and 36.72°C ± 0.95°C for esophageal temperature (t(6) = 3.963, P = .007) during the recovery period of the 37.5°C and 38.6°C trials, respectively. CONCLUSIONS Immersion for approximately 9 minutes to a rectal temperature cooling limit of 38.6°C negated any risk associated with overcooling hyperthermic individuals when they were immersed in 2°C water.
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Affiliation(s)
- Daniel Gagnon
- Human and Environmental Physiology Research Unit, University of Ottawa, ON, Canada
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Heart rate variability and baroreceptor sensitivity following exercise-induced hyperthermia in endurance trained men. Eur J Appl Physiol 2011; 112:501-11. [PMID: 21584685 DOI: 10.1007/s00421-011-1989-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
We evaluated the effect of exercise-induced hyperthermia (EIH) on autonomic nervous system (ANS) function in the early (<80 min) and late (24 and 48 h) stages of recovery. Eight males underwent three repeated 6 min 70° head-up tilts (HUT1, HUT2 and HUT3), each separated by 10-min supine rest in a non-exercise/non-heat stress control state (NHS). On a separate day, three 6 min 70° HUT were performed following EIH (esophageal temperature ≥ 40°C) and repeated after 24 and 48 h of recovery. Heart rate, stroke volume (SV), mean arterial pressure and cardiac output ([Formula: see text]) were evaluated during the last min prior to a change in posture. Responses to 70° HUT were compared to the same challenge performed without prior exercise and under a NHS condition. Relative to NHS, [Formula: see text] was maintained during the repeated HUT's following EIH, despite significant reductions in SV and sustained elevations in esophageal temperature (p < 0.05). The preserved [Formula: see text] appears to be due to increased HR (HUT1: NRS = 76 ± 3 beats min(-1), EIH = 126 ± 6 beats min(-1)) stemming from modulation of the ANS toward sympathetic dominance. Parasympathetic withdrawal was evidenced by a reduction in root mean squared successive difference (i.e., HUT1: NHS = 66 ± 12 ms, EIH = 9 ± 1 ms) of heart rate variability and paralleled by a reduction in baroreceptor sensitivity for all HUT's following EIH (p < 0.05). Despite significant modulation in ANS activity, Q is maintained and participants do not become orthostatic intolerant/syncopal during the short-term recovery period following EIH. Normal ANS and cardiovascular function is restored following 24 h of recovery.
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Makranz C, Heled Y, Moran DS. Hypothermia following exertional heat stroke treatment. Eur J Appl Physiol 2011; 111:2359-62. [DOI: 10.1007/s00421-011-1863-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 02/01/2011] [Indexed: 11/29/2022]
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Effect of contrast water therapy duration on recovery of cycling performance: a dose-response study. Eur J Appl Physiol 2010; 111:37-46. [PMID: 20809231 DOI: 10.1007/s00421-010-1614-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2010] [Indexed: 10/19/2022]
Abstract
This study investigated whether contrast water therapy (CWT) has a dose-response effect on recovery from high-intensity cycling. Eleven trained male cyclists completed four trials, each commencing with a 75-min cycling protocol containing six sets of five 15-s sprints and three 5-min time-trials in thermoneutral conditions. Ten minutes post-exercise, participants performed one of four recovery protocols: CWT for 6 min (CWT6), 12 min (CWT12), or 18 min (CWT18) duration, or a seated rest control trial. The CWT commenced in hot water (38.4 ± 0.6°C) and alternated between hot and cold water (14.6 ± 0.3°C) every minute with a 5-s changeover. The cycling protocol was repeated 2 h after completion of exercise bout one. Prior to exercise bout two, core temperature was lower in CWT12 (-0.19 ± 0.14°C, mean ± 90% CL) and CWT18 (-0.21 ± 0.10°C) than control. Compared with control, CWT6 substantially improved time-trial (1.5 ± 2.1%) and sprint performance (3.0 ± 3.1%), and CWT12 substantially improved sprint total work (4.3 ± 3.4%) and peak power (2.7 ± 3.8%) in exercise bout two. All CWT conditions generally improved thermal sensation, whole body fatigue and muscle soreness compared with control, but no differences existed between conditions in heart rate or rating of perceived exertion. In conclusion, CWT duration did not have a dose-response effect on recovery from high-intensity cycling; however, CWT for up to 12 min assisted recovery of cycling performance.
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Gagnon D, Lemire BB, Jay O, Kenny GP. Aural canal, esophageal, and rectal temperatures during exertional heat stress and the subsequent recovery period. J Athl Train 2010; 45:157-63. [PMID: 20210619 DOI: 10.4085/1062-6050-45.2.157] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT The measurement of body temperature is crucial for the initial diagnosis of exertional heat injury and for monitoring purposes during a subsequent treatment strategy. However, little information is available about how different measurements of body temperature respond during and after exertional heat stress. OBJECTIVE To present the temporal responses of aural canal (T(ac)), esophageal (T(es)), and rectal (T(re)) temperatures during 2 different scenarios (S1, S2) involving exertional heat stress and a subsequent recovery period. DESIGN Randomized controlled trial. SETTING University research laboratory. PATIENTS OR OTHER PARTICIPANTS Twenty-four healthy volunteers, with 12 (5 men, 7 women) participating in S1 and 12 (7 men, 5 women) participating in S2. INTERVENTION(S) The participants exercised in the heat (42 degrees C, 30% relative humidity) until they reached a 39.5 degrees C cut-off criterion, which was determined by T(re) in S1 and by T(es) in S2. As such, participants attained different levels of hyperthermia (as determined by T(re)) at the end of exercise. Participants in S1 were subsequently immersed in cold water (2 degrees C) until T(re) reached 37.5 degrees C, and participants in S2 recovered in a temperate environment (30 degrees C, 30% relative humidity) for 60 minutes. MAIN OUTCOME MEASURE(S) We measured T(ac), T(es), and T(re) throughout both scenarios. RESULTS The T(es) (S1 = 40.19 +/- 0.41 degrees C, S2 = 39.50 +/- 0.02 degrees C) was higher at the end of exercise compared with both T(ac) (S1 = 39.74 +/- 0.42 degrees C, S2 = 38.89 +/- 0.32 degrees C) and T(re) (S1 = 39.41 +/- 0.04 degrees C, S2 = 38.74 +/- 0.28 degrees C) (for both comparisons in each scenario, P < .001). Conversely, T(es) (S1 = 36.26 +/- 0.74 degrees C, S2 = 37.36 +/- 0.34 degrees C) and T(ac) (S1 = 36.48 +/- 1.07 degrees C, S2 = 36.97 +/- 0.38 degrees C) were lower compared with T(re) (S1 = 37.54 +/- 0.04 degrees C, S2 = 37.78 +/- 0.31 degrees C) at the end of both scenarios (for both comparisons in each scenario, P < .001). CONCLUSIONS We found that T(ac), T(es), and T(re) presented different temporal responses during and after both scenarios of exertional heat stress and a subsequent recovery period. Although these results may not have direct practical implications in the field monitoring and treatment of individuals with exertional heat injury, they do quantify the extent to which these body temperature measurements differ in such scenarios.
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Affiliation(s)
- Daniel Gagnon
- School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
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Sinclair WH, Rudzki SJ, Leicht AS, Fogarty AL, Winter SK, Patterson MJ. Efficacy of field treatments to reduce body core temperature in hyperthermic subjects. Med Sci Sports Exerc 2010; 41:1984-90. [PMID: 19812521 DOI: 10.1249/mss.0b013e3181a7ae82] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE To contrast the effects of three postcooling techniques in reducing body core temperature (Tc) in exercise-induced hyperthermic participants on the cessation of exercise. METHODS Eleven healthy active male volunteers were cooled during a 40-min period using three different methods: ice packs to the neck, axillae, and groin (ICE); water spray and fan (FAN); and 2 L of chilled (20 degrees C) intravenous saline administered during a 20-min period (IV). Rate of decrease in Tc, cardiovascular responses, and any incidence of reported adverse effects were investigated. Trials were presented in a counterbalanced order with the volunteers' body core temperature being elevated to 40.0 degrees C on three occasions via an intermittent walk-run (2 min at 6 km x h and 4 min at 10 km x h) protocol conducted within a climate-controlled chamber (34.2 +/- 0.5 degrees C and 62.3 +/- 3.1% relative humidity). RESULTS Rate of Tc reduction during the first 20 min of cooling was greater for FAN compared with ICE (0.09 +/- 0.02 degrees C.min vs 0.07 +/- 0.02 degrees C.min, P < 0.05), whereas IV did not differ with the other trials (0.08 +/- 0.01 degrees C.min, P > 0.05). Three participants complained of numbness or paresthesia in their arm or hand during administration of the chilled saline, although these symptoms resolved within 5 min of ceasing the infusion. CONCLUSIONS All three cooling techniques reduced Tc and would be suitable for first aid application in a field setting during transportation to adequate medical facilities. Chilled IV saline did not produce any contraindications, providing a suitable alternative for Tc cooling.
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Affiliation(s)
- Wade H Sinclair
- Institute of Sport and Exercise Science, James Cook University, Townsville, Queensland, Australia.
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Viveiros JDP, Meyer F, Kruel LFM. Imersão em água fria para o manejo da hipertermia severa. REV BRAS MED ESPORTE 2009. [DOI: 10.1590/s1517-86922009000500016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A incapacidade de dissipar o calor gerado pela atividade muscular prejudica o desempenho e aumenta a predisposição a lesões do organismo. A hipertermia severa induzida pelo esforço físico (HTE) prejudica a saúde e está associada à morbidade e mortalidade de indivíduos em diferentes atividades ocupacionais e atléticas. Estudos sobre a eficiência de métodos de resfriamento corporal têm recomendado a imersão em água fria para o tratamento da HTE. Sua utilização nos minutos iniciais pós-hipertemia parece a melhor recomendação por reduzir o tempo no qual a temperatura central permanece elevada. A manutenção de infraestrutura necessária para a realização desse procedimento deve ser considerada em atividades físicas e condições ambientais nas quais os indivíduos estão mais suscetíveis ao acometimento da HTE. As taxas de resfriamento observadas através da imersão em água a diferentes temperaturas podem servir de referência para o controle da duração do procedimento. Esta revisão analisa a recomendação da imersão em água fria como procedimento de resfriamento corporal para o manejo da HTE.
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Affiliation(s)
- Kenneth R. Diller
- Department of Biomedical Engineering, The University of Texas, Austin, Texas 78712;
| | - Liang Zhu
- Department of Mechanical Engineering, The University of Maryland, Baltimore, Maryland 21250
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Taylor NAS, Caldwell JN, Van den Heuvel AMJ, Patterson MJ. To cool, but not too cool: that is the question--immersion cooling for hyperthermia. Med Sci Sports Exerc 2009; 40:1962-9. [PMID: 18845977 DOI: 10.1249/mss.0b013e31817eee9d] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Patient cooling time can impact upon the prognosis of heat illness. Although ice-cold-water immersion will rapidly extract heat, access to ice or cold water may be limited in hot climates. Indeed, some have concerns regarding the sudden cold-water immersion of hyperthermic individuals, whereas others believe that cutaneous vasoconstriction may reduce convective heat transfer from the core. It was hypothesized that warmer immersion temperatures, which induce less powerful vasoconstriction, may still facilitate rapid cooling in hyperthermic individuals. METHODS Eight males participated in three trials and were heated to an esophageal temperature of 39.5 degrees C by exercising in the heat (36 degrees C, 50% relative humidity) while wearing a water-perfusion garment (40 degrees C). Subjects were cooled using each of the following methods: air (20-22 degrees C), cold-water immersion (14 degrees C), and temperate-water immersion (26 degrees C). RESULTS The time to reach an esophageal temperature of 37.5 degrees C averaged 22.81 min (air), 2.16 min (cold), and 2.91 min (temperate). Whereas each of the between-trial comparisons was statistically significant (P < 0.05), cooling in temperate water took only marginally longer than that in cold water, and one cannot imagine that the 45-s cooling time difference would have any meaningful physiological or clinical implications. CONCLUSION It is assumed that this rapid heat loss was due to a less powerful peripheral vasoconstrictor response, with central heat being more rapidly transported to the skin surface for dissipation. Although the core-to-water thermal gradient was much smaller with temperate-water cooling, greater skin and deeper tissue blood flows would support a superior convective heat delivery. Thus, a sustained physiological mechanism (blood flow) appears to have countered a less powerful thermal gradient, resulting in clinically insignificant differences in heat extraction between the cold and temperate cooling trials.
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Affiliation(s)
- Nigel A S Taylor
- Human Performance Laboratories, School of Health Sciences, University of Wollongong, Wollongong, Australia.
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Taylor NAS, Caldwell JN, van den Heuvel AMJ, Patterson MJ. RESPONSE. Med Sci Sports Exerc 2009. [DOI: 10.1249/mss.0b013e31819c7026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Zhang Y, Bishop PA, Casaru C, Davis JK. A new hand-cooling device to enhance firefighter heat strain recovery. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2009; 6:283-288. [PMID: 19242856 DOI: 10.1080/15459620902790277] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This study tested a new portable cooling device for fire fighting recovery. Participants (N = 8) walked and did arm curls (time-weighted VO(2): 1.6 L x min(-1) on a treadmill for 40 min in a heated chamber (wet bulb globe temperature: 33.7 degrees C; relative humidity: 40-45%) while wearing firefighter turn-out gear and self-contained breathing apparatus (SCBA). Immediately on finishing exercise, participants recovered for 40 min with either a hand-cooling device or seated passive recovery at an ambient temperature of 22 degrees C, 35% RH in a repeated-measures counterbalanced design. The cooling device had little impact on recovery during the first 30 min; however, compared with passive cooling, the cooling device resulted in significantly lower rectal temperature (T(re)) during the last 10 min. Relative to starting T(re) of the recovery period, Delta T(re) at 35 min had fallen 0.51 +/- 0.19 degrees C (passive) and 0.76 +/- 0.30 degrees C (active) (p = 0.03); and at 40 min Delta T(re) had fallen 0.63 +/- 0.17 degrees C (passive) and 0.88 +/- 0.31 degrees C (active) (p = 0.03). Cooling capacity of the device calculated from Delta T(re) over the whole recovery period averaged about 144% of passive. Reductions in heat storage enhance worker safety and performance in hot environments.
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Affiliation(s)
- Yang Zhang
- Human Performance Laboratory, University of Alabama, Tuscaloosa, Alabama 35487, USA.
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Physiological responses to cold water immersion following cycling in the heat. Int J Sports Physiol Perform 2009; 3:331-46. [PMID: 19211945 DOI: 10.1123/ijspp.3.3.331] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED Cold water immersion (CWI) has become a popular means of enhancing recovery from various forms of exercise. However, there is minimal scientific information on the physiological effects of CWI following cycling in the heat. PURPOSE To examine the safety and acute thermoregulatory, cardiovascular, metabolic, endocrine, and inflammatory responses to CWI following cycling in the heat. METHODS Eleven male endurance trained cyclists completed two simulated approximately 40-min time trials at 34.3 +/- 1.1 degrees C. All subjects completed both a CWI trial (11.5 degrees C for 60 s repeated three times) and a control condition (CONT; passive recovery in 24.2 +/- 1.8 degrees C) in a randomized cross-over design. Capillary blood samples were assayed for lactate, glucose, pH, and blood gases. Venous blood samples were assayed for catecholamines, cortisol, testosterone, creatine kinase, C-reactive protein, IL-6, and IGF-1 on 7 of the 11 subjects. Heart rate (HR), rectal (Tre), and skin temperatures (Tsk) were measured throughout recovery. RESULTS CWI elicited a significantly lower HR (CWI: Delta 116 +/- 9 bpm vs. CONT: Delta 106 +/- 4 bpm; P = .02), Tre (CWI: Delta 1.99 +/- 0.50 degrees C vs. CONT: Delta 1.49 +/- 0.50 degrees C; P = .01) and Tsk. However, all other measures were not significantly different between conditions. All participants subjectively reported enhanced sensations of recovery following CWI. CONCLUSION CWI did not result in hypothermia and can be considered safe following high intensity cycling in the heat, using the above protocol. CWI significantly reduced heart rate and core temperature; however, all other metabolic and endocrine markers were not affected by CWI.
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Therapeutic hypothermia with a novel surface cooling device improves neurologic outcome after prolonged cardiac arrest in swine*. Crit Care Med 2008; 36:895-902. [DOI: 10.1097/ccm.0b013e318165fb33] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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50
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Severe Hyperthermia in a 65-year-old Man Following Sustained Environmental Heat Exposure. J Emerg Nurs 2007; 33:550-2. [DOI: 10.1016/j.jen.2007.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 01/29/2007] [Accepted: 02/05/2007] [Indexed: 11/18/2022]
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