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Anderson SA, Eichner ER, Bennett S, Boden BP, Colgate B, Courson R, Davis JK, Elkins GA, Judge LW, Krueger M, Kucera KL, Niehoff K, Rooks Y, Tucker JB, Roberts WO. Preventing Exertional Heat Stroke in Football: Time for a Paradigm Shift. Sports Health 2024:19417381241260045. [PMID: 38874455 DOI: 10.1177/19417381241260045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024] Open
Abstract
CONTEXT Among American sports, football has the highest incidence of exertional heat stroke (EHS), despite decades of prevention strategies. Based on recent reports, 100% of high school and college EHS football fatalities occur during conditioning sessions. Linemen are the at-risk population, constituting 97% of football EHS deaths. Linemen heat up faster and cool down slower than other players. EVIDENCE ACQUISITION Case series were identified from organized, supervised football at the youth, high school, and collegiate levels and compiled in the National Registry of Catastrophic Sports Injuries. Sources for event occurrence were media reports and newspaper clippings, autopsy reports, certificates of death, school-sponsored investigations, and published medical literature. Articles were identified through PubMed with search terms "football," "exertional heat stroke," and "prevention." STUDY DESIGN Clinical review. LEVEL OF EVIDENCE Level 5. RESULTS Football EHS is tied to (1) high-intensity drills and conditioning that is not specific to individual player positions, (2) physical exertion as punishment; (3) failure to modify physical activity for high heat and humidity, (4) failure to recognize early signs and symptoms of EHS, and (5) death when cooling is delayed. CONCLUSION To prevent football EHS, (1) all training and conditioning should be position specific; (2) physical activity should be modified per the heat load; (3) understand that some players have a "do-or-die" mentality that supersedes their personal safety; (4) never use physical exertion as punishment; (5) eliminate conditioning tests, serial sprints, and any reckless drills that are inappropriate for linemen; and (6) consider air-conditioned venues for linemen during hot practices. To prevent EHS, train linemen based on game demands. STRENGTH-OF-RECOMMENDATION TAXONOMY n/a.
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Affiliation(s)
| | - E Randy Eichner
- Oklahoma University Health Science Center, Oklahoma City, Oklahoma
| | - Scott Bennett
- Collegiate Strength and Conditioning Coaches Association, Roanoke, Virginia
| | - Barry P Boden
- The Orthopaedic Center, a Division of CAO, Uniformed Services University, Rockville, Maryland
| | - Bob Colgate
- National Federation of State High School Associations [NFHS], Indianapolis, Indiana
| | - Ron Courson
- University of Georgia Athletic Association, Athens, Georgia
| | - Jon K Davis
- Gatorade Sports Science Institute, Frisco, Texas
| | | | | | - Mike Krueger
- Colorado High School Activities Association, Aurora, Colorado
| | - Kristen L Kucera
- Department of Exercise and Sport Science, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, and National Center for Catastrophic Sport Injury Research [NCCSIR], Chapel Hill, North Carolina
| | | | - Yvette Rooks
- University of Maryland-College Park, College Park, Maryland
| | - James B Tucker
- Syracuse University, Syracuse, New York, Department of Family Medicine, SUNY Upstate Medical University, Syracuse, New York, and St. Joseph's Hospital Health Center, Syracuse, New York
| | - William O Roberts
- American College of Sports Medicine, Indianapolis, Indiana, and Department of Family Medicine and Community Health, University of Minnesota, Minneapolis, Minnesota
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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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Henningsen K, Mika A, Alcock R, Gaskell SK, Parr A, Rauch C, Russo I, Snipe RMJ, Costa RJS. The increase in core body temperature in response to exertional-heat stress can predict exercise-induced gastrointestinal syndrome. Temperature (Austin) 2023; 11:72-91. [PMID: 38577295 PMCID: PMC10989703 DOI: 10.1080/23328940.2023.2213625] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/09/2023] [Indexed: 04/06/2024] Open
Abstract
Utilizing metadata from existing exertional and exertional-heat stress studies, the study aimed to determine if the exercise-associated increase in core body temperature can predict the change in exercise-induced gastrointestinal syndrome (EIGS) biomarkers and exercise-associated gastrointestinal symptoms (Ex-GIS). Endurance-trained individuals completed 2 h of running exercise in temperate (21.2-30.0°C) to hot (35.0-37.2°C) ambient conditions (n = 132 trials). Blood samples were collected pre- and post-exercise to determine the change in gastrointestinal integrity biomarkers and systemic inflammatory cytokines. Physiological and thermoregulatory strain variables were assessed every 10-15 min during exercise. The strength of the linear relationship between maximal (M-Tre) and change (Δ Tre) in rectal temperature and EIGS variables was determined via Spearman's rank correlation coefficients. While the strength of prediction was determined via simple and multiple linear regression analyses dependent on screened EIGS and Ex-GIS confounding factors. Significant positive correlations between Tre maximum (M-Tre) and change (Δ Tre) with I-FABP (rs = 0.434, p < 0.001; and rs = 0.305, p < 0.001; respectively), sCD14 (rs = 0.358, p < 0.001; and rs = 0.362, p < 0.001), systemic inflammatory response profile (SIR-Profile) (p < 0.001), and total Ex-GIS (p < 0.05) were observed. M-Tre and Δ Tre significantly predicted (adjusted R2) magnitude of change in I-FABP (R2(2,123)=0.164, p < 0.001; and R2(2,119)=0.058, p = 0.011; respectively), sCD14 (R2(2,81)=0.249, p < 0.001; and R2(2,77)=0.214, p < 0.001), SIR-Profile (p < 0.001), and total Ex-GIS (p < 0.05). Strong to weak correlations were observed between M-Tre and Δ Tre with plasma concentrations of I-FABP, sCD14, SIR-Profile, and Ex-GIS in response to exercise. M-Tre and Δ Tre can predict the magnitude of these EIGS variables and Ex-GIS in response to exercise.
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Affiliation(s)
- Kayla Henningsen
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
| | - Alice Mika
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
| | - Rebekah Alcock
- Department of Dietetics and Human Nutrition, La Trobe University, Bundoora, Victoria, Australia
| | - Stephanie K. Gaskell
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
| | - Alexandra Parr
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
| | - Christopher Rauch
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
| | - Isabela Russo
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
| | - Rhiannon M. J. Snipe
- Centre for Sport Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Australia
| | - Ricardo J. S. Costa
- Department of Nutrition, Dietetics and Food, Monash University, Victoria, Australia
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Yeargin S, Hirschhorn R, Grundstein A, Arango D, Graham A, Krebs A, Turner S. Variations of wet-bulb globe temperature across high school athletics in South Carolina. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023; 67:735-744. [PMID: 37002402 DOI: 10.1007/s00484-023-02449-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 02/24/2023] [Accepted: 02/28/2023] [Indexed: 05/09/2023]
Abstract
The purpose was to describe wet bulb globe temperature (WBGT) throughout a high school fall athletic season (August to November) after a state-wide mandate requiring schools to use a WBGT-guided activity modification table with categories (AMTC). A cross-sectional research design utilized 30 South Carolina high schools. The independent variables were region (upstate, midlands, and coastal), sport (football, tennis, cross-country), month, start times (7-10 am, 10 am-3 pm, 3-6 pm, and 6-9 pm), and event type (practice, competition). Dependent variables were event frequency, average WBGT, and AMTC. Practice WBGT was 78.7 ± 8.2 °F (range: 34.7 to 99.0 °F). A significant difference for WBGT across month (F6, 904.7 = 385.07, P < 0.001) existed, with early September hotter than all other months (84.8 °F ± 3.8, P < 0.001). Every month had practices in each AMTC, until early November. Most events (64.6%, n = 1986) did not change AMTC; however, 9.1% (n = 281) changed to a hotter category. The 10 am-3 pm start time was significantly hotter than all other time frames (83.0 °F ± 7.2, P < 0.05). Tennis experienced hotter practices (79.9 °F ± 6.9) than football (78.4 °F ± 8.5; P < 0.001) and cross country (78.2 °F ± 8.8, P < 0.001). Schools in the Midlands experienced hotter practices (80.1 °F ± 7.8) than upstate (P < 0.001) and coastal schools (P = 0.005). Competition WBGT was significantly cooler than practices (72.3 ± 10.5 °F, t = 12.04, P < 0.001) and differed across sports (F2, 20.78 = 18.39, P < .001). Both cross-country (P = 0.003) and tennis (P < 0.001) were hotter than football. Schools should continuously monitor WBGT throughout practices and until November to optimize AMTC use. Risk mitigation strategies are needed for sports other than football to decrease the risk of exertional heat illnesses.
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Affiliation(s)
- Susan Yeargin
- Exercise Science Department, University of South Carolina, Columbia, SC, USA.
| | - Rebecca Hirschhorn
- School of Kinesiology, Louisana State University, Baton Rouge, Louisana, USA
| | | | - Dylan Arango
- Exercise Science Department, University of South Carolina, Columbia, SC, USA
| | - Adam Graham
- Exercise Science Department, University of South Carolina, Columbia, SC, USA
| | - Amy Krebs
- Exercise Science Department, University of South Carolina, Columbia, SC, USA
| | - Sydney Turner
- Exercise Science Department, University of South Carolina, Columbia, SC, USA
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Abstract
Heat tolerance testing (HTT) has been developed to assess readiness for work or exercise in the heat based on thermoregulation during exertion. Although the Israeli Defense Forces protocol has been the most widely used and referenced, other protocols and variables considered in the interpretation of the testing are emerging. Our purpose was to summarize the role of HTT after exertional heat stroke; assess the validity of HTT; and provide a review of best-practice recommendations to guide clinicians, coaches, and researchers in the performance, interpretation, and future direction of HTT. We also offer the strength of evidence for these recommendations using the Strength of Recommendation Taxonomy system.
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Affiliation(s)
- Cody Butler
- Special Warfare Human Performance Squadron, Lackland Air Force Base, Texas
| | | | - Michelle Bruneau
- Sports Optimization and Rehabilitation Laboratory, Department of Kinesiology, University of Connecticut, Storrs
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Périard JD, DeGroot D, Jay O. Exertional heat stroke in sport and the military: epidemiology and mitigation. Exp Physiol 2022; 107:1111-1121. [PMID: 36039024 PMCID: PMC9826288 DOI: 10.1113/ep090686] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/12/2022] [Indexed: 01/11/2023]
Abstract
NEW FINDINGS What is the topic of this review? Exertional heat stroke epidemiology in sport and military settings, along with common risk factors and strategies and policies designed to mitigate its occurrence. What advances does it highlight? Individual susceptibility to exertional heat stroke risk is dependent on the interaction of intrinsic and extrinsic factors. Heat policies in sport should assess environmental conditions, as well as the characteristics of the athlete, clothing/equipment worn and activity level of the sport. Exertional heat stroke risk reduction in the military should account for factors specific to training and personnel. ABSTRACT Exertional heat illness occurs along a continuum, developing from the relatively mild condition of muscle cramps, to heat exhaustion, and in some cases to the life-threatening condition of heat stroke. The development of exertional heat stroke (EHS) is associated with an increase in core temperature stemming from inadequate heat dissipation to offset the rate of metabolically generated heat. Susceptibility to EHS is linked to the interaction of several factors including environmental conditions, individual characteristics, health conditions, medication and drug use, behavioural responses, and sport/organisational requirements. Two settings in which EHS is commonly observed are competitive sport and the military. In sport, the exact prevalence of EHS is unclear due to inconsistent exertional heat illness terminology, diagnostic criteria and data reporting. In contrast, exertional heat illness surveillance in the military is facilitated by standardised case definitions, a requirement to report all heat illness cases and a centralised medical record repository. To mitigate EHS risk, several strategies can be implemented by athletes and military personnel, including heat acclimation, ensuring adequate hydration, cold-water immersion and mandated work-to-rest ratios. Organisations may also consider developing sport or military task-specific heat stress policies that account for the evaporative heat loss requirement of participants, relative to the evaporative capacity of the environment. This review examines the epidemiology of EHS along with the strategies and policies designed to reduce its occurrence in sport and military settings. We highlight the nuances of identifying individuals at risk of EHS and summarise the benefits and shortcomings of various mitigation strategies.
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Affiliation(s)
- Julien D. Périard
- Research Institute for Sport and ExerciseUniversity of CanberraCanberraAustralia
| | - David DeGroot
- Army Heat CenterMartin Army Community HospitalFort BenningGAUSA
| | - Ollie Jay
- Thermal Ergonomics LaboratoryHeat and Health Research IncubatorFaculty of Medicine and HealthUniversity of SydneyCamperdownAustralia
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7
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Incidence, risk factors, characteristics and prognosis of exertional heat stroke and heat exhaustion in Reunion Island, 2014–2018: A retrospective multicentre study. Sci Sports 2022. [DOI: 10.1016/j.scispo.2021.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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8
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Klous L, van Diemen F, Ruijs S, Gerrett N, Daanen H, de Weerd M, Veenstra B, Levels K. Efficiency of three cooling methods for hyperthermic military personnel linked to water availability. APPLIED ERGONOMICS 2022; 102:103700. [PMID: 35231652 DOI: 10.1016/j.apergo.2022.103700] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 01/16/2022] [Accepted: 01/24/2022] [Indexed: 06/14/2023]
Abstract
PURPOSE Three feasible cooling methods for treatment of hyperthermic individuals in the military, that differed considerably in water volume needed (none to ~80 L), were evaluated. METHODS Ten male soldiers were cooled following exercise-induced hyperthermia (rectal temperature (Tre) ∼39.5 °C) using ventilation by fanning (1.7 m s-1), ventilation by fanning (1.7 m s-1) while wearing a wet t-shirt (250 mL-27 °C water) and tarp assisted cooling with oscillations (80 L of 27.2 ± 0.5 °C water; TACO). RESULTS Cooling rates were higher using TACO (0.116 ± 0.032 °C min-1) compared to ventilation (0.065 ± 0.011 °C min-1, P<0.001) and ventilation in combination with a wet t-shirt (0.074 ± 0.020 °C min-1, P=0.002). Time to cool (TTC) to Tre=38.2 °C for TACO was shorter (14 ± 4 min) compared to ventilation only (20 ± 5 min; P=0.018), but not to ventilation while wearing a wet t-shirt (18 ± 6 min; P=0.090). CONCLUSIONS TACO may be an acceptable, efficient and feasible cooling method in case of exertional heat stroke. However, in case of limited water availability, transportat should be prioritized, and cooling of any form should be implemented while waiting for and during transport.
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Affiliation(s)
- Lisa Klous
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands; Netherlands Organization for Applied Scientific Research (TNO), Department of Human Performance, Unit Defence, Safety and Security, Soesterberg, The Netherlands
| | - Femke van Diemen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands
| | - Silke Ruijs
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands
| | - Nicola Gerrett
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands; Gentherm Inc., Michigan, USA
| | - Hein Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, the Netherlands
| | - Marijne de Weerd
- Institute of Training Medicine and Training Physiology, TGTF, Royal Netherlands Army, the Netherlands
| | - Bertil Veenstra
- Institute of Training Medicine and Training Physiology, TGTF, Royal Netherlands Army, the Netherlands
| | - Koen Levels
- Institute of Training Medicine and Training Physiology, TGTF, Royal Netherlands Army, the Netherlands.
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9
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DeGroot DW, O'Connor FG, Roberts WO. Exertional heat stroke: An evidence based approach to clinical assessment and management. Exp Physiol 2022; 107:1172-1183. [PMID: 35771080 DOI: 10.1113/ep090488] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 06/06/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? The treatment of exertional heat stress, from initial field care through the return-to-activity decision, is reviewed. What advances does it highlight? Clinical assessment during field care using AVPU and vital signs to gauge recovery Approaches to field cooling and end of active cooling Shared clinical decision making for return to activity recommendations ABSTRACT: Exertional heat stroke (EHS) is a potentially fatal condition characterized by central nervous system dysfunction and body temperature often but not always >40°C that occurs in the context of physical work in warm or hot environments. In this paper, we review the continuum of care, from initial recognition and field care to transport and hospital care, and finally return to duty considerations. Morbidity and mortality can be greatly reduced if not eliminated with prompt recognition and aggressive cooling. If medical personnel are not present at point of collapse during or immediately following exercise, EHS should be the presumptive diagnosis until a formal diagnosis can be determined by qualified medical staff. EHS is the rare medical situation where initial treatment (cooling) takes precedence over transport to a medical facility, where advanced medical care may be required for severe EHS casualties. Recovery from EHS and return to activity is usually straightforward and unremarkable provided the casualty is rapidly cooled at time of collapse and adequate time is allowed for body healing. However, evidence-based data to guide return to activity following EHS is limited. Current research suggests that most individuals recover completely within a few weeks though some individuals may suffer prolonged sequalae and additional evaluation may be warranted, including heat tolerance testing. Several aspects of the care of the EHS casualty are based on best practices derived from personal experience and continued research is necessary to optimize evaluation and management. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Francis G O'Connor
- Department of Military and Emergency Medicine, Uniformed Services University, Bethesda, MD, USA
| | - William O Roberts
- Department of Family Medicine and Community Health, University of Minnesota Medical School, Minneapolis, MN, USA
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Garrett B, Lopez RM, Szymanski MR, Eidt D. Proper Recognition and Management of Exertional Heat Stroke in a High School Cross-Country Runner: A Validation Clinical Case Report. J Athl Train 2022; 57:586-591. [PMID: 35969664 DOI: 10.4085/1062-6050-0462.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A 14-year-old female high school cross- country runner (height = 154 cm, mass = 48.1 kg) with no history of exertional heat stroke (EHS) collapsed at the end of a race. An athletic trainer assessed the patient, who presented with difficulty breathing and then other signs of EHS (eg, confusion and agitation). The patient was taken to the medical area and draped with a towel, and a rectal temperature (Tre) of 106.9°F (41.6°C) was obtained. The emergency action plan was activated, and emergency medical services was called. The patient was submerged in a cold-water immersion tub until emergency medical services arrived (∼15 minutes; Tre = 100.1°F; cooling rate: 0.41°F.min-1[0.25°C.min-1]). At the hospital, the patient received intravenous fluids, and urine and blood tests were normal. She was not admitted and returned to running without sequelae. Following best practices, secondary school athletic trainers can prevent deaths from EHS by properly recognizing the condition and providing rapid cooling before transport.
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Affiliation(s)
- Bryanna Garrett
- School of Physical Therapy & Rehabilitation Sciences; Department of Orthopaedics & Sports Medicine; Morsani College of Medicine, University of South Florida, Tampa
| | - Rebecca M Lopez
- School of Physical Therapy & Rehabilitation Sciences; Department of Orthopaedics & Sports Medicine; Morsani College of Medicine, University of South Florida, Tampa
| | | | - Drew Eidt
- School of Physical Therapy & Rehabilitation Sciences; Department of Orthopaedics & Sports Medicine; Morsani College of Medicine, University of South Florida, Tampa
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11
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Caldwell AR, Saillant MM, Pitsas D, Johnson A, Bradbury KE, Charkoudian N. The Effectiveness of a Standardized Ice-Sheet Cooling Method Following Exertional Hyperthermia. Mil Med 2022; 187:e1017-e1023. [PMID: 35294018 DOI: 10.1093/milmed/usac047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/26/2022] [Accepted: 02/14/2022] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION Exertional heat illnesses remain a major threat to military service members in the United States and around the world. Exertional heat stroke (EHS) is the most severe heat illness, characterized by core hyperthermia and central nervous system dysfunction. Per current Army regulations, iced-sheet cooling (ISC) is the recommended immediate treatment for heat casualties in the field, but concerns have been raised regarding the efficacy of this approach. Thus, the purpose of this study was to quantify the cooling rate of ISC following exertional hyperthermia. MATERIALS AND METHODS We utilized a randomized crossover design with 2 experimental trials. In both trials, exertional hyperthermia was induced by walking (3.5 mph at 5% grade) on a treadmill in an environmental chamber (40 °C, 30% RH) for up to 3 hours or until core body temperature reached 39.2 °C. After the walking portion, individuals either received ISC (experimental trial) or cooling and rested supine in the same environmental conditions for 30 minutes with no ISC (control trial). For ISC, bed sheets soaked in ice water were applied (per Army guidance) at the neck, chest, and groin with another sheet covering the body. Sheets were rotated and resoaked every 3 minutes until core temperature decreased to <38.0 °C. RESULTS By design, participants finished exercise with increased core temperature (38.8 ± 0.39 °C vs. 38.90 ± 0.34 °C, ISC and control trials, P = 1.00). The ISC trial provided significantly (P = .023) greater cooling rates, 0.068 °C/min 95% confidence interval [CI; 0.053, 0.086], compared to the control trial, 0.047 °C/min 95% CI [0.038, 0.056]. Additionally, the time to decrease to less than 38.0 °C was significantly (P = .018) faster in the ISC trial (median = 9.3 minutes) compared to the control trial (median = 26.6 minutes). CONCLUSION ISC increases the cooling rate of those recovering from exertional hyperthermia. With the observed cooling rate, we can extrapolate that ISC would reduce core temperature by ∼2 °C within 30 minutes during a case of EHS. We conclude that ISC provides a safe and effective alternative for the field where cold water immersion resources may not be readily available.
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Affiliation(s)
- Aaron R Caldwell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA.,Oak Ridge Institute of Science and Education, Belcamp, MD 21017, USA
| | - Michelle M Saillant
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA.,Oak Ridge Institute of Science and Education, Belcamp, MD 21017, USA
| | - Dina Pitsas
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA.,Oak Ridge Institute of Science and Education, Belcamp, MD 21017, USA
| | - Audrey Johnson
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Karleigh E Bradbury
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, MA 01760, USA
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Bouchama A, Abuyassin B, Lehe C, Laitano O, Jay O, O'Connor FG, Leon LR. Classic and exertional heatstroke. Nat Rev Dis Primers 2022; 8:8. [PMID: 35115565 DOI: 10.1038/s41572-021-00334-6] [Citation(s) in RCA: 124] [Impact Index Per Article: 62.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/20/2021] [Indexed: 12/28/2022]
Abstract
In the past two decades, record-breaking heatwaves have caused an increasing number of heat-related deaths, including heatstroke, globally. Heatstroke is a heat illness characterized by the rapid rise of core body temperature above 40 °C and central nervous system dysfunction. It is categorized as classic when it results from passive exposure to extreme environmental heat and as exertional when it develops during strenuous exercise. Classic heatstroke occurs in epidemic form and contributes to 9-37% of heat-related fatalities during heatwaves. Exertional heatstroke sporadically affects predominantly young and healthy individuals. Under intensive care, mortality reaches 26.5% and 63.2% in exertional and classic heatstroke, respectively. Pathological studies disclose endothelial cell injury, inflammation, widespread thrombosis and bleeding in most organs. Survivors of heatstroke may experience long-term neurological and cardiovascular complications with a persistent risk of death. No specific therapy other than rapid cooling is available. Physiological and morphological factors contribute to the susceptibility to heatstroke. Future research should identify genetic factors that further describe individual heat illness risk and form the basis of precision-based public health response. Prioritizing research towards fundamental mechanism and diagnostic biomarker discovery is crucial for the design of specific management approaches.
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Affiliation(s)
- Abderrezak Bouchama
- King Abdullah International Medical Research Center, Experimental Medicine Department, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia.
| | - Bisher Abuyassin
- King Abdullah International Medical Research Center, Experimental Medicine Department, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia
| | - Cynthia Lehe
- King Abdullah International Medical Research Center, Experimental Medicine Department, King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard - Health Affairs, Riyadh, Saudi Arabia
| | - Orlando Laitano
- Department of Nutrition & Integrative Physiology, College of Health and Human Sciences, Florida State University, Tallahassee, FL, USA
| | - Ollie Jay
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Francis G O'Connor
- Military and Emergency Medicine, Uniformed Services University, Bethesda, MD, USA
| | - Lisa R Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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13
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Buller M, Fellin R, Bursey M, Galer M, Atkinson E, Beidleman BA, Marcello MJ, Driver K, Mesite T, Seay J, Weed L, Telfer B, King C, Frazee R, Moore C, Williamson JR. Gait instability and estimated core temperature predict exertional heat stroke. Br J Sports Med 2022; 56:446-451. [PMID: 35022161 DOI: 10.1136/bjsports-2021-104081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2021] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Exertional heat stroke (EHS), characterised by a high core body temperature (Tcr) and central nervous system (CNS) dysfunction, is a concern for athletes, workers and military personnel who must train and perform in hot environments. The objective of this study was to determine whether algorithms that estimate Tcr from heart rate and gait instability from a trunk-worn sensor system can forward predict EHS onset. METHODS Heart rate and three-axis accelerometry data were collected from chest-worn sensors from 1806 US military personnel participating in timed 4/5-mile runs, and loaded marches of 7 and 12 miles; in total, 3422 high EHS-risk training datasets were available for analysis. Six soldiers were diagnosed with heat stroke and all had rectal temperatures of >41°C when first measured and were exhibiting CNS dysfunction. Estimated core temperature (ECTemp) was computed from sequential measures of heart rate. Gait instability was computed from three-axis accelerometry using features of pattern dispersion and autocorrelation. RESULTS The six soldiers who experienced heat stroke were among the hottest compared with the other soldiers in the respective training events with ECTemps ranging from 39.2°C to 40.8°C. Combining ECTemp and gait instability measures successfully identified all six EHS casualties at least 3.5 min in advance of collapse while falsely identifying 6.1% (209 total false positives) examples where exertional heat illness symptoms were neither observed nor reported. No false-negative cases were noted. CONCLUSION The combination of two algorithms that estimate Tcr and ataxic gate appears promising for real-time alerting of impending EHS.
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Affiliation(s)
- Mark Buller
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Rebecca Fellin
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Max Bursey
- Augusta University, Augusta, Georgia, USA
| | - Meghan Galer
- Martin Army Community Hospital, Fort Benning, Georgia, USA
| | - Emma Atkinson
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Beth A Beidleman
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Michael J Marcello
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Kyla Driver
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Timothy Mesite
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Joseph Seay
- United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.,Natick Soldier Systems Center, Natick, Massachusetts, USA
| | - Lara Weed
- Massachusetts Institute of Technology Lincoln Laboratory, Lexington, Massachusetts, USA
| | - Brian Telfer
- Massachusetts Institute of Technology Lincoln Laboratory, Lexington, Massachusetts, USA
| | | | - Royce Frazee
- 75th Ranger Regiment, Fort Benning, Georgia, USA
| | | | - James R Williamson
- Massachusetts Institute of Technology Lincoln Laboratory, Lexington, Massachusetts, USA
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14
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Boden BP, Ahmed AE, Fine KM, Craven MJ, Deuster PA. Baseline Aerobic Fitness in High School and College Football Players: Critical for Prescribing Safe Exercise Regimens. Sports Health 2021; 14:490-499. [PMID: 34806472 DOI: 10.1177/19417381211058458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Nontraumatic fatalities occur on a regular basis in high school (HS) and college football athletes, primarily in obese linemen performing high-intensity exercise. One contributing factor to these deaths may be a mismatch between baseline aerobic (cardiorespiratory) fitness and exercise regimens. HYPOTHESIS There is a wide range of aerobic fitness in HS and college football players. Body mass index (BMI) is a safe and simple method for estimating baseline aerobic fitness. STUDY DESIGN Retrospective cohort study. LEVEL OF EVIDENCE Level 3. METHODS A retrospective review was performed on 79 HS football athletes who had VO2Peak (mL·kg-1·min-1) measured during the offseason. Multivariate regression analysis was used to determine if BMI (obese, overweight, and normal; kg/m2), position played (linemen vs other), year in school (freshmen vs other), and/or race (African American vs White) were risk factors for poor aerobic fitness. A separate cohort of 135 (48 HS; 87 college) football athletes performed a 6-minute run test to determine speed (miles/min), extrapolate VO2Max, and calculate reference values for suggested upper threshold safe starting speeds (85% of maximum) for aerobic training based on BMI. The relationship between BMI and VO2Peak was assessed. The exercise regimens (speeds) of 2 collegiate football fatalities from the public domain were used to predict their VO2Max values. RESULTS Mean VO2Peak (mL·kg-1·min-1) was 38.5 ± 8.6 (range 19.1-60.6); when grouped by BMI, low scores (<40) were found in 87.5% of obese (32.4 ± 7.7), 47.8% of overweight (40.8 ± 7.6), and 45.2% of normal (41.4 ± 7.8) athletes. VO2Peak was significantly lower in linemen (32.8 ± 6.4; P = 0.007) compared with nonlineman (41.8 ± 7.9), and in obese players (by BMI; 32.4; P = 0.019) compared with nonobese players (41.4 ± 7.6), but did not differ by age, year in school, or race. Means for speed (min/mile) and extrapolated VO2Max (mL·kg-1·min-1) for the 6-minute run test by BMI groups were both significantly different (P = 0.001) for normal (7.0 ± 0.6; 51.1 ± 2.6), overweight (7.6 ± 0.8; 46.5 ± 3.2), and obese (8.9 ± 1.5; 36.8 ± 5.9) athletes. There was a significant negative correlation (r = -0.551; P = 0.001; R2 = 0.304) between VO2Peak and BMI. Safe starting speed recommendations for running 1 mile range from 7.3 to 12.1 min/mile for BMIs 20 to 40 kg/m2 for HS and college athletes. For the 2 fatalities (mean, BMI of 36.5 kg/m2) repetitive sprint speeds were 49 and 89% higher than our safe starting speeds for their BMI. CONCLUSION A large spectrum of baseline aerobic fitness was noted in HS and college football players. Obese players and linemen had statistically lower baseline aerobic fitness, a major risk factor for possible heat illness. BMI is an acceptable surrogate for VO2Peak and can be employed to develop safe training regimens without the need for a maximum fitness test, which can place the athlete at risk for a medical event. CLINICAL RELEVANCE Knowledge of BMI provides an estimate of baseline aerobic fitness and a foundation for prescribing safe, individualized exercise regimens.
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Affiliation(s)
- Barry P Boden
- The Orthopaedic Center, a Division of CAO, Rockville, Maryland
| | - Anwar E Ahmed
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Kenneth M Fine
- The Orthopaedic Center, a Division of CAO, Rockville, Maryland
| | | | - Patricia A Deuster
- Consortium for Health and Military Performance, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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15
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Caldwell AR, Oki K, Ward SM, Ward JA, Mayer TA, Plamper ML, King MA, Leon LR. Impact of successive exertional heat injuries on thermoregulatory and systemic inflammatory responses in mice. J Appl Physiol (1985) 2021; 131:1469-1485. [PMID: 34528459 DOI: 10.1152/japplphysiol.00160.2021] [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] [Indexed: 12/29/2022] Open
Abstract
The purpose of the study was to determine if repeated exertional heat injuries (EHIs) worsen the inflammatory response. We assessed the impact of a single EHI bout (EHI0) or two separate EHI episodes separated by 1 (EHI1), 3 (EHI3), and 7 (EHI7) days in male C57BL/6J mice (n = 236). To induce EHI, mice underwent a forced running protocol until loss of consciousness or core temperature reached ≥ 42.7°C. Blood and tissue samples were obtained 30 min, 3 h, 1 day, or 7 days after the EHI. We observed that mice undergoing repeated EHI (EHI1, EHI3, and EHI7) had longer running distances before collapse (∼528 m), tolerated higher core temperatures (∼0.18°C higher) before collapse, and had higher minimum core temperature (indicative of injury severity) during recovery relative to EHI0 group (∼2.18°C higher; all P < 0.05). Heat resilience was most pronounced when latency was shortest between EHI episodes (i.e., thermal load and running duration highest in EHI1), suggesting the response diminishes with longer recoveries between EHI events. Furthermore, mice experiencing a second EHI exhibited increased serum and liver HSP70, and lower corticosterone, FABP2, MIP-1β, MIP-2, and IP-10 relative to mice experiencing a single EHI typically at 30 min to 3 h after EHI. Our findings indicate that an EHI event may initiate some adaptive processes that provide acute heat resilience to subsequent EHI conditions. NEW & NOTEWORTHY Mice undergoing repeated exertional heat injuries, within 1 wk of an initial heat injury, appear to have some protective adaptations. During the second exertional heat injury, mice were able to run longer and sustain higher body temperatures before collapse. Despite this, the mice undergoing a second exertional heat injury were more resilient to the heat as evidenced by attenuated minimum body temperature, higher HPS70 (serum and liver), lower corticosterone, and lower FABP2.
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Affiliation(s)
- Aaron R Caldwell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Kentaro Oki
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Shauna M Ward
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Jermaine A Ward
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Thomas A Mayer
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Mark L Plamper
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Michelle A King
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Lisa R Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
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16
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Scarneo-Miller SE, Lopez RM, Miller KC, Adams WM, Kerr ZY, Casa DJ. High Schools' Adoption of Evidence-Based Practices for the Management of Exertional Heat Stroke. J Athl Train 2021; 56:1142-1153. [PMID: 34662417 PMCID: PMC8530428 DOI: 10.4085/1062-6050-361-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Exertional heat stroke (EHS) deaths can be prevented by adhering to best practices. OBJECTIVE To investigate high schools' adoption of policies and procedures for recognizing and treating patients with EHS and the factors influencing the adoption of a comprehensive policy. DESIGN Cross-sectional study. SETTING Online questionnaire. PATIENTS OR OTHER PARTICIPANTS Athletic trainers (ATs) practicing in the high school (HS) setting. MAIN OUTCOME MEASURE(S) Using the National Athletic Trainers' Association position statement on exertional heat illness, we developed an online questionnaire and distributed it to ATs to ascertain their schools' current written policies for using rectal temperature and cold-water immersion. The precaution adoption process model allowed for responses to be presented across the various health behavior stages (unaware if have the policy, unaware of the need for the policy, unengaged, undecided, decided not to act, decided to act, acting, and maintaining). Additional questions addressed perceptions of facilitators and barriers. Data are presented as proportions. RESULTS A total of 531 ATs completed the questionnaire. Overall, 16.9% (n = 62) reported adoption of all components for the proper recognition and treatment of EHS. The component with the highest adoption level was "cool first, transport second"; 74.1% (n = 110) of ATs described acting on or maintaining the policy. The most variability in the precaution adoption process model responses was for a rectal temperature policy; 28.7% (n = 103) of ATs stated they decided not to act and 20.1% (n = 72) stated they maintained the policy. The most frequently cited facilitator of and barrier to obtaining rectal temperature were a mandate from the state HS athletics association (n = 274, 51.5%) and resistance to or apprehension of parents or legal guardians (n = 311, 58.5%), respectively. CONCLUSIONS Athletic trainers in the HS setting appeared to be struggling to adopt a comprehensive EHS strategy, with rectal temperature continuing as the biggest challenge. Tailored strategies based on health behavior, facilitators, and barriers may aid in changing this paradigm.
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Affiliation(s)
| | | | | | - William M. Adams
- Department of Kinesiology, University of North Carolina at Greensboro
| | | | - Douglas J. Casa
- Department of Kinesiology, University of Connecticut, Storrs
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17
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Weiner CM, Kazman JB, Abraham PA, Deuster PA. Perceptual strain in a compensable hot environment: Accuracy and clinical correlates. J Therm Biol 2021; 100:102863. [PMID: 34503767 DOI: 10.1016/j.jtherbio.2021.102863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 10/22/2022]
Abstract
Heat strain monitoring indexes are important to prevent exertional heat illness (EHI) and uncover risk factors. Two indexes are the Physiological Strain Index (PSI) and a subjective PSI analogue, the Perceptual Strain Index (PeSI). The PeSI is a feasible alternative to PSI in field conditions, although the validity has been variable in previous research. However, the PeSI has been rarely examined at a low heat strain with compensable heat stress, such as during a heat tolerance test (HTT). This study evaluated the discrepancy between the maximal PeSI and maximal PSI achieved during a HTT and determined their association with EHI risk factors, including history of EHI, percent body fat (%BF), relative VO2max, fatigue and sleep status (n = 121; 47 without prior EHI, 74 with prior EHI). The PSI was calculated using the change in rectal temperature (Tre) and heart rate (HR) and PeSI was calculated based on the formula containing thermal sensation (TS), a Tre analogue, and rate of perceived exertion (RPE), a HR analogue. Significant associations were identified between PSI and PeSI and between PSIHR and PeSIHR in the total sample and between PSI and PeSI in the EHI group. Bland-Altman analyses indicated PeSI underestimated PSI in the total sample, PSIHR was greater than PeSIHR, and that PSIcore and PeSIcore were not significantly different, but values varied widely at different heat strains. This indicates the use of RPE underestimates HR and that the accuracy of TS to predict Tre may be subpar. This study also demonstrated that participants with higher %BF have a decreased perception of heat strain and that post-fatigue, sleep status and a prior EHI may increase the perception of heat strain. Overall, these results suggest that PeSI is a poor surrogate for PSI in a compensable heat stress environment at low heat strain.
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Affiliation(s)
- Cynthia M Weiner
- Consortium for Health and Military Performance, Department of Military & Emergency Medicine, F. Edward Hébert School of Medicine, Uniformed Services University, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, USA
| | - Josh B Kazman
- Consortium for Health and Military Performance, Department of Military & Emergency Medicine, F. Edward Hébert School of Medicine, Uniformed Services University, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, USA.
| | - Preetha A Abraham
- Consortium for Health and Military Performance, Department of Military & Emergency Medicine, F. Edward Hébert School of Medicine, Uniformed Services University, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, USA
| | - Patricia A Deuster
- Consortium for Health and Military Performance, Department of Military & Emergency Medicine, F. Edward Hébert School of Medicine, Uniformed Services University, USA
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18
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Roberts WO, Armstrong LE, Sawka MN, Yeargin SW, Heled Y, O'Connor FG. ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity. Curr Sports Med Rep 2021; 20:470-484. [PMID: 34524191 DOI: 10.1249/jsr.0000000000000878] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
ABSTRACT Exertional heat stroke (EHS) is a true medical emergency with potential for organ injury and death. This consensus statement emphasizes that optimal exertional heat illness management is promoted by a synchronized chain of survival that promotes rapid recognition and management, as well as communication between care teams. Health care providers should be confident in the definitions, etiologies, and nuances of exertional heat exhaustion, exertional heat injury, and EHS. Identifying the athlete with suspected EHS early in the course, stopping activity (body heat generation), and providing rapid total body cooling are essential for survival, and like any critical life-threatening situation (cardiac arrest, brain stroke, sepsis), time is tissue. Recovery from EHS is variable, and outcomes are likely related to the duration of severe hyperthermia. Most exertional heat illnesses can be prevented with the recognition and modification of well-described risk factors ideally addressed through leadership, policy, and on-site health care.
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Affiliation(s)
- William O Roberts
- Department of Family Medicine and Community Health, University of Minnesota Medical School, Minneapolis, MN
| | | | - Michael N Sawka
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA
| | - Susan W Yeargin
- Department of Exercise Science, University of South Carolina, Columbia, SC
| | - Yuval Heled
- Clinical and Integrative Physiology Unit, Heller Institute of Medical Research, Sheba Medical Center, ISRAEL
| | - Francis G O'Connor
- Consortium for Health and Military Performance, Uniformed Services University of the Health Sciences, Bethesda, MD
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19
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Kruijt N, den Bersselaar LV, Snoeck M, Kramers K, Riazi S, Bongers C, Treves S, Jungbluth H, Voermans N. RYR1-related rhabdomyolysis: a spectrum of hypermetabolic states due to ryanodine receptor dysfunction. Curr Pharm Des 2021; 28:2-14. [PMID: 34348614 DOI: 10.2174/1381612827666210804095300] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/10/2021] [Indexed: 11/22/2022]
Abstract
Variants in the ryanodine receptor-1 gene (RYR1) have been associated with a wide range of neuromuscular conditions, including various congenital myopathies and malignant hyperthermia (MH). More recently, a number of RYR1 variants, mostly MH-associated, have been demonstrated to contribute to rhabdomyolysis events not directly related to anesthesia in otherwise healthy individuals. This review focuses on RYR1-related rhabdomyolysis, in the context of several clinical presentations (i.e., exertional rhabdomyolysis, exertional heat illnesses and MH), and conditions involving a similar hypermetabolic state, in which RYR1 variants may be present (i.e., neuroleptic malignant syndrome and serotonin syndrome). The variety of triggers that can evoke rhabdomyolysis, on their own or in combination, as well as the number of potentially associated complications, illustrates that this is a condition relevant to several medical disciplines. External triggers include but are not limited to strenuous physical exercise, especially if unaccustomed or performed under challenging environmental conditions (e.g., high ambient temperature or humidity), alcohol/illicit drugs, prescription medication (in particular statins, other anti-lipid agents, antipsychotics and antidepressants) infection, or heat. Amongst all patients presenting with rhabdomyolysis, a genetic susceptibility is present in a proportion, with RYR1 being one of the most common genetic causes. Clinical clues for a genetic susceptibility include recurrent rhabdomyolysis, creatine kinase (CK) levels above 50 times the upper limit of normal, hyperCKemia lasting for 8 weeks or longer, drug/medication doses insufficient to explain the rhabdomyolysis event, and a positive family history. For the treatment or prevention of RYR1-related rhabdomyolysis, the RYR1 antagonist dantrolene can be administered, both in the acute phase, or prophylactically in patients with a history of muscle cramps and/or recurrent rhabdomyolysis events. Aside from dantrolene, several other drugs are being investigated for their potential therapeutic use in RYR1-related disorders. These findings offer further therapeutic perspectives for humans, suggesting an important area for future research.
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Affiliation(s)
- Nick Kruijt
- Department of Neurology, Radboud University Medical Centre, Nijmegen. Netherlands
| | | | - Marc Snoeck
- Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital, Nijmegen. Netherlands
| | - Kees Kramers
- Department of Pharmacology and Toxicology, Radboud University Medical Centre, Nijmegen. Netherlands
| | - Sheila Riazi
- Department of Anesthesiology and Pain Medicine, University Health Network, University of Toronto, Toronto, ON. Canada
| | - Coen Bongers
- Department of Physiology, Radboudumc, Nijmegen. Netherlands
| | - Susan Treves
- Department of Biomedicine, University Hospital Basel. Switzerland
| | - Heinz Jungbluth
- Department of Paediatric Neurology - Neuromuscular Service, Evelina Children's Hospital, Guy's & St Thomas' NHS Foundation Trust, London. United Kingdom
| | - Nicol Voermans
- Department of Neurology, Radboud University Medical Centre, Nijmegen. Netherlands
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20
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Yeargin S, Torres-McGehee TM, Emerson D, Koller J, Dickinson J. Hydration, Eating Attitudes and Behaviors in Age and Weight-Restricted Youth American Football Players. Nutrients 2021; 13:nu13082565. [PMID: 34444723 PMCID: PMC8401195 DOI: 10.3390/nu13082565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/19/2021] [Accepted: 07/21/2021] [Indexed: 01/17/2023] Open
Abstract
There is a paucity of research examining hydration and nutrition behaviors in youth American football players. A potentially unique risk factor are league restrictions based on weight (WR) or age (AR). The purpose of this study was to examine hydration status between WR and AR leagues. The secondary purpose was to describe eating patterns in players. An observational cohort design with 63 youth football players (10 ± 1 yrs, 148.2 ± 9.4 cm, 44.9 ± 15.3 kg) was utilized. Independent variables were league (AR (n = 36); WR (n = 27)) and activity type (practice (PX = 8); game (GM = 3)). Dependent variables were hydration status (urine osmolality; percent change in body mass (%BM)), eating attitudes (Children’s Eating Attitude Test (ChEAT-26)) and self-reported frequency of meals. On average, players arrived activity mildly hypohydrated (830 ± 296 mOsm/kg) and %BM was minimal (−0.1 ± 0.7%) during events. Players consumed 2 ± 1 meals and 1 ± 1 snack before events. The ChEAT-26 survey reported 21.6% (n = 8) of players were at risk for abnormal eating attitudes. Among these players, eating binges, vomiting, excessive exercise and drastic weight loss were reported. Youth American football players arrived activity mildly hypohydrated and consumed enough fluid during activity to maintain euhydration. Abnormal eating attitudes and the use of unhealthy weight loss methods were reported by some youth American football players.
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Affiliation(s)
- Susan Yeargin
- Exercise Science Department, Arnold School of Public Health University of South Carolina, Columbia, SC 29208, USA;
- Correspondence:
| | - Toni M. Torres-McGehee
- Exercise Science Department, Arnold School of Public Health University of South Carolina, Columbia, SC 29208, USA;
| | - Dawn Emerson
- Department of Physical Therapy, Rehabilitation Sciences, and Athletic Training, School of Health Professions University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | | | - John Dickinson
- Palmetto Health/USC Orthopedic Center, Columbia, SC 29203, USA;
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21
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Adams WM, Hosokawa Y, Casa DJ, Périard JD, Racinais S, Wingo JE, Yeargin SW, Scarneo-Miller SE, Kerr ZY, Belval LN, Alosa D, Csillan D, LaBella C, Walker L. Roundtable on Preseason Heat Safety in Secondary School Athletics: Heat Acclimatization. J Athl Train 2021; 56:352-361. [PMID: 33878177 DOI: 10.4085/1062-6050-596-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To provide best-practice recommendations for developing and implementing heat-acclimatization strategies in secondary school athletics. DATA SOURCES An extensive literature review on topics related to heat acclimatization and heat acclimation was conducted by a group of content experts. Using the Delphi method, action-oriented recommendations were developed. CONCLUSIONS A period of heat acclimatization consisting of ≥14 consecutive days should be implemented at the start of fall preseason training or practices for all secondary school athletes to mitigate the risk of exertional heat illness. The heat-acclimatization guidelines should outline specific actions for secondary school athletics personnel to use, including the duration of training, the number of training sessions permitted per day, and adequate rest periods in a cool environment. Further, these guidelines should include sport-specific and athlete-specific recommendations, such as phasing in protective equipment and reintroducing heat acclimatization after periods of inactivity. Heat-acclimatization guidelines should be clearly detailed in the secondary school's policy and procedures manual and disseminated to all stakeholders. Heat-acclimatization guidelines, when used in conjunction with current best practices surrounding the prevention, management, and care of secondary school student-athletes with exertional heat stroke, will optimize their health and safety.
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Affiliation(s)
- William M Adams
- Hydration, Environment, and Thermal Stress Lab, Department of Kinesiology, University of North Carolina at Greensboro
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - Julien D Périard
- Research Institute for Sport and Exercise, University of Canberra, Bruce, Australia
| | - Sebastien Racinais
- Research and Scientific Support Department, ASPETAR Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | | | - Susan W Yeargin
- Department of Exercise Science, University of South Carolina, Columbia
| | | | - Zachary Y Kerr
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill
| | - Luke N Belval
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas
| | - Denise Alosa
- Athletic Medicine, South Burlington School District, Burlington, VT.,College of Nursing and Health Science, University of Vermont, Burlington
| | - David Csillan
- Department of Physical Therapy, Princeton Orthopedic Associates, NJ
| | - Cynthia LaBella
- Department of Pediatrics, Northwestern University Feinberg School of Medicine Institute for Sports Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, IL
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22
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Hosokawa Y, Racinais S, Akama T, Zideman D, Budgett R, Casa DJ, Bermon S, Grundstein AJ, Pitsiladis YP, Schobersberger W, Yamasawa F. Prehospital management of exertional heat stroke at sports competitions: International Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020. Br J Sports Med 2021; 55:1405-1410. [PMID: 33888465 PMCID: PMC8639927 DOI: 10.1136/bjsports-2020-103854] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2021] [Indexed: 12/22/2022]
Abstract
Objectives This document aimed to summarise the key components of exertional heat stroke (EHS) prehospital management. Methods Members of the International Olympic Committee Adverse Weather Impact Expert Working Group for the Olympic Games Tokyo 2020 summarised the current best practice regarding the EHS prehospital management. Results Sports competitions that are scheduled under high environmental heat stress or those that include events with high metabolic demands should implement and adopt policy and procedures for EHS prehospital management. The basic principles of EHS prehospital care are: early recognition, early diagnosis, rapid, on-site cooling and advanced clinical care. In order to achieve these principles, medical organisers must establish an area called the heat deck within or adjacent to the main medical tent that is optimised for EHS diagnosis, treatment and monitoring. Once admitted to the heat deck, the rectal temperature of the athlete with suspected EHS is assessed to confirm an elevated core body temperature. After EHS is diagnosed, the athlete must be cooled on-site until the rectal temperature is below 39°C. While cooling the athlete, medical providers are recommended to conduct a blood analysis to rule out exercise-associated hyponatraemia or hypoglycaemia, provided that this can be safely performed without interrupting cooling. The athlete is transported to advanced care for a full medical evaluation only after the treatment has been provided on-site. Conclusions A coordination of care among all medical stakeholders at the sports venue, during transport, and at the hospital is warranted to ensure effective management is provided to the EHS athlete.
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Affiliation(s)
- Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan
| | - Sebastien Racinais
- Research and Scientific Support Department, Aspetar Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Takao Akama
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan
| | - David Zideman
- Medical and Scientific Commission Games Group, International Olympic Committee, Lausanne, Switzerland
| | - Richard Budgett
- Medical and Scientific Department, International Olympic Committee, Lausanne, Switzerland
| | - Douglas J Casa
- Korey Stringer Institiute, Department of Kinesiology, University of Connecticut, Storrs, Connecticut, USA
| | - Stéphane Bermon
- Health and Science Department, World Athletics, Monaco.,LAMHESS, Université Côte d'Azur, Nice, France
| | | | - Yannis P Pitsiladis
- Collaborating Centre of Sports Medicine, University of Brighton, Eastbourne, UK
| | - Wolfgang Schobersberger
- Insitute for Sports Medicine, Alpine Medicine and Health Tourism, University for Health Sciences, Medical Informatics and Technology (UMIT), Hall, Austria
| | - Fumihiro Yamasawa
- Marubeni Health Promotion Center, Marubeni Corporation, Chuo-ku, Japan
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Miller KC, Casa DJ, Adams WM, Hosokawa Y, Cates J, Emrich C, Fitzpatrick T, Hopper M, Jardine JF, LaBotz M, Lopez RM, O'Connor F, Smith MS. Roundtable on Preseason Heat Safety in Secondary School Athletics: Prehospital Care of Patients With Exertional Heat Stroke. J Athl Train 2021; 56:372-382. [PMID: 33290540 PMCID: PMC8063668 DOI: 10.4085/1062-6050-0173.20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE First, we will update recommendations for the prehospital management and care of patients with exertional heat stroke (EHS) in the secondary school setting. Second, we provide action items to aid clinicians in developing best-practice documents and policies for EHS. Third, we supply practical strategies clinicians can use to implement best practice for EHS in the secondary school setting. DATA SOURCES An interdisciplinary working group of scientists, physicians, and athletic trainers evaluated the current literature regarding the prehospital care of EHS patients in secondary schools and developed this narrative review. When published research was nonexistent, expert opinion and experience guided the development of recommendations for implementing life-saving strategies. The group evaluated and further refined the action-oriented recommendations using the Delphi method. CONCLUSIONS Exertional heat stroke continues to be a leading cause of sudden death in young athletes and the physically active. This may be partly due to the numerous barriers and misconceptions about the best practice for diagnosing and treating patients with EHS. Exertional heat stroke is survivable if it is recognized early and appropriate measures are taken before patients are transported to hospitals for advanced medical care. Specifically, best practice for EHS evaluation and treatment includes early recognition of athletes with potential EHS, a rectal temperature measurement to confirm EHS, and cold-water immersion before transport to a hospital. With planning, communication, and persistence, clinicians can adopt these best-practice recommendations to aid in the recognition and treatment of patients with EHS in the secondary school setting.
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Affiliation(s)
- Kevin C. Miller
- School of Rehabilitation and Medical Sciences, Central Michigan University, Mount Pleasant
| | - Douglas J. Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - William M. Adams
- Department of Kinesiology, University of North Carolina at Greensboro
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
| | | | | | | | | | - John F. Jardine
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | | | - Rebecca M. Lopez
- Department of Orthopaedics and Sports Medicine, University of South Florida, Tampa
| | - Francis O'Connor
- Department of Military and Emergency Medicine, Uniformed Services University, Bethesda, MD
| | - M. Seth Smith
- Department of Orthopedics and Rehabilitation, University of Florida, Gainesville
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Keramidas ME, Botonis PG. Short-term sleep deprivation and human thermoregulatory function during thermal challenges. Exp Physiol 2021; 106:1139-1148. [PMID: 33745159 DOI: 10.1113/ep089467] [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: 02/08/2021] [Accepted: 03/16/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the topic of this review? It is generally accepted that sleep deprivation constitutes a predisposing factor to the development of thermal injury. This review summarizes the available human-based evidence on the impact of sleep loss on autonomic and behavioural thermoeffectors during acute exposure to low and high ambient temperatures. What advances does it highlight? Limited to moderate evidence suggests that sleep deprivation per se impairs thermoregulatory defence mechanisms during exposure to thermal extremes. Future research is required to establish whether inadequate sleep enhances the risk for cold- and heat-related illnesses. ABSTRACT Relatively short periods of inadequate sleep provoke physiological and psychological perturbations, typically leading to functional impairments and degradation in performance. It is commonly accepted that sleep deprivation also disturbs thermal homeostasis, plausibly enhancing susceptibility to cold- and heat-related illnesses. Herein, we summarize the current state of human-based evidence on the impact of short-term (i.e., ≤4 nights) sleep deprivation on autonomic and behavioural thermoeffectors during acute exposure to low and high ambient temperatures. The purpose of this brief narrative review is to highlight knowledge gaps in the area and stimulate future research to investigate whether sleep deprivation constitutes a predisposing factor for the development of thermal injuries.
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Affiliation(s)
- Michail E Keramidas
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Solna, Sweden
| | - Petros G Botonis
- School of Physical Education and Sports Science, National and Kapodistrian University of Athens, Athens, Greece
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Rublee C, Dresser C, Giudice C, Lemery J, Sorensen C. Evidence-Based Heatstroke Management in the Emergency Department. West J Emerg Med 2021; 22:186-195. [PMID: 33856299 PMCID: PMC7972371 DOI: 10.5811/westjem.2020.11.49007] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 11/25/2020] [Accepted: 11/20/2020] [Indexed: 11/14/2022] Open
Abstract
INTRODUCTION Climate change is causing an increase in the frequency and intensity of extreme heat events, which disproportionately impact the health of vulnerable populations. Heatstroke, the most serious heat-related illness, is a medical emergency that causes multiorgan failure and death without intervention. Rapid recognition and aggressive early treatment are essential to reduce morbidity and mortality. The objective of this study was to evaluate current standards of care for the emergent management of heatstroke and propose an evidence-based algorithm to expedite care. METHODS We systematically searched PubMed, Embase, and key journals, and reviewed bibliographies. Original research articles, including case studies, were selected if they specifically addressed the recognition and management of heatstroke in any prehospital, emergency department (ED), or intensive care unit population. Reviewers evaluated study quality and abstracted information regarding demographics, scenario, management, and outcome. RESULTS In total, 63 articles met full inclusion criteria after full-text review and were included for analysis. Three key themes identified during the qualitative review process included recognition, rapid cooling, and supportive care. Rapid recognition and expedited external or internal cooling methods coupled with multidisciplinary management were associated with improved outcomes. Delays in care are associated with adverse outcomes. We found no current scalable ED alert process to expedite early goal-directed therapies. CONCLUSION Given the increased risk of exposure to heat waves and the time-sensitivity of the condition, EDs and healthcare systems should adopt processes for rapid recognition and management of heatstroke. This study proposes an evidence-based prehospital and ED heat alert pathway to improve early diagnosis and resource mobilization. We also provide an evidence-based treatment pathway to facilitate efficient patient cooling. It is hoped that this protocol will improve care and help healthcare systems adapt to changing environmental conditions.
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Affiliation(s)
- Caitlin Rublee
- University of Colorado School of Medicine, Department of Emergency Medicine, Aurora, Colorado
| | - Caleb Dresser
- Harvard Medical School, Beth Israel Deaconess Medical Center, Department of Emergency Medicine, Boston, Massachusetts
| | - Catharina Giudice
- Los Angeles County and University of Southern California, Department of Emergency Medicine, Los Angeles, California
| | - Jay Lemery
- University of Colorado School of Medicine, Department of Emergency Medicine, Aurora, Colorado
| | - Cecilia Sorensen
- University of Colorado School of Medicine, Department of Emergency Medicine, Aurora, Colorado
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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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Yeargin SW, Dickinson JJ, Emerson DM, Koller J, Torres-McGehee TM, Kerr ZY. Exertional heat illness risk factors and physiological responses of youth football players. JOURNAL OF SPORT AND HEALTH SCIENCE 2021; 10:91-98. [PMID: 33518018 PMCID: PMC7856561 DOI: 10.1016/j.jshs.2019.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/07/2018] [Accepted: 10/09/2018] [Indexed: 06/12/2023]
Abstract
OBJECTIVE To determine which intrinsic and extrinsic exertional heat illness (EHI) risk factors exist in youth American football players and observe perceptual and physiological responses of players during events (games and practices). METHODS Cross-sectional cohort study observing 63 youth football players, varying in position. Independent variables were league (weight-restricted (WR, n = 27) and age-restricted (AR, n = 36)) and event type. Dependent variables were anthropometrics, work-to-rest ratio, and wet bulb globe temperature. Descriptive variables included preparticipation examination and uniform configuration. A subset of 16 players participated in physiological variables (heart rate and gastrointestinal temperature). Data collection occurred on 7 AR and 8 WR nonconsecutive practices and the first 3 games of the season. RESULTS Mean values for anthropometric variables were higher (p < 0.05) in the AR league than the WR league. Work time (χ2 (1,111) = 4.232; p = 0.039) and rest time (χ2 (1,111) = 43.41; p < 0.001) were significantly greater for games, but ratios were significantly higher for practices (χ2 (1,111) = 40.62; p < 0.001). The majority of events (77%) observed were in black and red flag wet bulb globe temperature risk categories. A total of 57% of the players had a preparticipation examination, and up to 82% of events observed were in full uniforms. Individual gastrointestinal temperature and heart rate responses ranged widely and no players reached critical thresholds. CONCLUSION Extrinsic (disproportionate work ratios, environmental conditions) and intrinsic (higher body mass index) EHI risk factors exist in youth football. Certain risk factors may be influenced by event and league type. National youth football organizations need to create thorough guidelines that address EHI risk factors for local leagues to adopt.
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Affiliation(s)
- Susan W Yeargin
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA.
| | - John J Dickinson
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; Palmetto Health/USC Orthopedic Center, Keenan High School, Columbia, SC 29203, USA
| | - Dawn M Emerson
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; Department of Health, Sport, and Exercise Sciences, University of Kansas, Lawrence, KS 66045, USA
| | - Jessica Koller
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA; Surgi-Care Inc., Boston, MA 02115, USA
| | - Toni M Torres-McGehee
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA
| | - Zachary Y Kerr
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC 27599-8700, USA
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28
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Turcano P, Chirila RM. 36-Year-Old Man With Respiratory Distress and Altered Mental Status. Mayo Clin Proc 2020; 95:e125-e130. [PMID: 33276851 DOI: 10.1016/j.mayocp.2020.04.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/22/2020] [Accepted: 04/03/2020] [Indexed: 10/22/2022]
Affiliation(s)
- Pierpaolo Turcano
- Resident in Neurology, Mayo Clinic School of Graduate Medical Education, Jacksonville, FL
| | - Razvan M Chirila
- Advisor to resident and Consultant in General Internal Medicine, Mayo Clinic, Jacksonville, FL.
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Ashworth ET, Cotter JD, Kilding AE. Methods for improving thermal tolerance in military personnel prior to deployment. Mil Med Res 2020; 7:58. [PMID: 33248459 PMCID: PMC7700709 DOI: 10.1186/s40779-020-00287-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/10/2020] [Indexed: 12/16/2022] Open
Abstract
Acute exposure to heat, such as that experienced by people arriving into a hotter or more humid environment, can compromise physical and cognitive performance as well as health. In military contexts heat stress is exacerbated by the combination of protective clothing, carried loads, and unique activity profiles, making them susceptible to heat illnesses. As the operational environment is dynamic and unpredictable, strategies to minimize the effects of heat should be planned and conducted prior to deployment. This review explores how heat acclimation (HA) prior to deployment may attenuate the effects of heat by initiating physiological and behavioural adaptations to more efficiently and effectively protect thermal homeostasis, thereby improving performance and reducing heat illness risk. HA usually requires access to heat chamber facilities and takes weeks to conduct, which can often make it impractical and infeasible, especially if there are other training requirements and expectations. Recent research in athletic populations has produced protocols that are more feasible and accessible by reducing the time taken to induce adaptations, as well as exploring new methods such as passive HA. These protocols use shorter HA periods or minimise additional training requirements respectively, while still invoking key physiological adaptations, such as lowered core temperature, reduced heart rate and increased sweat rate at a given intensity. For deployments of special units at short notice (< 1 day) it might be optimal to use heat re-acclimation to maintain an elevated baseline of heat tolerance for long periods in anticipation of such an event. Methods practical for military groups are yet to be fully understood, therefore further investigation into the effectiveness of HA methods is required to establish the most effective and feasible approach to implement them within military groups.
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Affiliation(s)
- Edward Tom Ashworth
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, 17 Antares Place, Rosedale, Auckland, 0632 New Zealand
| | - James David Cotter
- School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, Otago 9016 New Zealand
| | - Andrew Edward Kilding
- Sports Performance Research Institute New Zealand (SPRINZ), Auckland University of Technology, 17 Antares Place, Rosedale, Auckland, 0632 New Zealand
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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: 30] [Impact Index Per Article: 7.5] [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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Yeargin S, Hirschhorn R, Grundstein A. Heat-Related Illnesses Transported by United States Emergency Medical Services. MEDICINA (KAUNAS, LITHUANIA) 2020; 56:E543. [PMID: 33080867 PMCID: PMC7602997 DOI: 10.3390/medicina56100543] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 11/17/2022]
Abstract
Background and objectives: Heat-related illness (HRI) can have significant morbidity and mortality consequences. Research has predominately focused on HRI in the emergency department, yet health care leading up to hospital arrival can impact patient outcomes. Therefore, the purpose of this study was to describe HRI in the prehospital setting. Materials and Methods: A descriptive epidemiological design was utilized using data from the National Emergency Medical Services (EMS) Information System for the 2017-2018 calendar years. Variables of interest in this study were: patient demographics (age, gender, race), US census division, urbanicity, dispatch timestamp, incident disposition, primary provider impression, and regional temperatures. Results: There were 34,814 HRIs reported. The majority of patients were white (n = 10,878, 55.6%), males (n = 21,818, 62.7%), and in the 25 to 64 age group (n = 18,489, 53.1%). Most HRIs occurred in the South Atlantic US census division (n = 11,732, 33.7%), during the summer (n = 23,873, 68.6%), and in urban areas (n = 27,541, 83.5%). The hottest regions were East South Central, West South Central, and South Atlantic, with peak summer temperatures in excess of 30.0 °C. In the spring and summer, most regions had near normal temperatures within 0.5 °C of the long-term mean. EMS dispatch was called for an HRI predominately between the hours of 11:00 a.m.-6:59 p.m. (n = 26,344, 75.7%), with the majority (27,601, 79.3%) of HRIs considered heat exhaustion and requiring the patient to be treated and transported (n = 24,531, 70.5%). Conclusions: All age groups experienced HRI but particularly those 25 to 64 years old. Targeted education to increase public awareness of HRI in this age group may be needed. Region temperature most likely explains why certain divisions of the US have higher HRI frequency. Afternoons in the summer are when EMS agencies should be prepared for HRI activations. EMS units in high HRI frequency US divisions may need to carry additional treatment interventions for all HRI types.
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Affiliation(s)
- Susan Yeargin
- Department of Exercise Science, University of South Carolina, Columbia, SC 29208, USA
| | | | - Andrew Grundstein
- Department of Geography, University of Georgia, Athens, GA 30602, USA;
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Alele FO, Malau-Aduli BS, Malau-Aduli AEO, J. Crowe M. Epidemiology of Exertional Heat Illness in the Military: A Systematic Review of Observational Studies. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:E7037. [PMID: 32993024 PMCID: PMC7579124 DOI: 10.3390/ijerph17197037] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022]
Abstract
Exertional heat illness (EHI) is an occupational hazard among military personnel. This systematic review describes the incidence, risk factors, clinical manifestations, and biomarkers of EHI in the military. Six databases from inception to 28 May 2020 were systematically reviewed using the PRISMA guidelines. Forty-one articles met the inclusion criteria and the incidence of EHI ranged from 0.2 to 10.5 per 1000 person years, while the prevalence rates ranged from 0.3% to 9.3%. Intrinsic risk factors influencing EHI were gender, physical fitness, obesity, previous history of heat illness, and motivation, while the extrinsic factors included hot environmental conditions and service unit. Evidence suggests that loss of consciousness, absence of sweating and confusion were the common clinical features of exertional heat stroke (EHS). The mean core temperature ranged from 40 to 41.6 °C, while elevated levels of creatine phosphokinase, liver enzymes, and creatinine were common biochemical markers of EHS. The findings of the review suggest a variation in the incidence of EHI among military populations possibly due to the varying definitions used. Although some risk factors of EHI were identified, more analytical studies are needed to investigate the association between EHI and other important factors such as acclimatisation and occlusive clothing.
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Affiliation(s)
- Faith O. Alele
- College of Healthcare Sciences, James Cook University, Townsville QLD 4811, Australia
| | - Bunmi S. Malau-Aduli
- College of Medicine and Dentistry, James Cook University, Townsville QLD 4811, Australia;
| | - Aduli E. O. Malau-Aduli
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville QLD 4811, Australia;
| | - Melissa J. Crowe
- Division of Tropical Health and Medicine, James Cook University, Townsville QLD 4811, Australia;
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Returning to Sport Following COVID-19: Considerations for Heat Acclimatization in Secondary School Athletics. Sports Med 2020; 50:1555-1557. [PMID: 32535850 PMCID: PMC7293168 DOI: 10.1007/s40279-020-01301-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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34
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Epidemiology of exertional heat illnesses in organised sports: A systematic review. J Sci Med Sport 2020; 23:701-709. [DOI: 10.1016/j.jsams.2020.02.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/13/2020] [Accepted: 02/07/2020] [Indexed: 11/21/2022]
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Boden BP, Fine KM, Spencer TA, Breit I, Anderson SA. Nontraumatic Exertional Fatalities in Football Players, Part 2: Excess in Conditioning Kills. Orthop J Sports Med 2020; 8:2325967120943491. [PMID: 32913873 PMCID: PMC7444123 DOI: 10.1177/2325967120943491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 04/23/2020] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND The incidence of nontraumatic fatalities in high school (HS) and National Collegiate Athletic Association (NCAA) football players has continued at a constant rate since the 1960s. PURPOSE To describe the causes of nontraumatic fatalities in HS and NCAA football players and provide prevention strategies. STUDY DESIGN Descriptive epidemiology study. METHODS We reviewed 187 fatalities in HS and NCAA nontraumatic football players catalogued by the National Registry of Catastrophic Sports Injuries during a 20-year period between July 1998 and June 2018. RESULTS The majority (n = 162; 86.6%) of fatalities occurred during a practice or conditioning session. Most fatalities, when timing was known, (n = 126; 70.6%) occurred outside of the regular playing season, with the highest incidence in the August preseason (n = 64; 34.2%). All documented conditioning sessions were supervised by a coach (n = 92) or strength and conditioning coach (n = 40). The exercise regimen at the time of the fatality involved high-intensity aerobic training in 94.7%. Punishment was identified as the intent in 36 fatalities. The average body mass index of the athletes was 32.6 kg/m2. For athletes who died due to exertional heat stroke, the average body mass index was 36.4 kg/m2, and 97.1% were linemen. CONCLUSION Most nontraumatic fatalities in HS and NCAA football players occurred during coach-supervised conditioning sessions. The primary cause of exertion-related fatalities was high-intensity aerobic workouts that might have been intended as punishment and/or excess repetitions. Exertion-related fatalities are potentially preventable by applying standards in workout design, holding coaches accountable, and ensuring compliance with the athlete's health and current welfare policies.
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Affiliation(s)
- Barry P. Boden
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Ken M. Fine
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Tiahna A. Spencer
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Ilan Breit
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Scott A. Anderson
- Department of Athletics, University of Oklahoma, Norman, Oklahoma, USA
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Boden BP, Fine KM, Breit I, Lentz W, Anderson SA. Nontraumatic Exertional Fatalities in Football Players, Part 1: Epidemiology and Effectiveness of National Collegiate Athletic Association Bylaws. Orthop J Sports Med 2020; 8:2325967120942490. [PMID: 32884961 PMCID: PMC7440734 DOI: 10.1177/2325967120942490] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 04/23/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Football has the highest number of nontraumatic fatalities of any sport in the United States. PURPOSE To compare the incidence of nontraumatic fatalities with that of traumatic fatalities, describe the epidemiology of nontraumatic fatalities in high school (HS) and college football players, and determine the effectiveness of National Collegiate Athletic Association (NCAA) policies to reduce exertional heat stroke (EHS) and exertional sickling (ES) with sickle cell trait (SCT) fatalities in athletes. STUDY DESIGN Descriptive epidemiology study. METHODS We retrospectively reviewed 20 academic years (1998-2018) of HS and college nontraumatic fatalities in football players using the National Registry of Catastrophic Sports Injuries (NRCSI). EHS and ES with SCT fatality rates were compared before and after the implementation of the NCAA football out-of-season model (bylaw 17.10.2.4 [2003]) and NCAA Division I SCT screening (bylaw 17.1.5.1 [2010]), respectively. Additionally, we compiled incidence trends for HS and college traumatic and nontraumatic fatalities in football players for the years 1960 through 2018 based on NRCSI data and previously published reports. RESULTS The risk (odds ratio) of traumatic fatalities in football players in the 2010s was 0.19 (95% CI, 0.13-0.26; P < .0001) lower in HS and 0.29 (95% CI, 0.29-0.72; P = .0078) lower in college compared with that in the 1960s. In contrast, the risk of nontraumatic fatalities in football players in the 2010s was 0.7 (95% CI, 0.50-0.98; P = .0353) in HS and 0.9 (95% CI, 0.46-1.72; P = .7413) in college compared with that in the 1960s. Since 2000, the risk of nontraumatic fatalities has been 1.89 (95% CI, 1.42-2.51; P < .001) and 4.22 (95% CI, 2.04-8.73; P < .001) higher than the risk of traumatic fatalities at the HS and college levels, respectively. During the 20 years studied, there were 187 nontraumatic fatalities (average, 9.4 per year). The causes of death were sudden cardiac arrest (57.7%), EHS (23.6%), ES with SCT (12.1%), asthma (4.9%), and hyponatremia (1.6%). The risk of a nontraumatic fatality was 4.1 (95% CI, 2.8-5.9; P < .0001) higher in NCAA compared with HS athletes. There was no difference in the risk of an EHS fatality in NCAA athletes (0.86 [95% CI, 0.17-4.25]; P = .85) after implementation in 2003 of the NCAA football out-of-season model. The risk of an ES with SCT fatality in Division I athletes was significantly lower after the 2010 NCAA SCT screening bylaw was implemented (0.12 [95% CI, 0.02-0.95]; P = .04). CONCLUSION Since the 1960s, the risk of nontraumatic fatalities has declined minimally compared with the reduction in the risk of traumatic fatalities. Current HS and college nontraumatic fatality rates are significantly higher than rates of traumatic fatalities. The 2003 NCAA out-of-season model has failed to significantly reduce EHS fatalities. The 2010 NCAA SCT screening bylaw has effectively prevented ES with SCT fatalities in NCAA Division I football.
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Affiliation(s)
- Barry P. Boden
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Ken M. Fine
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Ilan Breit
- The Orthopaedic Center, Centers for Advanced Orthopaedics, Rockville, Maryland, USA
| | - Wendee Lentz
- College of Professional and Continuing Studies, University of Oklahoma, Norman, Oklahoma, USA
| | - Scott A. Anderson
- Department of Athletics, University of Oklahoma, Norman, Oklahoma, USA
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Hagen J, Himmler A, Clark J, Ramadan J, Stone J, Divine J, Mangine R. Test and Evaluation of Heart Rate Derived Core Temperature Algorithms for Use in NCAA Division I Football Athletes. J Funct Morphol Kinesiol 2020; 5:E46. [PMID: 33467262 PMCID: PMC7739355 DOI: 10.3390/jfmk5030046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/26/2020] [Accepted: 07/01/2020] [Indexed: 12/02/2022] Open
Abstract
The purpose of this study was to assess the validity of utilizing heart rate to derive an estimate of core body temperature in American Football athletes. This was evaluated by combining commercially available Zephyr Bioharness devices, which includes an embedded estimated core temperature (ECT) algorithm, and an ingestible radio frequency core temperature pill during the highest heat injury risk timepoint of the season, summer training camp. Results showed a concordance of 0.643 and 78% of all data points fell within +/-1.0 °F. When the athletes were split into Upper (>/=6.0%) and Lower (<6.0%) body composition groups, there was a statistical improvement in accuracy with the Upper Body Fat% reaching 0.834 concordance and 93% of all values falling within +/-1.0 °F of the Gold Standard. Results suggest that heart rate derived core temperature assessments are a viable tool for heat stress monitoring in American football, but more work is required to improve on accuracy based on body composition.
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Affiliation(s)
- Joshua Hagen
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26505, USA; (J.H.); (J.R.); (J.S.)
| | - Aaron Himmler
- Department of Athletics, University of Cincinnati, Cincinnati, OH 45221, USA; (A.H.); (J.C.); (J.D.)
| | - Joseph Clark
- Department of Athletics, University of Cincinnati, Cincinnati, OH 45221, USA; (A.H.); (J.C.); (J.D.)
| | - Jad Ramadan
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26505, USA; (J.H.); (J.R.); (J.S.)
| | - Jason Stone
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26505, USA; (J.H.); (J.R.); (J.S.)
| | - Jon Divine
- Department of Athletics, University of Cincinnati, Cincinnati, OH 45221, USA; (A.H.); (J.C.); (J.D.)
| | - Robert Mangine
- Department of Athletics, University of Cincinnati, Cincinnati, OH 45221, USA; (A.H.); (J.C.); (J.D.)
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Maung Z, Tustin AW. The Heat Death Line: Proposed Heat Index Alert Threshold for Preventing Heat-Related Fatalities in the Civilian Workforce. New Solut 2020; 30:138-145. [PMID: 32552315 DOI: 10.1177/1048291120933819] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A threshold Heat Index (HI) can serve as the basis for advising the civilian workforce about the risk of heat-related illnesses. We conducted a systematic review and compiled reports of work-related fatalities from heat-related illnesses. We calculated the HI for each fatality. Our objective was to expand upon the military's concept of a "heat death line" and identify an HI alert threshold for the civilian workforce. We identified 14 publications totaling 570 heat-related deaths. In the meta-analysis, the median HI was 101 with a range of 62 to 137. Almost all deaths (96 percent and 99 percent of civilian and military fatalities, respectively) occurred when HI ≥80, which is our proposed heat death line. Some existing HI-based heat advisories are set at a higher temperature value. However, many occupational heat-related illnesses occur below these thresholds, resulting in low sensitivity and a false sense of security. In at-risk outdoor industries, HI ≥80 should trigger hazard awareness and protective actions.
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Affiliation(s)
- Zaw Maung
- Occupational Safety and Health Administration, Washington, DC, USA
| | - Aaron W Tustin
- Occupational Safety and Health Administration, Washington, DC, USA
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Abstract
Respiratory and gastrointestinal infections limit an athlete's availability to train and compete. To better understand how sick an athlete will become when they have an infection, a paradigm recently adopted from ecological immunology is presented that includes the concepts of immune resistance (the ability to destroy microbes) and immune tolerance (the ability to dampen defence yet control infection at a non-damaging level). This affords a new theoretical perspective on how nutrition may influence athlete immune health; paving the way for focused research efforts on tolerogenic nutritional supplements to reduce the infection burden in athletes. Looking through this new lens clarifies why nutritional supplements targeted at improving immune resistance in athletes show limited benefits: evidence supporting the old paradigm of immune suppression in athletes is lacking. Indeed, there is limited evidence that the dietary practices of athletes suppress immunity, e.g. low-energy availability and train- or sleep-low carbohydrate. It goes without saying, irrespective of the dietary preference (omnivorous, vegetarian), that athletes are recommended to follow a balanced diet to avoid a frank deficiency of a nutrient required for proper immune function. The new theoretical perspective provided sharpens the focus on tolerogenic nutritional supplements shown to reduce the infection burden in athletes, e.g. probiotics, vitamin C and vitamin D. Further research should demonstrate the benefits of candidate tolerogenic supplements to reduce infection in athletes; without blunting training adaptations and without side effects.
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Westwood CS, Fallowfield JL, Delves SK, Nunns M, Ogden HB, Layden JD. Individual risk factors associated with exertional heat illness: A systematic review. Exp Physiol 2020; 106:191-199. [PMID: 32249985 DOI: 10.1113/ep088458] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/30/2020] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the topic of this review? Exertional heat illness (EHI) remains a persistent problem for athletes and individuals. This threat remains despite numerous athletic position statements and occupational guidance policies. This review explores primary evidence that demonstrates a direct association between 'known' risk factors and EHI. What advances does it highlight? Primary evidence to support 'known' risk factors associated with EHI is not comprehensive. Furthermore, it is not evident that single individual factors predispose individuals to greater risk. In fact, the evidence indicates that EHI can manifest in non-hostile compensable environments when a combination of risk factors is prevalent. ABSTRACT Despite the widespread knowledge of exertional heat illness (EHI) and clear guidance for its prevention, the incidence of EHI remains high. We carried out a systematic review of available literature evaluating the scientific evidence underpinning the risk factors associated with EHI. Medline, PsycINFO, SportDiscus and Embase were searched from inception to January 2019 with no date limitation, with supplementary searches also being performed. Search terms included permutations of risk and heat illness, with only studies in English included. Study selection, data extraction and quality assessment, using the QUALSYST tool, were performed by two independent reviewers. Of 8898 articles identified by the searches, 42 were included in the systematic review as primary evidence demonstrating a link between a risk factor and EHI. The quality scores ranged from 57.50 to 100%, and studies were generally considered to be of strong quality. The majority of risks attributable to EHI were categorized as those associated with lifestyle factors. The findings from the systematic review suggest complex manifestation of EHI through multiple risk factors rather than any one factor in isolation. Further research is needed to explore the accumulation of risk factors to help in development of effective preventative measures.
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Affiliation(s)
- Caroline S Westwood
- School of Sport, Health and Wellbeing, Plymouth Marjon University, Plymouth, UK
| | | | | | - Michael Nunns
- Exeter Health Services and Delivery Research Evidence Synthesis Centre, Institute of Health Research, University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Henry B Ogden
- School of Sport, Health and Wellbeing, Plymouth Marjon University, Plymouth, UK
| | - Joseph D Layden
- School of Sport, Health and Wellbeing, Plymouth Marjon University, Plymouth, UK
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Do Alternative Cooling Methods Have Effective Cooling Rates for Hyperthermia Compared With Previously Established CWI Cooling Rates? J Sport Rehabil 2020; 29:367-372. [PMID: 31628268 DOI: 10.1123/jsr.2019-0098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 06/04/2019] [Accepted: 06/19/2019] [Indexed: 11/18/2022]
Abstract
Clinical Scenario: In the last few years, there have been several studies examining alternative cooling strategies in the treatment of exertional heat stroke (EHS). Morbidity and mortality with EHS are associated with how long the patient's core body temperature remains above the critical threshold of 40.5°C. Although cold-water immersion (CWI) is the gold standard of treatment when cooling a patient with EHS, more recent alternative cooling techniques have been examined for use in settings where CWI may not be feasible (ie, remote locations). Clinical Question: Do alternative cooling methods have effective core body temperature cooling rates for hyperthermia compared with previously established CWI cooling rates? Summary of Key Findings: The authors searched for studies using alternative cooling methods to cool hyperthermic individuals. To be included, the studies needed a PEDro score ≥6 and a level of evidence ≥2. They found 9 studies related to our focused clinical question; of these, 5 studies met the inclusion criteria. The cooling rates for hand cooling, cold-water shower, and ice-sheet cooling were 0.03°C/min, 0.08°C/min, and 0.06°C/min, respectively, whereas the tarp-assisted cooling with oscillation (TACO) method was the only method that had an acceptable cooling rate (range 0.14-0.17°C/min). Clinical Bottom Line: When treating EHS, if CWI is not available, the tarp-assisted cooling method may be a reasonable alternative. Clinicians should not use cold shower, hand cooling, or ice-sheet cooling if better cooling methods are available. Clinicians should always use CWI when available. Strength of Recommendation: Five level 2 studies with PEDro scores ≥6 suggest the TACO method is the only alternative cooling method that decreases core body temperature at a similar, though slower, rate of CWI. Hand cooling, cold showering, and ice-sheet cooling do not decrease core body temperature at an appropriate rate and should not be used in EHS situations if a modality with a better cooling rate is available.
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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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Current paradigms in the prehospital care of exertional heat illness: A review. CURRENT ORTHOPAEDIC PRACTICE 2019. [DOI: 10.1097/bco.0000000000000824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Grundstein AJ, Hosokawa Y, Casa DJ, Stearns RL, Jardine JF. Influence of Race Performance and Environmental Conditions on Exertional Heat Stroke Prevalence Among Runners Participating in a Warm Weather Road Race. Front Sports Act Living 2019; 1:42. [PMID: 33344965 PMCID: PMC7739836 DOI: 10.3389/fspor.2019.00042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 09/19/2019] [Indexed: 01/19/2023] Open
Abstract
The New Balance Falmouth Road Race held in Falmouth, Massachusetts, U.S. is a short distance race (11.26 km) that is well-known for high rates of exertional heat stroke (EHS). Previous research has documented the increased EHS rates with hotter and more humid weather conditions, yet did not explore the influence of race pacing on EHS risk. In this study, we leverage 15 years of data to investigate if runners who experienced an EHS moderate their average paces based on weather conditions and if there is a difference in average race pace between participants who experienced an EHS and other runners. Results indicate that runners who experience an EHS do not appear to reduce their average pace with increasing WBGT warning flag categories. In addition, runners who suffer an EHS run at a faster average pace than others, even when controlling for age, gender, race performance, and starting time WBGT. This suggests the important role of metabolic heat production as a risk factor of EHS. Since race pacing is a modifiable risk factor, our findings support the need for race organizers to actively encourage runners to adjust race pacing based on weather conditions.
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Affiliation(s)
| | - Yuri Hosokawa
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, United States
| | - Rebecca L Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, United States
| | - John F Jardine
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs, CT, United States.,Falmouth Hospital, Falmouth, MA, United States
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Affiliation(s)
- Yoram Epstein
- From the Heller Institute of Medical Research, Sheba Medical Center (Y.E., R.Y.), and Sackler Faculty of Medicine, Tel Aviv University (Y.E.) - both in Tel Aviv, Israel; and Wingate College for Physical Education and Sport Sciences, Wingate Institute, Netanya, Israel (R.Y.)
| | - Ran Yanovich
- From the Heller Institute of Medical Research, Sheba Medical Center (Y.E., R.Y.), and Sackler Faculty of Medicine, Tel Aviv University (Y.E.) - both in Tel Aviv, Israel; and Wingate College for Physical Education and Sport Sciences, Wingate Institute, Netanya, Israel (R.Y.)
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Hosokawa Y, Johnson EN, Jardine JF, Stearns RL, Casa DJ. Knowledge and Belief Toward Heat Safety and Hydration Strategies Among Runners: A Preliminary Evaluation. J Athl Train 2019; 54:541-549. [PMID: 31058540 DOI: 10.4085/1062-6050-520-17] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT Little is known about how educating runners may correct common misconceptions surrounding heat safety and hydration strategies. OBJECTIVE To investigate (1) beliefs and knowledge about heat safety and hydration strategies among recreational runners and (2) the effectiveness of an educational video in optimizing performance in the heat. DESIGN Cross-sectional study. SETTING Survey. PATIENTS OR OTHER PARTICIPANTS A total of 2091 (25.1%) of 8319 runners registered for the 2017 Falmouth Road Race completed at least 1 of the 3 administered surveys. INTERVENTION(S) A 5.3-minute video and an 11-question survey regarding heat safety and hydration strategies were developed, validated, and implemented. The survey was e-mailed to registrants 9 weeks before the race (PRERACE), after they viewed the video (POSTEDU), and the afternoon of the race (POSTRACE). MAIN OUTCOME MEASURE(S) The total score for responses to 2 multiple choice questions and nine 5-point (response range = strongly agree to strongly disagree) Likert-scale questions. RESULTS The PRERACE results showed that more than 90% of respondents recognized the importance of staying hydrated beginning the day before the planned activity, correctly identified that dark color urine is not a sign of euhydration, and believed that dehydration may increase the risk for heat syncope. Conversely, fewer than 50% of respondents knew the number of days required to achieve heat acclimatization, the role of sweat-rate calculation in optimizing one's hydration strategy, or the risk of water intoxication from drinking too much water. An improvement in survey score from PRERACE to POSTEDU was observed (mean difference = 2.00; 95% confidence interval = 1.68, 2.33; P < .001) among runners who watched the video, and 73% of the improvement in their scores was retained from POSTEDU to POSTRACE (mean difference = -0.54; 95% confidence interval = -0.86, -0.21; P < .001). CONCLUSIONS The video successfully shifted runners' beliefs and knowledge to enable them to better optimize their performance in the heat.
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Affiliation(s)
- Yuri Hosokawa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs.,Faculty of Sport Sciences, Waseda University, Saitama, Japan
| | - Elizabeth N Johnson
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - John F Jardine
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - Rebecca L Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
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Costa RJS, Gaskell SK, McCubbin AJ, Snipe RMJ. Exertional-heat stress-associated gastrointestinal perturbations during Olympic sports: Management strategies for athletes preparing and competing in the 2020 Tokyo Olympic Games. Temperature (Austin) 2019; 7:58-88. [PMID: 32166105 PMCID: PMC7053925 DOI: 10.1080/23328940.2019.1597676] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/05/2019] [Accepted: 03/14/2019] [Indexed: 12/15/2022] Open
Abstract
Exercise-induced gastrointestinal syndrome (EIGS) is a common characteristic of exercise. The causes appear to be multifactorial in origin, but stem primarily from splanchnic hypoperfusion and increased sympathetic drive. These primary causes can lead to secondary outcomes that include increased intestinal epithelial injury and gastrointestinal hyperpermeability, systemic endotoxemia, and responsive cytokinemia, and impaired gastrointestinal function (i.e. transit, digestion, and absorption). Impaired gastrointestinal integrity and functional responses may predispose individuals, engaged in strenuous exercise, to gastrointestinal symptoms (GIS), and health complications of clinical significance, both of which may have exercise performance implications. There is a growing body of evidence indicating heat exposure during exercise (i.e. exertional-heat stress) can substantially exacerbate these gastrointestinal perturbations, proportionally to the magnitude of exertional-heat stress, which is of major concern for athletes preparing for and competing in the upcoming 2020 Tokyo Olympic Games. To date, various hydration and nutritional strategies have been explored to prevent or ameliorate exertional-heat stress associated gastrointestinal perturbations. The aims of the current review are to comprehensively explore the impact of exertional-heat stress on markers of EIGS, examine the evidence for the prevention and (or) management of EIGS in relation to exertional-heat stress, and establish best-practice nutritional recommendations for counteracting EIGS and associated GIS in athletes preparing for and competing in Tokyo 2020.
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Affiliation(s)
- Ricardo J S Costa
- Monash University, Department of Nutrition Dietetics and Food, Notting Hill, Victoria, Australia
| | - Stephanie K Gaskell
- Monash University, Department of Nutrition Dietetics and Food, Notting Hill, Victoria, Australia
| | - Alan J McCubbin
- Monash University, Department of Nutrition Dietetics and Food, Notting Hill, Victoria, Australia
| | - Rhiannon M J Snipe
- Deakin University, Centre for Sport Research, School of Exercise and Nutrition Science, Burwood, Victoria, Australia
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Chan AP, Yang Y, Wong FK, Yam MC, Wong DP, Song WF. Reduction of Physiological Strain Under a Hot and Humid Environment by a Hybrid Cooling Vest. J Strength Cond Res 2019; 33:1429-1436. [DOI: 10.1519/jsc.0000000000001837] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Exertional heat stroke (EHS) remains one of the leading causes of sudden death in sport despite clear evidence showing 100% survivability with the proper standards of care in place and utilized. Of particular concern are student athletes competing at the secondary school level, where the extent of appropriate health care services remains suboptimal compared with organized athletics at the collegiate level and higher. While rapid recognition and rapid treatment of EHS ensures survival, the adoption and implementation of these lifesaving steps within secondary school athletics warrant further discussion within the sports medicine community. Establishing proper policies regarding the prevention and care of EHS coupled with utilizing an interdisciplinary care approach is essential for 1) minimizing risk and 2) guaranteeing optimal outcomes for the patient.
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Affiliation(s)
- William M Adams
- Department of Kinesiology, University of North Carolina at Greensboro, Greensboro, NC
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Scarneo SE, Kerr ZY, Kroshus E, Register-Mihalik JK, Hosokawa Y, Stearns RL, DiStefano LJ, Casa DJ. The Socioecological Framework: A Multifaceted Approach to Preventing Sport-Related Deaths in High School Sports. J Athl Train 2019; 54:356-360. [PMID: 30870600 DOI: 10.4085/1062-6050-173-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The socioecological framework is a multilevel conceptualization of health that includes intrapersonal, interpersonal, organizational, environmental, and public policy factors. The socioecological framework emphasizes multiple levels of influence and supports the idea that behaviors both affect and are affected by various contexts. At present, the sports medicine community's understanding and application of the socioecological framework are limited. In this article, we use the socioecological framework to describe potential avenues for interventions to reduce sport-related deaths among adolescent participants.
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Affiliation(s)
- Samantha E Scarneo
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | - Zachary Y Kerr
- Department of Exercise and Sport Science, University of North Carolina at Chapel Hill
| | - Emily Kroshus
- University of Washington, Department of Pediatrics, Seattle.,Seattle Children's Research Institute, Center for Child Health, Behavior and Development, WA
| | | | - Yuri Hosokawa
- College of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Rebecca L Stearns
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
| | | | - Douglas J Casa
- Korey Stringer Institute, Department of Kinesiology, University of Connecticut, Storrs
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