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Yamashita N, Kume M, Satake T, Inoue K, Yoshida T. Subjective perceived risk factors of exertional heat exhaustion-related symptoms in female collegiate athletes in Japan. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2024; 68:1303-1314. [PMID: 38598168 DOI: 10.1007/s00484-024-02667-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 03/19/2024] [Accepted: 04/01/2024] [Indexed: 04/11/2024]
Abstract
Associations of exertional heat exhaustion (EHE)-related symptoms with lifestyle habits and health factors specific to female athletes, ranked by relative risks from high to low, remain elusive. Addressing this issue would benefit athletes and coaches, ensuring safer practices during summer sports activities. To address this issue, we distributed paper-based questionnaires to seven universities in Japan, and 983 respondents completed our survey. The questionnaires covered various personal characteristics, lifestyle habits, perceived health factors, perceived athletic activity, and EHE-related symptoms. In this retrospective case-control study, we analyzed the relationships of EHE-related symptoms (objective variables) with lifestyle habits, health factors, and athletic activity conditions (explanatory variables) using the partial proportional odds model. The questionnaire responses revealed that perceived dehydration, sickness, loss of appetite, perceived accumulated fatigue, perceived mental stress, lack of ambient wind, and insufficient rest breaks were positively associated with EHE-related symptoms, with relative risks ranging from high to low. Using an air conditioner during sleep and having a sleep duration of ≥ 6 h were associated with a reduced risk of EHE-related symptoms. The study results suggest that female athletes should be allowed to postpone exercise or reduce its intensity and volume based on their perceptions of dehydration, sickness, loss of appetite, accumulated fatigue, and mental stress in summer to prevent heat-related illnesses.
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Affiliation(s)
- Naoyuki Yamashita
- Faculty of Arts and Sciences, Kyoto Institute of Technology, Kyoto, Japan.
| | - Masashi Kume
- Department of Food and Nutrition, Kyoto Bunkyo Junior College, Uji, Japan
| | - Toshiyuki Satake
- Faculty of Health Science, Kyoto Koka Women's University, Kyoto, Japan
| | - Keiko Inoue
- Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto, Japan
| | - Tetsuya Yoshida
- Faculty of Arts and Sciences, Kyoto Institute of Technology, Kyoto, Japan
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Bernhardt JM, Amiri A. Application of the socioecological model to mitigate risks of heat illness. Nurs Outlook 2024; 72:102150. [PMID: 38442464 DOI: 10.1016/j.outlook.2024.102150] [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: 11/29/2023] [Revised: 02/08/2024] [Accepted: 02/11/2024] [Indexed: 03/07/2024]
Abstract
BACKGROUND The socio-ecological model (SEM) is a widely used framework that can be applied to heat-related illness (HRI) in the context of multiple influencing factors that exist in society. Leaders and policymakers must intervene to mitigate the deleterious effects of climate change on those at risk. PURPOSE The purpose is to introduce the SEM as a framework to address the complex factors contributing to the impact of excess heat. METHODS Conceived through the SEM, the compounding and cumulative impact of excess heat resulting in HRI is operationalized. DISCUSSION The SEM provides a structure for understanding the complex nature of climate change and HRI and proposed interventions. The prevention of HRI is dependent on actions, related to practice, education, research, and advocacy across multiple levels of the SEM. The SEM has the potential to target HRI at all levels of society to reduce the harm of excess heat.
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Affiliation(s)
- Jean M Bernhardt
- School of Nursing, MGH Institute of Health Professions, Charlestown, MA.
| | - Azita Amiri
- College of Nursing, The University of Alabama Huntsville, Huntsville, AL
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Zand S, Motlagh MS, Golmohammadi R, Aliabadi M, Tapak L, Babamiri M. Effects of wearing medical gowns at different temperatures on the physiological responses of female healthcare workers during the COVID-19 pandemic. Work 2024; 78:601-612. [PMID: 38339951 DOI: 10.3233/wor-230360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024] Open
Abstract
BACKGROUND Using medical gowns with high protection against COVID-19 among healthcare workers (HCWs) may limit heat exchange, resulting in physiological challenges. OBJECTIVE This study aimed to compare the physiological and neurophysiological responses of female HCWs when using two typical medical gowns at different temperatures during the COVID-19 pandemic. METHODS Twenty healthy female HCWs participated in this study. Participants wore two types of medical gowns: Spunbond gown (SG) and laminate gown (LG). They walked on a treadmill in a controlled climate chamber for 30 minutes at three different temperatures (24, 28, and 32°C). Heart rate (HR), skin surface temperature (ST), clothing surface temperature (CT), ear temperature (ET), blood oxygen percentage (SaO2), galvanic skin response (GSR), and blood pressure were measured before and after walking on a treadmill. The study's results were analyzed using SPSS26. RESULTS The study found that LG led to an average increase of 0.575°C in CT compared to SG at the same temperatures (P < 0.03). The average HR increased by 6.5 bpm in LG at 28°C compared to SG at a comfortable temperature (P = 0.01). The average ET in SG and GSR in LG at 32°C increased by 0.39°C and 0.25μS, respectively, compared to the comfortable temperature (P < 0.02). CONCLUSION The study recommends maintaining a comfortable temperature range in hospitals to prevent physiological challenges among HCWs wearing medical gowns with high protection against COVID-19. This is important because using LG, compared to SG, at high temperatures can increase HR, ET, CT, and GSR.
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Affiliation(s)
- Sepideh Zand
- Center of Excellence for Occupational Health, Occupational Health and Safety Research Center, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Masoud Shafiee Motlagh
- Center of Excellence for Occupational Health, Occupational Health and Safety Research Center, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rostam Golmohammadi
- Center of Excellence for Occupational Health, School of Public Health and Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohsen Aliabadi
- Center of Excellence for Occupational Health, Occupational Health and Safety Research Center, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Leili Tapak
- Department of Biostatistics, School of Public Health and Modeling of Noncommunicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohammad Babamiri
- Department of Ergonomics, School of Public Health and Research Center for Health Sciences, Hamadan University of Medical Sciences, Hamadan, Iran
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Verdegaal ELJMM, Howarth GS, McWhorter TJ, Delesalle CJG. Thermoregulation during Field Exercise in Horses Using Skin Temperature Monitoring. Animals (Basel) 2023; 14:136. [PMID: 38200867 PMCID: PMC10777899 DOI: 10.3390/ani14010136] [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: 11/29/2023] [Revised: 12/24/2023] [Accepted: 12/26/2023] [Indexed: 01/12/2024] Open
Abstract
Hyperthermia and exertional heat illness (EHI) are performance and welfare issues for all exercising horses. Monitoring the thermoregulatory response allows for early recognition of metabolic heat accumulation during exercise and the possibility of taking prompt and effective preventative measures to avoid a further increase in core body temperature (Tc) leading to hyperthermia. Skin temperature (Tsk) monitoring is most used as a non-invasive tool to assess the thermoregulatory response pre- and post-exercise, particularly employing infrared thermographic equipment. However, only a few studies have used thermography to monitor skin temperature continuously during exercise. This commentary provides an overview of studies investigating surface skin temperature mainly by infrared thermography (IRT) during exercise. The scientific evidence, including methodologies, applications, and challenges associated with (continuous) skin temperature monitoring in horses during field exercise, is discussed. The commentary highlights that, while monitoring Tsk is straightforward, continuous Tsk alone does not always reliably estimate Tc evolvement during field exercise. In addition, inter-individual differences in thermoregulation need to be recognized and accounted for to optimize individual wellbeing. With the ongoing development and application of advanced wearable monitoring technology, there may be future advances in equipment and modeling for timely intervention with horses at hyperthermic risk to improve their welfare. However, at this point, infrared thermographic assessment of Tsk should always be used in conjunction with other clinical assessments and veterinary examinations for a reliable monitoring of the welfare of the horse.
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Affiliation(s)
- Elisabeth-Lidwien J. M. M. Verdegaal
- Thermoregulation Research Group, Equine Health and Performance Centre, University of Adelaide, Roseworthy, SA 5116, Australia; (G.S.H.); (T.J.M.); (C.J.G.D.)
- School of Animal and Veterinary Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, SA 5371, Australia
- Research Group of Comparative Physiology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
| | - Gordon S. Howarth
- Thermoregulation Research Group, Equine Health and Performance Centre, University of Adelaide, Roseworthy, SA 5116, Australia; (G.S.H.); (T.J.M.); (C.J.G.D.)
- School of Animal and Veterinary Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Todd J. McWhorter
- Thermoregulation Research Group, Equine Health and Performance Centre, University of Adelaide, Roseworthy, SA 5116, Australia; (G.S.H.); (T.J.M.); (C.J.G.D.)
- School of Animal and Veterinary Sciences, Roseworthy Campus, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Catherine J. G. Delesalle
- Thermoregulation Research Group, Equine Health and Performance Centre, University of Adelaide, Roseworthy, SA 5116, Australia; (G.S.H.); (T.J.M.); (C.J.G.D.)
- Research Group of Comparative Physiology, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium
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Yeoh CW, Law WC. A case report of near-missed heat stroke. Medicine (Baltimore) 2023; 102:e36676. [PMID: 38134114 PMCID: PMC10735119 DOI: 10.1097/md.0000000000036676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/24/2023] [Indexed: 12/24/2023] Open
Abstract
RATIONALE Heat-related illnesses have protean manifestations that can mimic other life-threatening conditions. The diagnosis of heat stroke requires a high index of suspicion if the patient has been exposed to a high-temperature environment. Central nervous system dysfunction is a cardinal feature. Strict adherence to temperature criteria can potentially lead to misdiagnosis. PATIENT CONCERNS A 37-year-old construction worker was brought in by his wife and coworker due to a sudden loss of consciousness while resting after completing his work. DIAGNOSES Due to challenges faced during the coronavirus disease 2019 pandemic, as well as language barriers, a detailed history from the coworker who witnessed the patient's altered sensorium was not available. He was initially suspected of having encephalitis and brainstem stroke. However, subsequent investigations revealed multiorgan dysfunction with a normal brain computed tomography and cerebral computed tomography angiogram. In view of the multiple risk factors for heat stroke, pupillary constriction, and urine color suggestive of rhabdomyolysis, a diagnosis of heat stroke was made. INTERVENTIONS Despite delayed diagnosis, the patient's multiorgan dysfunction recovered within days with basic supportive care. OUTCOMES There were no noticeable complications on follow-up 14 months later. LESSONS Heat stroke can be easily confused with other neurological pathologies, particularly if no history can be obtained from the patient or informant. When approaching a comatose patient, we propose that serum creatinine kinase should be considered as an initial biochemical screening test.
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Affiliation(s)
- Cheng Wooi Yeoh
- Department of Medicine, Faculty of Medicine and Health Sciences, University of Malaysia Sarawak, Jalan Datuk Mohammad Musa, Kota Samarahan, Sarawak, Malaysia
- Department of Medicine, Sarawak General Hospital, Jalan Hospital, Kuching, Sarawak, Malaysia
| | - Wan Chung Law
- Department of Medicine, Sarawak General Hospital, Jalan Hospital, Kuching, Sarawak, Malaysia
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Ogden HB, Rawcliffe AJ, Delves SK, Roberts A. Are young military personnel at a disproportional risk of heat illness? BMJ Mil Health 2023; 169:559-564. [PMID: 35241622 PMCID: PMC10715519 DOI: 10.1136/bmjmilitary-2021-002053] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/08/2022] [Indexed: 11/04/2022]
Abstract
Heat illnesses (HI) define a continuum of conditions where patients become incapacitated due to uncompensable heat stress. In the military, HI has a significant health, financial and operational burden that requires vigilant management. Military training and operations regularly expose personnel to known HI risk factors, meaning that prevalence remains high despite stringent attempts to reduce risk to as low as reasonably practicable. While prepubertal children and elderly adults are widely demonstrated to be at greater risk of classic HI than young adults due to impaired physiological and/or behavioural thermoregulation, in military personnel, it is young recruit-age individuals (16-19 years) who consistently experience the highest prevalence of exertional HI. Mechanistically, controlled laboratory studies have never directly compared thermoregulation between young recruit-age individuals and other groups of adults, though research highlighting impaired thermoregulation in prepubertal children potentially has some relevance to late-developing young recruit-age personnel. Aside from potential age-related differences in thermoregulation, a major consideration must also be given to the increased prevalence of organisational risk factors for HI in younger military personnel (eg, education, physical load, rank, job roles), which is likely to be the primary explanation behind age-related trends in HI prevalence, at least in the military. The aims of this article are to review: (i) the epidemiology of HI between young recruit-age individuals and older military personnel; (ii) the theoretical basis for age-associated differences in thermoregulatory function and (iii) pertinent areas for future research.
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Affiliation(s)
- Henry B Ogden
- Army Recruit Health and Performance Research, UK Ministry of Defence, Upavon, Wiltshire, UK
| | - A J Rawcliffe
- Army Recruit Health and Performance Research, UK Ministry of Defence, Upavon, Wiltshire, UK
| | - S K Delves
- Environmental Medicine and Science, Institute of Naval Medicine, Gosport, UK
| | - A Roberts
- Army Recruit Health and Performance Research, UK Ministry of Defence, Upavon, Wiltshire, UK
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Buller MJ, Atkinson E, Driver K, Tharion WJ, Ely BR, Cheuvront SN, Charkoudian N. Individualized monitoring of heat illness risk: novel adaptive physiological strain index to assess exercise-heat strain from athletes to fully encapsulated workers. Physiol Meas 2023; 44:10NT01. [PMID: 37703905 DOI: 10.1088/1361-6579/acf991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 09/13/2023] [Indexed: 09/15/2023]
Abstract
Objective. Exercise-heat strain estimation approaches often involve combinations of body core temperature (Tcore), skin temperature (Tsk) and heart rate (HR). A successful existing measure is the 'Physiological Strain Index' (PSI), which combines HR and Tcore values to estimate strain. However, depending on variables such as aerobic fitness and clothing, the equation's 'maximal/critical' Tcore must be changed to accurately represent the strain, in part because high Tsk (small Tcore-Tsk) can increase cardiovascular strain and thereby negatively affect performance. Here, an 'adaptive PSI' (aPSI) is presented where the original PSI Tcorecriticalvalue is 'adapted' dynamically by the delta between Tcore and Tsk.Approach. PSI and aPSI were computed for athletes (ELITE,N= 11 male and 8 female, 8 km time-trial) and soldiers in fully encapsulating personal protective equipment (PPE,N= 8 male, 2 km approach-march). While these were dissimilar events, it was anticipated given that the clothing and work rates would elicit similar very-high exercise-heat strain values.Main results. Mean end HR values were similar (∼180 beats min-1) with higher Tcore = 40.1 ± 0.4 °C for ELITE versus PPE 38.4 ± 0.6 °C (P< 0.05). PSI end values were different between groups (P< 0.01) and appeared 'too-high' for ELITE (11.4 ± 0.8) and 'too-low' for PPE (7.6 ± 2.0). However, aPSI values were not different (9.9 ± 1.4 versus 9.0 ± 2.5 versus;p> 0.05) indicating a 'very high' level of exercise-heat strain for both conditions.Significance. A simple adaptation of the PSI equation, which accounts for differences in Tcore-to-Tsk gradients, provides a physiological approach to dynamically adapt PSI to provide a more accurate index of exercise-heat strain under very different working conditions.
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Affiliation(s)
- Mark J Buller
- US Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Natick, MA 01760, United States of America
| | - Emma Atkinson
- US Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Natick, MA 01760, United States of America
| | - Kyla Driver
- US Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Natick, MA 01760, United States of America
| | - William J Tharion
- US Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Natick, MA 01760, United States of America
| | - Brett R Ely
- Department of Health Sciences, Providence College, Providence, RI 02918, United States of America
| | - Samuel N Cheuvront
- Sports Science Synergy, LLC, Franklin, MA 02038, United States of America
| | - Nisha Charkoudian
- US Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Natick, MA 01760, United States of America
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Fujimoto M, Hayashi K, Nishiura H. Possible adaptation measures for climate change in preventing heatstroke among older adults in Japan. Front Public Health 2023; 11:1184963. [PMID: 37808973 PMCID: PMC10556232 DOI: 10.3389/fpubh.2023.1184963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/07/2023] [Indexed: 10/10/2023] Open
Abstract
Introduction Heatstroke mortality is highest among older adults aged 65 years and older, and the risk is even doubled among those aged 75 years and older. The incidence of heatstroke is expected to increase in the future with elevated temperatures owing to climate change. In the context of a super-aged society, we examined possible adaptation measures in Japan that could prevent heatstroke among older people using an epidemiological survey combined with mathematical modeling. Methods To identify possible interventions, we conducted a cross-sectional survey, collecting information on heatstroke episodes from 2018 to 2019 among people aged 75 years and older. Responses were analyzed from 576 participants, and propensity score matching was used to adjust for measurable confounders and used to estimate the effect sizes associated with variables that constitute possible interventions. Subsequently, a weather-driven statistical model was used to predict heatstroke-related ambulance transports. We projected the incidence of heatstroke-related transports until the year 2100, with and without adaptation measures. Results The risk factor with the greatest odds ratio (OR) of heatstroke among older adults was living alone (OR 2.5, 95% confidence interval: 1.2-5.4). Other possible risk factors included an inability to drink water independently and the absence of air conditioning. Using three climate change scenarios, a more than 30% increase in the incidence of heatstroke-related ambulance transports was anticipated for representative concentration pathways (RCP) 4.5 and 8.5, as compared with a carbon-neutral scenario. Given 30% reduction in single living, a 15% reduction in the incidence of heatstroke is expected. Given 70% improvement in all three risk factors, a 40% reduction in the incidence can be expected. Conclusion Possible adaptation measures include providing support for older adults living alone, for those who have an inability to drink water and for those without air conditioning. To be comparable to carbon neutrality, future climate change under RCP 2.6 requires achieving a 30% relative reduction in all three identified risks at least from 2060; under RCP 4.5, a 70% reduction from 2050 at the latest is needed. In the case of RCP 8.5, the goal of heatstroke-related transports approaching RCP 1.9 cannot be achieved.
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Kruijt N, van den Bersselaar LR, Hopman MTE, Snoeck MMJ, van Rijswick M, Wiggers TGH, Jungbluth H, Bongers CCWG, Voermans NC. Exertional Heat Stroke and Rhabdomyolysis: A Medical Record Review and Patient Perspective on Management and Long-Term Symptoms. SPORTS MEDICINE - OPEN 2023; 9:33. [PMID: 37204519 DOI: 10.1186/s40798-023-00570-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 04/19/2023] [Indexed: 05/20/2023]
Abstract
INTRODUCTION Exertional heat stroke (EHS) is a medical emergency, occurring when the body generates more heat than it can dissipate, and frequently associated with exertional rhabdomyolysis (ERM). In the present study we aimed to (I) identify clinical features and risk factors, (II) describe current prehospital management, (III) investigate long-term outcomes including the impact on mental health, and review the guidance received during restarting activities. We hope that our approach will improve individual and organizational heat illness preparedness, and improve follow-up care. METHODS We performed a prospective online survey and retrospective medical record review among athletes and military personnel with an episode of EHS/ERM in the Netherlands between 2010 and 2020. We evaluated prehospital management, risk factors, clinical features and long-term outcomes at 6 and 12 months after the event, including mental health symptoms. Furthermore, we investigated what guidance participants received during follow-up, and assessed the patients' perspective on these outcomes. RESULTS Sixty participants were included, 42 male (70%) and 18 female (30%), of which 47 presented with EHS (78%) and 13 with ERM (22%). Prehospital management was inconsistent and in the majority of participants not conducted according to available guidelines. Self-reported risk factors included not feeling well-acclimatized to environmental heat (55%) and peer pressure (28%). Self-reported long-term symptoms included muscle symptoms at rest (26%) or during exercise (28%), and neurological sequelae (11%). Validated questionnaires (CIS, HADS and SF-36) were indicative of severe fatigue (30%) or mood/anxiety disorders (11%). Moreover, 90% expressed a lack of follow-up care and that a more frequent and intensive follow-up would have been beneficial for their recovery process. CONCLUSION Our findings indicate major inconsistencies in the management of patients with EHS/ERM, emphasizing the compelling need for implementing standardized protocols. Based on the results of long-term outcome measures, we recommend to counsel and evaluate every patient not only immediately after the event, but also in the long-term.
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Affiliation(s)
- Nick Kruijt
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Geert Grooteplein 10 (Route 652), 6525 GA, Nijmegen, The Netherlands.
- Department of Primary and Community Care, Radboudumc, Nijmegen, The Netherlands.
| | - L R van den Bersselaar
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Geert Grooteplein 10 (Route 652), 6525 GA, Nijmegen, The Netherlands
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
| | - M T E Hopman
- Department of Physiology, Radboudumc, Nijmegen, The Netherlands
| | - M M J Snoeck
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
| | - M van Rijswick
- Department of Exercise Medicine and Exercise Physiology, Royal Dutch Army, Utrecht, The Netherlands
| | - T G H Wiggers
- Department of Sports Medicine, Anna Hospital, Geldrop, The Netherlands
| | - H Jungbluth
- Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | - C C W G Bongers
- Department of Physiology, Radboudumc, Nijmegen, The Netherlands
| | - N C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Geert Grooteplein 10 (Route 652), 6525 GA, Nijmegen, The Netherlands
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DeHan PJ, Warren KC, Buchanan BK, DeGroot DW. Gastrointestinal Associated Exertional Heat Stroke. Curr Sports Med Rep 2023; 22:117-119. [PMID: 37036459 DOI: 10.1249/jsr.0000000000001054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Affiliation(s)
- Preston J DeHan
- Martin Army Community Hospital Family Medicine Residency Program; Fort Benning, GA
| | - Kyle C Warren
- Martin Army Community Hospital Family Medicine Residency Program; Fort Benning, GA
| | - Benjamin K Buchanan
- Department of Family Medicine Uniformed Services University of the Health Sciences; Core Faculty, Martin Army Community Hospital Family Medicine Residency Program; Deputy Director, The Army Heat Center, Fort Benning, GA
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Yamashita N, Kume M, Satake T, Yoshida T. Subjective perceived risk factors of exertional heat exhaustion-related symptoms in male collegiate athletes in Japan: a case-control study. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2023; 67:649-659. [PMID: 36840761 DOI: 10.1007/s00484-023-02442-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 02/09/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
The purpose of this study was to investigate associations between lifestyle habits, health factors, athletic activity conditions, and exertional heat exhaustion (EHE)-related symptoms among male college athletes in Japan based on a self-completed questionnaire. The paper-based questionnaires were distributed to 11 universities in Japan, and 2006 respondents completed the survey. Data of personal characteristics (age, body mass), lifestyle habits (sleep duration, use of air-conditioner while sleeping, and practice duration), perceived health factors (loss of appetite, sleep deprivation, sickness, dehydration, accumulated fatigue, and mental stress), perceived athletic activity (insufficient rest breaks, high ambient temperature, excessive humidity, strong solar radiation, lack of ambient wind, and clothing discomfort), and EHE-related symptoms (dizziness, headaches, nausea, and malaise) were collected. The association between lifestyle habits, health factors, athletic activity conditions (explanatory variables), and EHE-related symptoms (objective variables) was analyzed using the partial-proportional odds model. "Perceived dehydration" (odds ratios [ORs] 1.70-2.31, p < 0.002)," "sickness" (ORs 1.35-1.76), p < 0.001), "perceived accumulated fatigue" (ORs 1.13-1.31, p ≤ 0.001), "perceived mental stress" (ORs 1.17-1.31, p < 0.019), "lack of ambient wind" (ORs 1.12-1.19, p < 0.022), "loss of appetite" (ORs 1.16-1.23, p < 0.037), and "sleep deprivation" (ORs 1.15-1.17, p < 0.025) were positively associated with EHE-related symptoms, whereas "using an air conditioner during sleeping" (ORs 0.91, p = 0.047) during summer seasons was negatively associated. These findings suggest that athletes should be allowed to postpone or downregulate exercise intensity and/or volume based on their perceptions of dehydration, sickness, accumulated fatigue, mental stress, loss of appetite, and/or sleep deprivation in the summer to prevent heat illness.
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Affiliation(s)
- Naoyuki Yamashita
- Faculty of Arts and Sciences, Kyoto Institute of Technology, 1 Hashikamicho Matsugasaki Sakyoku, Kyoto, 606-8585, Japan.
| | - Masashi Kume
- Department of Food and Nutrition, Kyoto Bunkyo Junior College, Uji, Japan
| | - Toshiyuki Satake
- Faculty of Health Science, Kyoto Koka Women's University, Kyoto, Japan
| | - Tetsuya Yoshida
- Faculty of Arts and Sciences, Kyoto Institute of Technology, 1 Hashikamicho Matsugasaki Sakyoku, Kyoto, 606-8585, Japan
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Liu S, Wen D, Feng C, Yu C, Gu Z, Wang L, Zhang Z, Li W, Wu S, Liu Y, Duan C, Zhuang R, Xue L. Alteration of gut microbiota after heat acclimation may reduce organ damage by regulating immune factors during heat stress. Front Microbiol 2023; 14:1114233. [PMID: 36910226 PMCID: PMC9995595 DOI: 10.3389/fmicb.2023.1114233] [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: 12/02/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Introduction Heat-related illnesses can lead to morbidity, which are anticipated to increase frequency with predictions of increased global surface temperatures and extreme weather events. Although heat acclimation training (HAT) could prevent heat-related diseases, the mechanisms underlying HAT-promoting beneficial changes in organ function, immunity, and gut microbes remain unclear. Methods In the current study, we recruited 32 healthy young soldiers and randomly divided them into 4 teams to conduct HATs for 10 days: the equipment-assisted training team at high temperature (HE); the equipment-assisted training team under normal hot weather (NE); the high-intensity interval training team at high temperature (HIIT), and the control team without training. A standard heat tolerance test (HTT) was conducted before (HTT-1st) and after (HTT-2nd) the training to judge whether the participants met the heat acclimation (HA) criteria. Results We found that the participants in both HE and NE teams had significantly higher acclimation rates (HA/total population) than whom in the HIIT team. The effects of HAT on the participants of the HE team outperformed that of the NE team. In the HA group, the differences of physiological indicators and plasma organ damage biomarkers (ALT, ALP, creatinine, LDH, α-HBDH and cholinesterase) before and after HTT-2nd were significantly reduced to those during HTT-1st, but the differences of immune factors (IL-10, IL-6, CXCL2, CCL4, CCL5, and CCL11) elevated. The composition, metabolism, and pathogenicity of gut microbes changed significantly, with a decreased proportion of potentially pathogenic bacteria (Escherichia-Shigella and Lactococcus) and increased probiotics (Dorea, Blautia, and Lactobacillus) in the HA group. Training for a longer time in a high temperature and humidity showed beneficial effects for intestinal probiotics. Conclusion These findings revealed that pathogenic gut bacteria decrease while probiotics increase following HA, with elevated immune factors and reduced organ damage during heat stress, thereby improving the body's heat adaption.
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Affiliation(s)
- Shanshou Liu
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Dongqing Wen
- Air Force Medical Center, Fourth Military Medical University, Beijing, China
| | - Chongyang Feng
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chaoping Yu
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zhao Gu
- Air Force Medical Center, Fourth Military Medical University, Beijing, China
| | - Liping Wang
- Air Force Medical Center, Fourth Military Medical University, Beijing, China
| | - Zhixiang Zhang
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Wenpeng Li
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Shuwen Wu
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yitian Liu
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chujun Duan
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ran Zhuang
- Department of Immunology, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Lihao Xue
- Air Force Medical Center, Fourth Military Medical University, Beijing, China
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13
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Brownlow MA, Mizzi JX. Pathophysiology of exertional heat illness in the Thoroughbred racehorse: Broadening perspective to include an exercise‐induced gastrointestinal syndrome in which endotoxaemia and systemic inflammation may contribute to the condition. EQUINE VET EDUC 2022. [DOI: 10.1111/eve.13750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - James Xavier Mizzi
- Department of Regulation, Welfare and Biosecurity Policy The Hong Kong Jockey Club, Sha Tin Racecourse Sha Tin Hong Kong
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14
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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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15
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Lee JKW, Tan B, Ogden HB, Chapman S, Sawka MN. Exertional heat stroke: nutritional considerations. Exp Physiol 2022; 107:1122-1135. [PMID: 35521757 PMCID: PMC9790308 DOI: 10.1113/ep090149] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/02/2022] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the topic of this review? The potential role of nutrition in exertional heat stroke. What advances does it highlight? Certain nutritional and dietary strategies used by athletes and workers may exert a protective effect the pathophysiological processes of exertional heat stroke, whereas others may be detrimental. While current evidence suggests that some of these practices may be leveraged as a potential countermeasure to exertional heat stroke, further research on injury-related outcomes in humans is required. ABSTRACT Exertional heat stroke (EHS) is a life-threatening illness and an enduring problem among athletes, military servicemen and -women, and occupational labourers who regularly perform strenuous activity, often under hot and humid conditions or when wearing personal protective equipment. Risk factors for EHS and mitigation strategies have generally focused on the environment, health status, clothing, heat acclimatization and aerobic conditioning, but the potential role of nutrition is largely underexplored. Various nutritional and dietary strategies have shown beneficial effects on exercise performance and health and are widely used by athletes and other physically active populations. There is also evidence that some of these practices may dampen the pathophysiological features of EHS, suggesting possible protection or abatement of injury severity. Promising candidates include carbohydrate ingestion, appropriate fluid intake and glutamine supplementation. Conversely, some nutritional factors and low energy availability may facilitate the development of EHS, and individuals should be cognizant of these. Therefore, the aims of this review are to present an overview of EHS along with its mechanisms and pathophysiology, discuss how selected nutritional considerations may influence EHS risk focusing on their impact on the key pathophysiological processes of EHS, and provide recommendations for future research. With climate change expected to increase EHS risk and incidence in the coming years, further investigation on how diet and nutrition may be optimized to protect against EHS would be highly beneficial.
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Affiliation(s)
- Jason K. W. Lee
- Human Potential Translational Research Program, Yong Loo Lin School of MedicineNational University of SingaporeSingapore,Heat Resilience and Performance Centre, Yong Loo Lin School of MedicineNational University of SingaporeSingapore,Department of Physiology, Yong Loo Lin School of MedicineNational University of SingaporeSingapore,N.1 Institute for HealthNational University of SingaporeSingapore,Global Asia InstituteNational University of SingaporeSingapore,Institute for Digital MedicineYong Loo Lin School of MedicineNational University of SingaporeSingapore,Singapore Institute for Clinical SciencesAgency for Science, Technology and Research (A*STAR)Singapore,Campus for Research Excellence and Technological Enterprise (CREATE)SingaporeSingapore
| | - Beverly Tan
- Human Potential Translational Research Program, Yong Loo Lin School of MedicineNational University of SingaporeSingapore,Campus for Research Excellence and Technological Enterprise (CREATE)SingaporeSingapore
| | - Henry B. Ogden
- Army Recruit Health and Performance ResearchHeadquarters of Army Recruiting and Initial Training Command, UpavonPewseyUK,Department of Sport, Health and WellbeingPlymouth Marjon UniversityPlymouthUK
| | - Shaun Chapman
- Army Recruit Health and Performance ResearchHeadquarters of Army Recruiting and Initial Training Command, UpavonPewseyUK,Cambridge Centre for Sport and Exercise SciencesSchool of Psychology and Sport ScienceAnglia Ruskin UniversityCambridgeUK
| | - Michael N. Sawka
- School of Biological SciencesGeorgia Institute of TechnologyAtlantaGAUSA
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16
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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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17
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Riazi S, Bersselaar LRVD, Islander G, Heytens L, Snoeck MMJ, Bjorksten A, Gillies R, Dranitsaris G, Hellblom A, Treves S, Kunst G, Voermans NC, Jungbluth H. Pre-operative exercise and pyrexia as modifying factors in malignant hyperthermia (MH). Neuromuscul Disord 2022; 32:628-634. [PMID: 35738978 DOI: 10.1016/j.nmd.2022.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022]
Abstract
Malignant hyperthermia (MH) is a life-threatening reaction triggered by volatile anesthetics and succinylcholine. MH is caused by mutations in the skeletal muscle ryanodine receptor (RYR1) gene, as is rhabdomyolysis triggered by exertion and/or pyrexia. The discrepancy between the prevalence of risk genotypes and actual MH incidence remains unexplained. We investigated the role of pre-operative exercise and pyrexia as potential MH modifying factors. We included cases from 5 MH referral centers with 1) clinical features suggestive of MH, 2) confirmation of MH susceptibility on Contracture Testing (IVCT or CHCT) and/or RYR1 genetic testing, and a history of 3) strenuous exercise within 72 h and/or pyrexia >37.5 °C prior to the triggering anesthetic. Characteristics of MH-triggering agents, surgery and succinylcholine use were collected. We identified 41 cases with general anesthesias resulting in an MH event (GA+MH, n = 41) within 72 h of strenuous exercise and/or pyrexia. We also identified previous general anesthesias without MH events (GA-MH, n = 51) in the index cases and their MH susceptible relatives. Apart from pre-operative exercise and/or pyrexia, trauma and acute abdomen as surgery indications, emergency surgery and succinylcholine use were also more common with GA+MH events. These observations suggest a link between pre-operative exercise, pyrexia and MH.
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Affiliation(s)
- Sheila Riazi
- Department of Anesthesia, Malignant Hyperthermia Investigation Unit, University Health Network, University of Toronto, Toronto, Canada
| | | | | | - Luc Heytens
- Department of Anaesthesiology, University Hospital Antwerp, Edegem, Belgium
| | - Marc M J Snoeck
- Malignant Hyperthermia Investigation Unit, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
| | - Andrew Bjorksten
- Department of Anaesthesia and Pain Management, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Robyn Gillies
- Department of Anaesthesia and Pain Management, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - George Dranitsaris
- Department of Anesthesia, Malignant Hyperthermia Investigation Unit, University Health Network, University of Toronto, Toronto, Canada
| | - Anna Hellblom
- Department of Intensive and Perioperative Medicine, Skane University Hospital, Lund, Sweden; Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Susan Treves
- Department of Biomedicine, Basel University Hospital, Basel University, Basel, Switzerland
| | - Gudrun Kunst
- Department of Anaesthetics and Pain Therapy, King's College Hospital, London, UK; School of Cardiovascular Medicine and Sciences, King's College London, London, UK
| | - Nicol C Voermans
- Department of Neurology, Radboud University, Nijmegen, The Netherlands
| | - Heinz Jungbluth
- Randall Centre Cell and Molecular Biophysics, Muscle Signalling Section, King's College, London, UK; Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, UK.
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18
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Verdegaal ELJMM, Howarth GS, McWhorter TJ, Delesalle CJG. Is Continuous Monitoring of Skin Surface Temperature a Reliable Proxy to Assess the Thermoregulatory Response in Endurance Horses During Field Exercise? Front Vet Sci 2022; 9:894146. [PMID: 35711810 PMCID: PMC9196037 DOI: 10.3389/fvets.2022.894146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Hyperthermia is a performance and welfare issue for exercising horses. The thermoregulatory stressors associated with exercise have typically been estimated by responses in the laboratory. However, monitoring surface skin temperature (Tsk) coincident with core temperature (Tc) has not previously been investigated in horses exercising in the field. We investigated the suitability of monitoring surface Tsk as a metric of the thermoregulatory response, and simultaneously investigated its relationship with Tc using gastrointestinal (GI) temperature. We evaluated Tsk in 13 endurance horses competing during four endurance rides over 40 km (n = 1) or a total of 80 km (n = 12) distance. Following each 40-km loop, the horses were rested for 60 min. Tsk and Tc were continuously recorded every 15 s by an infrared thermistor sensor located in a modified belt and by telemetric GI pill, respectively, and expressed as mean ± SD. The net area under the curve (AUC) was calculated to estimate the thermoregulatory response to the thermal load of Tsk over time (°C × minutes) using the trapezoidal method. The relationship between Tsk and Tc was assessed using scatterplots, paired t-test or generalized linear model ANOVA (delta Tsk) (n = 8). Ambient temperature ranged from 6.7°C to 18.4°C. No relationship was found between Tsk and Tc profiles during exercise and recovery periods, and no significant difference between delta Tsk results was detected when comparing exercise and rest. However, time to maximum Tsk (67 min) was significantly reduced compared to Tc (139 min) (p = 0.0004) with a significantly lesser maximum Tsk (30.3°C) than Tc (39°C) (p = 0.0002) during exercise. Net AUC Tsk was 1,164 ± 1,448 and −305 ± 388°C × minutes during periods of exercise and recovery, respectively. We conclude that Tsk monitoring does not provide a reliable proxy for the thermoregulatory response and horse welfare, most probably because many factors can modulate Tsk without directly affecting Tc. Those factors, such as weather conditions, applicable to all field studies can influence the results of Tsk in endurance horses. The study also reveals important inter-individual differences in Tsk and Tc time profiles, emphasizing the importance of an individualized model of temperature monitoring.
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Affiliation(s)
- Elisabeth-Lidwien J. M. M. Verdegaal
- Equine Health and Performance Centre, University of Adelaide, Adelaide, SA, Australia
- Department of Translational Physiology, Infectiology and Public Health, Research Group of Comparative Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- *Correspondence: Elisabeth-Lidwien J. M. M. Verdegaal
| | - Gordon S. Howarth
- Equine Health and Performance Centre, University of Adelaide, Adelaide, SA, Australia
- Gastroenterology Department, Women's and Children's Hospital, Adelaide, SA, Australia
| | - Todd J. McWhorter
- Equine Health and Performance Centre, University of Adelaide, Adelaide, SA, Australia
| | - Catherine J. G. Delesalle
- Department of Translational Physiology, Infectiology and Public Health, Research Group of Comparative Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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19
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Brownlow M, Mizzi JX. Epidemiology of exertional heat illness in Thoroughbred racehorses in temperate eastern Australia: The role of extrinsic (environmental) factors in disease causation. EQUINE VET EDUC 2022. [DOI: 10.1111/eve.13627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Brownlow
- Racing Australia Sydney New South Wales Australia
| | - J. X. Mizzi
- Department of Regulation, Welfare and Biosecurity Policy The Hong Kong Jockey Club, Sha Tin Racecourse Hong Kong Sha Tin China
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20
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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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21
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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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22
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Ogden HB, Fallowfield JL, Child RB, Davison G, Fleming SC, Delves SK, Millyard A, Westwood CS, Layden JD. Acute L-Glutamine Supplementation does not improve Gastrointestinal Permeability, Injury or Microbial Translocation in Response to Exhaustive High Intensity Exertional-Heat Stress. Eur J Sport Sci 2021; 22:1865-1876. [PMID: 34726114 DOI: 10.1080/17461391.2021.2001575] [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: 12/13/2022]
Abstract
PurposeExertional-heat stress adversely distrupts (GI) barrier integrity and, through subsequent microbial translocation (MT), can result in potentially fatal exertional-heat stroke. Acute glutamine (GLN) supplementation is a potential nutritional countermeasure, although the practical value of current supplementation regimens is questionable. Method: Ten males completed two high-intensity exertional-heat stress tests (EHST) involving running in the heat (40°C and 40% relative humidity) at lactate threshold to volitional exhaustion. Participants ingested GLN (0.3 g·kg·FFM-1) or a non-calorific placebo (PLA) one hour prior to the EHST. Venous blood was drawn pre-, post- and one-hour post-EHST. GI permeability was assessed using a serum dual-sugar absorption test (DSAT) and small intestinal epithelial injury using plasma Intestinal Fatty-Acid Binding Protein (I-FABP). MT was assessed using the Bacteroides/total 16S DNA ratio. Results: Volitional exhaustion occurred after 22:19 ± 2:22 (minutes: seconds) in both conditions, during which whole-body physiological responses and GI symptoms were not different (p ˃ 0.05). GI permeability (serum DSAT) was greater following GLN (0.043 ± 0.020) than PLA (0.034 ± 0.019) (p = 0.02; d = 0.47), but small intestine epithelial injury (I-FABP) increased comparably (p = 0.22; η2p = 0.16) following the EHST in both trials (GLN Δ = 1.25 ± 0.63 ng·ml-1; PLA Δ= 0.92 ± 0.44 ng·ml-1). GI MT (Bacteroides/total 16S DNA ratio) was unchanged in either condition following the EHST (p = 0.43). Conclusion: Acute low-dose (0.3 g·kg-1 fat free mass) GLN supplementation ingested one hour before high-intesity exertional-heat stress worsened GI permeability, but did not influence either small intestinal epithilial injury or microbial translocation.Highlights: The pathophysiology of exertional-heat stroke is widely hypothesised to be at least in part attributable to a systemic inflammatory response caused by the leak of gastrointestinal microbes into the circulating blood.Acute high-dose (0.9 g·kg·FFM-1) L-glutamine supplementation is widely promoted as a practical strategy to protect gastrointestinal barrier integrity during exertional-heat stress. However, previously validated doses are often poorly tolerated and cannot be recommended for widespread implementation.This study examined the efficacy of low-dose (0.30 g·kg·FFM-1; ∼20 grams) acute L-glutamine supplementation on small intestinal injury, permeability, and microbial translocation in response a high-intensity exertional-heat stress test to exhaustion (20 - 30 minutes). This type of exercise accounts for the majority of exertional-heat stroke cases in the military.Despite being universally well-tolerated across all participants, acute low-dose L-glutamine supplementation worsened gastrointestinal permeability, without influencing either small intestinal injury or microbial translocation. These findings do not support the application of low-dose L-glutamine supplementation to help prevent exertional-heat stroke.
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Affiliation(s)
- Henry B Ogden
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
| | | | - Robert B Child
- School of Chemical Engineering, University of Birmingham, Birmingham, United Kingdom
| | - Glen Davison
- Endurance Research Group, School of Sport and Exercise Sciences, University of Kent, Chatham Maritime, United Kingdom
| | | | | | - Alison Millyard
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
| | - Caroline S Westwood
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
| | - Joseph D Layden
- School of Sport, Health and Wellbeing, Plymouth MARJON University, Plymouth, United Kingdom
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Brownlow MA, Brotherhood JR. An investigation into environmental variables influencing post-race exertional heat illness in thoroughbred racehorses in temperate eastern Australia. Aust Vet J 2021; 99:473-481. [PMID: 34355381 DOI: 10.1111/avj.13108] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/30/2022]
Abstract
Exertional heat illness (EHI) is a syndrome that occurs when metabolic heat production from muscular contraction exceeds the rate at which it can be dissipated. Core body temperature rises to critical levels, causing hyperthermia and central nervous system dysfunction. Best practice for the prevention of EHI centres around early detection, rapid response and aggressive cooling. Advance planning enables risk mitigation measures. The more that is known about EHI in horses, the better prepared those in the positions of responsibility can be to anticipate events in which the risk of EHI may be elevated. This prospective, observational study investigated environmental risk factors associated with the occurrence of EHI. From 2014 to 2018, the number of horses exhibiting the symptoms of post-race EHI was recorded at 73 convenience sampled race meetings. Of the 4809 starters, the signs of EHI were recorded for 457. Thermal environmental data were measured and included ambient temperature, radiant heat, vapor pressure (humidity) and wind speed (WS). Mixed linear regression models were computed to assess the associations between the occurrence and incidence of post-race EHI and the four thermal environmental variables. The analysis showed that vapor pressure and WS had the largest effects on the occurrence of post-race EHI. The major limitations were that the race meetings selected were convenience sampled according to attendance by the first author and individual horse data were not available. EHI is influenced by a complex interaction of independently acting environmental variables, but warm, windless, humid days are most likely to result in the cases of EHI.
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Affiliation(s)
- M A Brownlow
- Racing Australia, Druitt Street, Sydney, New South Wales, 2000, Australia
| | - J R Brotherhood
- Discipline of Exercise and Sports Science, School of Health Sciences, Faculty of Medicine and Health, University of Sydney, Australia
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24
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Morrissey MC, Casa DJ, Brewer GJ, Adams WM, Hosokawa Y, Benjamin CL, Grundstein AJ, Hostler D, McDermott BP, McQuerry ML, Stearns RL, Filep EM, DeGroot DW, Fulcher J, Flouris AD, Huggins RA, Jacklitsch BL, Jardine JF, Lopez RM, McCarthy RB, Pitisladis Y, Pryor RR, Schlader ZJ, Smith CJ, Smith DL, Spector JT, Vanos JK, Williams WJ, Vargas NT, Yeargin SW. Heat Safety in the Workplace: Modified Delphi Consensus to Establish Strategies and Resources to Protect the US Workers. GEOHEALTH 2021; 5:e2021GH000443. [PMID: 34471788 PMCID: PMC8388206 DOI: 10.1029/2021gh000443] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/08/2021] [Accepted: 06/11/2021] [Indexed: 06/04/2023]
Abstract
The purpose of this consensus document was to develop feasible, evidence-based occupational heat safety recommendations to protect the US workers that experience heat stress. Heat safety recommendations were created to protect worker health and to avoid productivity losses associated with occupational heat stress. Recommendations were tailored to be utilized by safety managers, industrial hygienists, and the employers who bear responsibility for implementing heat safety plans. An interdisciplinary roundtable comprised of 51 experts was assembled to create a narrative review summarizing current data and gaps in knowledge within eight heat safety topics: (a) heat hygiene, (b) hydration, (c) heat acclimatization, (d) environmental monitoring, (e) physiological monitoring, (f) body cooling, (g) textiles and personal protective gear, and (h) emergency action plan implementation. The consensus-based recommendations for each topic were created using the Delphi method and evaluated based on scientific evidence, feasibility, and clarity. The current document presents 40 occupational heat safety recommendations across all eight topics. Establishing these recommendations will help organizations and employers create effective heat safety plans for their workplaces, address factors that limit the implementation of heat safety best-practices and protect worker health and productivity.
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Affiliation(s)
- Margaret C. Morrissey
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Douglas J. Casa
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Gabrielle J. Brewer
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - William M. Adams
- Department of KinesiologyUniversity of North Carolina at GreensboroGreensboroNCUSA
| | - Yuri Hosokawa
- Faculty of Sports SciencesWaseda UniversitySaitamaJapan
| | | | | | - David Hostler
- Department of Exercise and Nutrition SciencesCenter for Research and Education in Special EnvironmentsBuffaloNYUSA
| | - Brendon P. McDermott
- Department of Health, Human Performance and RecreationUniversity of ArkansasFayettevilleARUSA
| | | | - Rebecca L. Stearns
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Erica M. Filep
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - David W. DeGroot
- Fort Benning Heat CenterMartin Army Community HospitalFort BenningGAUSA
| | | | - Andreas D. Flouris
- Department of Exercise ScienceFAME LaboratoryUniversity of ThessalyTrikalaGreece
| | - Robert A. Huggins
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | | | - John F. Jardine
- Department of KinesiologyKorey Stringer InstituteUniversity of ConnecticutMansfieldCTUSA
| | - Rebecca M. Lopez
- School of Physical Therapy & Rehabilitation SciencesMorsani College of MedicineUniversity of South FloridaTampaFLUSA
| | | | - Yannis Pitisladis
- Collaborating Centre of Sports MedicineUniversity of BrightonBrightonUK
| | - Riana R. Pryor
- Department of Exercise and Nutrition SciencesCenter for Research and Education in Special EnvironmentsBuffaloNYUSA
| | - Zachary J. Schlader
- Department of KinesiologySchool of Public HealthIndiana UniversityBloomingtonIAUSA
| | - Caroline J. Smith
- Department of Health and Exercise ScienceAppalachian State UniversityBooneNCUSA
| | - Denise L. Smith
- Department of Health and Human Physiological SciencesFirst Responder Health and Safety LaboratorySkidmore CollegeSaratoga SpringsNYUSA
| | - June T. Spector
- Department of Environmental and Occupational Health SciencesSchool of Public HealthUniversity of WashingtonSeattleWAUSA
| | | | - W. Jon Williams
- Centers for Disease Control and Prevention (CDC)National Personal Protective Technology Laboratory (NPPTL)National Institute for Occupational Safety and Health (NIOSH)PittsburghPAUSA
| | - Nicole T. Vargas
- Faculty of Health SciencesUniversity of SydneySydneyNSWAustralia
| | - Susan W. Yeargin
- Department of Exercise ScienceArnold School of Public HealthUniversity of South CarolinaColumbiaSCUSA
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25
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Zhang ZT, Gu XL, Zhao X, He X, Shi HW, Zhang K, Zhang YM, Su YN, Zhu JB, Li ZW, Li GB. NLRP3 ablation enhances tolerance in heat stroke pathology by inhibiting IL-1β-mediated neuroinflammation. J Neuroinflammation 2021; 18:128. [PMID: 34092247 PMCID: PMC8182902 DOI: 10.1186/s12974-021-02179-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/19/2021] [Indexed: 11/10/2022] Open
Abstract
Background Patients with prior illness are more vulnerable to heat stroke-induced injury, but the underlying mechanism is unknown. Recent studies suggested that NLRP3 inflammasome played an important role in the pathophysiology of heat stroke. Methods In this study, we used a classic animal heat stroke model. Prior infection was mimicked by using lipopolysaccharide (LPS) or lipoteichoic acid (LTA) injection before heat stroke (LPS/LTA 1 mg/kg). Mice survival analysis curve and core temperature (TC) elevation curve were produced. NLRP3 inflammasome activation was measured by using real-time PCR and Western blot. Mice hypothalamus was dissected and neuroinflammation level was measured. To further demonstrate the role of NLRP3 inflammasome, Nlrp3 knockout mice were used. In addition, IL-1β neutralizing antibody was injected to test potential therapeutic effect on heat stroke. Results Prior infection simulated by LPS/LTA injection resulted in latent inflammation status presented by high levels of cytokines in peripheral serum. However, LPS/LTA failed to cause any change in animal survival rate or body temperature. In the absence of LPS/LTA, heat treatment induced heat stroke and animal death without significant systemic or neuroinflammation. Despite a decreased level of IL-1β in hypothalamus, Nlrp3 knockout mice demonstrated no survival advantage under mere heat exposure. In animals with prior infection, their heat tolerance was severely impaired and NLRP3 inflammasome induced neuroinflammation was detected. The use of Nlrp3 knockout mice enhanced heat tolerance and alleviated heat stroke-induced death by reducing mice hypothalamus IL-1β production with prior infection condition. Furthermore, IL-1β neutralizing antibody injection significantly extended endotoxemic mice survival under heat stroke. Conclusions Based on the above results, NLRP3/IL-1β induced neuroinflammation might be an important mechanistic factor in heat stroke pathology, especially with prior infection. IL-1β may serve as a biomarker for heat stroke severity and potential therapeutic method.
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Affiliation(s)
- Zi-Teng Zhang
- Department of Hepato-Biliary Surgery, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China
| | - Xiao-Lei Gu
- Department of Pharmacy, The Affiliated Tumor Hospital of Zhengzhou University, Zhengzhou, 450008, China
| | - Xin Zhao
- Department of Hepato-Biliary Surgery, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China
| | - Xian He
- School of Pharmacy, Dali University, Dali, 671000, China.,Fifth Medical Center of PLA General Hospital, Beijing, 100000, China
| | - Hao-Wei Shi
- Department of Neurosurgery, Hebei Provincial People's Hospital, Shijiazhuang, 050051, China
| | - Kun Zhang
- Department of Hepato-Biliary Surgery, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China
| | - Yi-Ming Zhang
- Department of Hepato-Biliary Surgery, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China
| | - Yi-Nan Su
- Department of Hepato-Biliary Surgery, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China
| | - Jiang-Bo Zhu
- Department of Health Toxicology, Faculty of Navy Medicine, Navy Medical University, Shanghai, 200433, China
| | - Zhi-Wei Li
- Department of Hepato-Biliary Surgery, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China.
| | - Guo-Bao Li
- Department of Lung Disease, Shenzhen Third People's Hospital, The Second Affiliated Hospital, Southern University of Science and Technology, No.29 Bulan Road, Longgang District, Shenzhen, 518055, China.
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26
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Buller MJ, Delves SK, Fogarty AL, Veenstra BJ. On the real-time prevention and monitoring of exertional heat illness in military personnel. J Sci Med Sport 2021; 24:975-981. [PMID: 34148796 DOI: 10.1016/j.jsams.2021.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/19/2021] [Accepted: 04/18/2021] [Indexed: 12/14/2022]
Abstract
The proliferation of user-friendly low-cost wearable sensors has brought the concept of real-time physiological monitoring for exertional heat illness to the cusp of reality. This paper reviews and discusses the current state of the art in real-time physiological status monitoring for exertional heat illness mitigation within the military context. The review examines how both advanced sensor systems, models and algorithms are being combined in an international and collaborative way and how this is providing real solutions to military units to reduce the risk held by the commander. This paper provides additional detail into the process of integrating physiological status monitoring into military training, it explores the development of on-body sensors, the algorithms that can provide actionable information, the process of planning and dynamic risk assessment and describes some of the physiological monitoring systems that are currently being developed by the representative nations. It then discusses the knowledge gaps of how the technology will be integrated into military training, the importance of meaningful, accurate information that is both sensitive and specific and further developing the accuracy of the algorithms and models that are being employed. Finally, it talks about future direction and how individualizing physiological status monitoring can lead to performance enhancement in the form of individualized heat acclimatization programs. In conclusion, physiological status monitoring is at a stage of transition and integration where it can be used effectively to manage and reduce exertional heat illness to enable military personnel to train hard-train safe.
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Affiliation(s)
- M J Buller
- U.S. Army Research Institute of Environmental Medicine, USA.
| | - S K Delves
- Institute of Naval Medicine, United Kingdom
| | - A L Fogarty
- Defence Science and Technology Group, Australia
| | - B J Veenstra
- Institute of Training Medicine and Training Physiology, TGTF, Royal Netherlands Army, the Netherlands
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27
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Périard JD, Eijsvogels TMH, Daanen HAM. Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies. Physiol Rev 2021; 101:1873-1979. [PMID: 33829868 DOI: 10.1152/physrev.00038.2020] [Citation(s) in RCA: 138] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.
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Affiliation(s)
- Julien D Périard
- University of Canberra Research Institute for Sport and Exercise, Bruce, Australia
| | - Thijs M H Eijsvogels
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hein A M Daanen
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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28
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Otani S, Funaki Ishizu S, Masumoto T, Amano H, Kurozawa Y. The Effect of Minimum and Maximum Air Temperatures in the Summer on Heat Stroke in Japan: A Time-Stratified Case-Crossover Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041632. [PMID: 33572074 PMCID: PMC7915318 DOI: 10.3390/ijerph18041632] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/23/2021] [Accepted: 02/05/2021] [Indexed: 12/17/2022]
Abstract
An increase in the global surface temperature and changes in urban morphologies are associated with increased heat stress especially in urban areas. This can be one of the contributing factors underlying an increase in heat strokes. We examined the impact of summer minimum air temperatures, which often represent nighttime temperatures, as well as a maximum temperature on a heat stroke. We collected data from the records of daily ambulance transports for heat strokes and meteorological data for July and August of 2017–2019 in the Tottori Prefecture, Japan. A time-stratified case-crossover design was used to determine the association of maximum/minimum air temperatures and the incidence of heat strokes. We used a logistic regression to identify factors associated with the severity of heat strokes. A total of 1108 cases were identified with 373 (33.7%) calls originating in the home (of these, 59.8% were the age of ≥ 75). A total of 65.8% of cases under the age of 18 were related to exercise. Days with a minimum temperature ≥ 25 °C had an odds ratio (95% confidence interval) of 3.77 (2.19, 6.51) for the incidence of an exercise-related heat stroke (reference: days with a minimum temperature < 23 °C). The odds ratio for a heat stroke occurring at home or for calls for an ambulance to the home was 6.75 (4.47, 10.20). The severity of the heat stroke was associated with older age but not with air temperature. Minimum and maximum air temperatures may be associated with the incidence of heat strokes and in particular the former with non-exertional heat strokes.
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Affiliation(s)
- Shinji Otani
- International Platform for Dryland Research and Education, Tottori University, Tottori 680-0001, Japan
- Correspondence: ; Tel.: +81-857-30-6317
| | - Satomi Funaki Ishizu
- Division of Health Administration and Promotion, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan; (S.F.I.); (T.M.); (H.A.); (Y.K.)
| | - Toshio Masumoto
- Division of Health Administration and Promotion, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan; (S.F.I.); (T.M.); (H.A.); (Y.K.)
| | - Hiroki Amano
- Division of Health Administration and Promotion, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan; (S.F.I.); (T.M.); (H.A.); (Y.K.)
| | - Youichi Kurozawa
- Division of Health Administration and Promotion, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan; (S.F.I.); (T.M.); (H.A.); (Y.K.)
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The Potential Role of Exercise-Induced Muscle Damage in Exertional Heat Stroke. Sports Med 2021; 51:863-872. [PMID: 33528800 DOI: 10.1007/s40279-021-01427-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2021] [Indexed: 01/06/2023]
Abstract
Exertional heat stroke (EHS) is a life-threatening condition that affects mainly athletes, military personnel, firefighters, and occupational workers. EHS is frequently observed in non-compensable conditions (where the body is unable to maintain a steady thermal balance) as a result of heavy heat stress and muscle contraction associated with prolonged and strenuous physical and occupational activities, resulting in central nervous system dysfunction followed by multi-organ damage and failure. Since the pathophysiology of EHS is complex and involves multiple organs and systems, any condition that changes the interrelated systems may increase the risk for EHS. It has been suggested that exercise-induced muscle damage (EIMD) can lead to thermoregulatory impairment and systemic inflammation, which could be a potential predisposing factor for EHS. In this review article, we aim to (1) address the evidence of EIMD as a predisposing factor for EHS and (2) propose a possible mechanism of how performing muscle-damaging exercise in the heat may aggravate muscle damage and subsequent risk of EHS and acute kidney injury (AKI). Such an understanding could be meaningful to minimize the risks of EHS and AKI for individuals with muscle damage due to engaging in physical work in hot environments.
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Tipton M. Experimental Physiology special issue: Extreme environmental physiology. Exp Physiol 2020; 106:1-3. [PMID: 33382514 DOI: 10.1113/ep089151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 10/08/2020] [Indexed: 11/08/2022]
Affiliation(s)
- Mike Tipton
- Extreme Environments Laboratory, School of Sport, Health & Exercise Science, University of Portsmouth, Portsmouth, UK
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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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Influence of aerobic fitness on gastrointestinal barrier integrity and microbial translocation following a fixed-intensity military exertional heat stress test. Eur J Appl Physiol 2020; 120:2325-2337. [PMID: 32794058 DOI: 10.1007/s00421-020-04455-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE Exertional-heat stress adversely disrupts gastrointestinal (GI) barrier integrity, whereby subsequent microbial translocation (MT) can result in potentially serious health consequences. To date, the influence of aerobic fitness on GI barrier integrity and MT following exertional-heat stress is poorly characterised. METHOD Ten untrained (UT; VO2max = 45 ± 3 ml·kg-1·min-1) and ten highly trained (HT; VO2max = 64 ± 4 ml·kg-1·min-1) males completed an ecologically valid (military) 80-min fixed-intensity exertional-heat stress test (EHST). Venous blood was drawn immediately pre- and post-EHST. GI barrier integrity was assessed using the serum dual-sugar absorption test (DSAT) and plasma Intestinal Fatty-Acid Binding Protein (I-FABP). MT was assessed using plasma Bacteroides/total 16S DNA. RESULTS UT experienced greater thermoregulatory, cardiovascular and perceptual strain (p < 0.05) than HT during the EHST. Serum DSAT responses were similar between the two groups (p = 0.59), although Δ I-FABP was greater (p = 0.04) in the UT (1.14 ± 1.36 ng·ml-1) versus HT (0.20 ± 0.29 ng·ml-1) group. Bacteroides/Total 16S DNA ratio was unchanged (Δ; -0.04 ± 0.18) following the EHST in the HT group, but increased (Δ; 0.19 ± 0.25) in the UT group (p = 0.05). Weekly aerobic training hours had a weak, negative correlation with Δ I-FABP and Bacteroides/total 16S DNA responses. CONCLUSION When exercising at the same absolute workload, UT individuals are more susceptible to small intestinal epithelial injury and MT than HT individuals. These responses appear partially attributable to greater thermoregulatory, cardiovascular, and perceptual strain.
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