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Wen J, Cheng J, Wang L, Li C, Zou Y, Wu J, Liu J. Dynamic molecular choreography induced by acute heat exposure in human males: a longitudinal multi-omics profiling study. Front Public Health 2024; 12:1384544. [PMID: 38813424 PMCID: PMC11135052 DOI: 10.3389/fpubh.2024.1384544] [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: 02/09/2024] [Accepted: 05/02/2024] [Indexed: 05/31/2024] Open
Abstract
Introduction Extreme heat events caused by occupational exposure and heat waves are becoming more common. However, the molecular changes underlying the response to heat exposure in humans remain to be elucidated. Methods This study used longitudinal multi-omics profiling to assess the impact of acute heat exposure (50°C for 30 min) in 24 subjects from a mine rescue team. Intravenous blood samples were collected before acute heat exposure (baseline) and at 5 min, 30 min, 1 h, and 24 h after acute heat exposure (recovery). In-depth multi-omics profiling was performed on each sample, including plasma proteomics (untargeted) and metabolomics (untargeted). Results After data curation and annotation, the final dataset contained 2,473 analytes, including 478 proteins and 1995 metabolites. Time-series analysis unveiled an orchestrated molecular choreography of changes involving the immune response, coagulation, acid-base balance, oxidative stress, cytoskeleton, and energy metabolism. Further analysis through protein-protein interactions and network analysis revealed potential regulators of acute heat exposure. Moreover, novel blood-based analytes that predicted change in cardiopulmonary function after acute heat exposure were identified. Conclusion This study provided a comprehensive investigation of the dynamic molecular changes that underlie the complex physiological processes that occur in human males who undergo heat exposure. Our findings will help health impact assessment of extreme high temperature and inspire future mechanistic and clinical studies.
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Affiliation(s)
- Jirui Wen
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
- State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, Sichuan University, Chengdu, China
| | - Juan Cheng
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
| | - Ling Wang
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
| | - Can Li
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
| | - Yuhao Zou
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
| | - Jiang Wu
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
- Med-X Center for Manufacturing, Sichuan University, Chengdu, China
| | - Jifeng Liu
- Department of Otolaryngology-Head and Neck Surgery, Deep Underground Space Medical Center, West China Hospital, Sichuan University, Guoxuexiang, Chengdu, China
- Jinping Deep Underground Frontier Science and Dark Matter Key Laboratory of Sichuan Province, Liangshan, China
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Tramel W, Schram B, Canetti E, Orr R. An Examination of Subjective and Objective Measures of Stress in Tactical Populations: A Scoping Review. Healthcare (Basel) 2023; 11:2515. [PMID: 37761712 PMCID: PMC10530665 DOI: 10.3390/healthcare11182515] [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: 08/02/2023] [Revised: 09/06/2023] [Accepted: 09/09/2023] [Indexed: 09/29/2023] Open
Abstract
Persons working in tactical occupations are often exposed to high-stress situations. If this stress is to be measured, an understanding of the stress outcomes used in these occupations is needed. The aim of this review was to capture and critically appraise research investigating subjective and objective outcome measures of physiological stress in tactical occupations. Several literature databases (PubMed, EMBASE, EBsco) were searched using key search words and terms. Studies meeting inclusion criteria were critically evaluated and scored by two authors using the Joanne Briggs Institute (JBI) critical appraisal tool. Of 17,171 articles, 42 studies were retained. The Cohen's Kappa agreement between authors was 0.829 with a mean JBI Score of included studies of 8.1/9 ± 0.37 points. Multiple subjective and objective measures were assessed during a variety of high-stress tasks and environments across different occupations, including police officers, emergency service personnel, firefighters, and soldiers in the military. Common objective outcomes measures were heart rate, cortisol, and body temperature, and subjective measures were ratings of perceived exertion, and the Self Trait Anxiety Inventory. Often used in combination (i.e., subjective and objective), these outcome measures can be used to monitor stressors faced by tactical personnel undergoing on-the-job training.
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Affiliation(s)
- Whitney Tramel
- Faculty of Health Sciences and Medicine, Bond University, Robina, QLD 4226, Australia; (B.S.); (E.C.); (R.O.)
| | - Ben Schram
- Faculty of Health Sciences and Medicine, Bond University, Robina, QLD 4226, Australia; (B.S.); (E.C.); (R.O.)
- Tactical Research Unit, Bond University, Robina, QLD 4226, Australia
| | - Elisa Canetti
- Faculty of Health Sciences and Medicine, Bond University, Robina, QLD 4226, Australia; (B.S.); (E.C.); (R.O.)
- Tactical Research Unit, Bond University, Robina, QLD 4226, Australia
| | - Robin Orr
- Faculty of Health Sciences and Medicine, Bond University, Robina, QLD 4226, Australia; (B.S.); (E.C.); (R.O.)
- Tactical Research Unit, Bond University, Robina, QLD 4226, Australia
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Morrissey MC, Langan SP, Brewer GJ, Struder JF, Navarro JS, Nye MN, Casa DJ. Limitations associated with thermoregulation and cardiovascular research assessing laborers performing work in the heat. Am J Ind Med 2023; 66:267-280. [PMID: 36748881 DOI: 10.1002/ajim.23462] [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: 07/19/2022] [Revised: 12/13/2022] [Accepted: 01/10/2023] [Indexed: 02/08/2023]
Abstract
PURPOSE To quantify the current literature and limitations associated with research examining thermoregulatory and cardiovascular strain in laborers working in the heat. METHODS PubMed, SCOPUS, and SPORTDiscus were searched for terms related to the cardiovascular system, heat stress, and physical work. Qualifying studies included adult participants (18-65 years old), a labor-intensive environment or exercise protocol simulating a labor environment, a minimum duration of 120 min of physical work, and environmental heat stress (ambient temperature ≥26.0°C and ≥30% relative humidity). Studies included at least one of the following outcomes: pre- and peak physical work, core temperature, heart rate (HR), systolic blood pressure, diastolic blood pressure, HR variability, and rate pressure product. RESULTS Twenty-one out of 1559 potential studies qualified from our search. There was a total of 598 participants (mean = 28 ± 50 participants per study, range = 4-238 participants per study), which included 51 females (8.5%) and 547 males (91.5%). Of the participants, 3.8% had cardiovascular risk factors (diabetes: n = 10; hypertension: n = 13) and 96.2% were characterized as "healthy". Fifty-seven percent of the included studies were performed in a laboratory setting. CONCLUSIONS Studies were predominantly in men (91.5%), laboratory settings (57%), and "healthy" individuals (96.2%). To advance equity in protection against occupational heat stress and better inform future heat safety recommendations to protect all workers, future studies must focus on addressing these limitations. Employers, supervisors, and other safety stakeholders should consider these limitations while implementing current heat safety recommendations.
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Affiliation(s)
| | - Sean P Langan
- Korey Stringer Institute, University of Connecticut, Storrs, Connecticut, USA
| | - Gabrielle J Brewer
- Korey Stringer Institute, University of Connecticut, Storrs, Connecticut, USA
| | - Jeb F Struder
- Korey Stringer Institute, University of Connecticut, Storrs, Connecticut, USA
| | - John S Navarro
- Korey Stringer Institute, University of Connecticut, Storrs, Connecticut, USA
| | - Megan N Nye
- Korey Stringer Institute, University of Connecticut, Storrs, Connecticut, USA
| | - Douglas J Casa
- Korey Stringer Institute, University of Connecticut, Storrs, Connecticut, USA
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Yang J, Zhang Y, Huang Y, Chen W. Effects of liquid cooling garment on physiological and psychological strain of firefighter in hot and warm environments. J Therm Biol 2023; 112:103487. [PMID: 36796928 DOI: 10.1016/j.jtherbio.2023.103487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/19/2023] [Accepted: 01/19/2023] [Indexed: 02/04/2023]
Abstract
This study aimed to explore the effects of a liquid cooling garment on the physiological and psychological strains of firefighters. Twelve participants wearing firefighting protective equipment with the liquid cooling garment (LCG group) and without the liquid cooling garment (CON group) were recruited to conduct human trials in a climate chamber. During the trials, physiological parameters (mean skin temperature (Tsk), core temperature (Tc), and heart rate (HR)) and psychological parameters (thermal sensation vote (TSV), thermal comfort vote (TCV), and rating of perceived exertion (RPE)) were measured continuously. The heat storage, sweating loss, physiological strain index (PSI), and perceptual strain index (PeSI) were calculated. The results indicated that the liquid cooling garment decreased the mean skin temperature (maximum value of 0.62 °C), scapula skin temperature (maximum value of 1.90 °C), sweating loss (26%), and PSI (0.95 scales) with a significant difference (p < 0.05) at some time points when compared with the CON group. Moreover, the liquid cooling garment had little influence (p > 0.05) on core temperature, heart rate, TSV, TCV, RPE, and PeSI. The association analysis indicated that psychological strain had the potential to predict physiological heat strain with an R2 value of 0.86 between the PeSI and PSI. This study offers insights into the evaluation of cooling system performance, the design of next-generation cooling systems, and the improvement of firefighters' benefits.
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Affiliation(s)
- Jie Yang
- College of Safety Science and Engineering, Xi'an University of Science and Technology, Xi'an, 710054, China
| | - Yiwen Zhang
- College of Safety Science and Engineering, Xi'an University of Science and Technology, Xi'an, 710054, China
| | - Yiming Huang
- School of Energy and Building Environment, Guilin University of Aerospace Technology, Guilin, 541004, China
| | - Weiwang Chen
- Key Laboratory of Civil Aviation Thermal Hazards Prevention and Emergency Response, Civil Aviation University of China, Tianjin, 300300, China.
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D King G, Pan E, Millin MG. Wilderness First Responder Medical Clearance - A Scoping Review with Recommendations. PREHOSP EMERG CARE 2023; 28:50-75. [PMID: 36595615 DOI: 10.1080/10903127.2022.2162650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/13/2022] [Indexed: 01/05/2023]
Abstract
BACKGROUND AND PURPOSE Due to environmental extremes, as well as the nature of the work itself, wilderness first responders are at risk of incurring medical events in the line of duty. There currently do not exist standardized and scientifically supported methods to screen for a wilderness first responder's risk of incurring a medical event. METHODS We performed multiple scoping reviews using PubMed and CINAHL. The reviews covered six medical screening criteria based on previous recommendations from the National Fire Protection Association (NFPA) and the US Forest Service, and we grouped our reviews into two categories: articles that addressed objective screening criteria, and articles that addressed subjective findings with the first responder. RESULTS Of the objective criteria, our reviews identified 21 articles addressing the ability to screen for risk of incurring a medical event by evaluation of a first responder's heart rate, 12 by blood pressure assessment, and 56 by assessment of body temperature. Of the subjective criteria we identified 19 articles focused on self-assessment, 34 articles on the use of standardized tools to assess for fatigue and sleepiness, and two articles on assessment of a first responder's urine to determine level of dehydration. We also identified seven additional articles through a hand search. Overall, there were 151 articles identified in our scoping reviews. These articles were largely of low quality, consisting mostly of case series without comparison groups. CONCLUSION There is a dearth of high-quality research into the medical assessment of first responders. We recommend that this paper, and measures discussed within it, be used as a starting point in the development of an evidence-based assessment protocol for wilderness first responders. We also recommend the development of a national database of medical events incurred by wilderness first responders to facilitate higher-quality research of screening protocols in this community.
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Affiliation(s)
- Gregory D King
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Maryland and Mid-Atlantic Wilderness Rescue Squad, Inc./Austere Medical Professionals, Dayton, Maryland, USA
| | - Erik Pan
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Maryland and Mid-Atlantic Wilderness Rescue Squad, Inc./Austere Medical Professionals, Dayton, Maryland, USA
| | - Michael G Millin
- Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Maryland and Mid-Atlantic Wilderness Rescue Squad, Inc./Austere Medical Professionals, Dayton, Maryland, USA
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Ioannou LG, Foster J, Morris NB, Piil JF, Havenith G, Mekjavic IB, Kenny GP, Nybo L, Flouris AD. Occupational heat strain in outdoor workers: A comprehensive review and meta-analysis. Temperature (Austin) 2022; 9:67-102. [PMID: 35655665 PMCID: PMC9154804 DOI: 10.1080/23328940.2022.2030634] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 12/29/2022] Open
Abstract
The present comprehensive review (i) summarizes the current knowledge on the impacts of occupational heat stress on outdoor workers, (ii) provides a historical background on this issue, (iii) presents a meta-analysis of published data, (iv) explores inter-individual and intra-individual factors, (v) discusses the available heat mitigation strategies, (vi) estimates physical work capacity, labour productivity, and metabolic rate for the year 2030, and (vii) provides an overview of existing policy and legal frameworks on occupational heat exposure. Meta-analytic findings from 38 field studies that involved monitoring 2,409 outdoor workers across 41 jobs in 21 countries suggest that occupational heat stress increases the core (r = 0.44) and skin (r = 0.44) temperatures, as well as the heart rate (r = 0.38) and urine specific gravity (r = 0.13) of outdoor workers (all p < 0.05). Moreover, it diminishes the capacity of outdoor workers for manual labour (r = -0.82; p < 0.001) and is responsible for more than two thirds of the reduction in their metabolic rate. Importantly, our analysis shows that physical work capacity is projected to be highly affected by the ongoing anthropogenic global warming. Nevertheless, the metabolic rate and, therefore, labour productivity are projected to remain at levels higher than the workers' physical work capacity, indicating that people will continue to work more intensely than they should to meet their financial obligations for food and shelter. In this respect, complementary measures targeting self-pacing, hydration, work-rest regimes, ventilated garments, and mechanization can be adopted to protect outdoor workers.
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Affiliation(s)
- Leonidas G. Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Josh Foster
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Nathan B. Morris
- Department of Human Physiology & Nutrition, University of Colorado, Springs, Colorado, USA
| | - Jacob F. Piil
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - George Havenith
- Environmental Ergonomics Research Centre, Loughborough Design School, Loughborough University, Loughborough, UK
| | - Igor B. Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, Copenhagen, Denmark
| | - Andreas D. Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
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Fullagar H, Notley SR, Fransen J, Richardson A, Stadnyk A, Lu D, Brown G, Duffield R. Cooling strategies for firefighters: Effects on physiological, physical, and visuo-motor outcomes following fire-fighting tasks in the heat. J Therm Biol 2022; 106:103236. [DOI: 10.1016/j.jtherbio.2022.103236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 02/21/2022] [Accepted: 03/26/2022] [Indexed: 11/25/2022]
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Rosales AM, Dodds PS, Hailes WS, Sol JA, Coker RH, Quindry JC, Ruby BC. Deterioration of Lipid Metabolism Despite Fitness Improvements in Wildland Firefighters. J Occup Environ Med 2021; 64:385-389. [PMID: 34817456 DOI: 10.1097/jom.0000000000002446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Determine serum lipid and general health/fitness alterations following a 5-month wildfire suppression season. METHODS We recruited 100 wildland firefighters (WLFFs) to a 5-month pre- to post-season observational study. Nude body mass, blood pressure (BP), grip strength, and step-test heart rate (HR) were recorded. Blood samples were collected for lipid panel analysis (total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol, triglycerides, triglyceride:HDL-cholesterol ratio). Two-tailed dependent t-tests determined statistical significance (p < 0.05). RESULTS There were pre- to post-season changes in nude body mass (+2 ± 4%, p = 0.001), systolic BP (-2 ± 10%, p = 0.01), step-test HR (-5 ± 10%, p < 0.001), and all serum lipids (total cholesterol: +5 ± 14%, p = 0.02, HDL-cholesterol: -1 ± 17%, p = 0.04, LDL-cholesterol: +8 ± 22%, p = 0.02, VLDL-cholesterol: +31 ± 49%, p < 0.001, triglycerides: +30 ± 49%, p < 0.001, triglyceride:HDL-cholesterol ratio: +37 ± 58%, p < 0.001). Pre- to post-season diastolic BP (p = 0.12) and grip strength (p = 0.60) remained stable. CONCLUSIONS WLFFs demonstrate maladaptive serum lipids and body mass alterations despite subtle aerobic fitness improvements.
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Affiliation(s)
- Alejandro M Rosales
- Montana Center for Work Physiology and Exercise Metabolism, The University of Montana, Missoula, MT (Rosales, Dodds, Hailes, Ruby), Cardio Protection Laboratory, The University of Montana, Missoula, MT (Quindry), Integrative Physiology Laboratory, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK (Coker), National Technology and Development Program, United States Department of Agriculture Forest Service, Missoula, MT (Sol)
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Fundamental Concepts of Human Thermoregulation and Adaptation to Heat: A Review in the Context of Global Warming. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17217795. [PMID: 33114437 PMCID: PMC7662600 DOI: 10.3390/ijerph17217795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022]
Abstract
The international community has recognized global warming as an impending catastrophe that poses significant threat to life on earth. In response, the signatories of the Paris Agreement (2015) have committed to limit the increase in global mean temperature to <1.5 °C from pre-industry period, which is defined as 1850–1890. Considering that the protection of human life is a central focus in the Paris Agreement, the naturally endowed properties of the human body to protect itself from environmental extremes should form the core of an integrated and multifaceted solution against global warming. Scholars believe that heat and thermoregulation played important roles in the evolution of life and continue to be a central mechanism that allows humans to explore, labor and live in extreme conditions. However, the international effort against global warming has focused primarily on protecting the environment and on the reduction of greenhouse gases by changing human behavior, industrial practices and government policies, with limited consideration given to the nature and design of the human thermoregulatory system. Global warming is projected to challenge the limits of human thermoregulation, which can be enhanced by complementing innate human thermo-plasticity with the appropriate behavioral changes and technological innovations. Therefore, the primary aim of this review is to discuss the fundamental concepts and physiology of human thermoregulation as the underlying bases for human adaptation to global warming. Potential strategies to extend human tolerance against environmental heat through behavioral adaptations and technological innovations will also be discussed. An important behavioral adaptation postulated by this review is that sleep/wake cycles would gravitate towards a sub-nocturnal pattern, especially for outdoor activities, to avoid the heat in the day. Technologically, the current concept of air conditioning the space in the room would likely steer towards the concept of targeted body surface cooling. The current review was conducted using materials that were derived from PubMed search engine and the personal library of the author. The PubMed search was conducted using combinations of keywords that are related to the theme and topics in the respective sections of the review. The final set of articles selected were considered “state of the art,” based on their contributions to the strength of scientific evidence and novelty in the domain knowledge on human thermoregulation and global warming.
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Noonan CW, Semmens EO. Heat-related illness among wildland firefighters. Occup Environ Med 2020; 77:431-432. [PMID: 32295820 PMCID: PMC7679056 DOI: 10.1136/oemed-2019-106391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/11/2020] [Accepted: 04/05/2020] [Indexed: 11/04/2022]
Affiliation(s)
- Curtis W Noonan
- Center for Population Health Research, University of Montana, Missoula, Montana, USA
- School of Public and Community Health Sciences, University of Montana, Missoula, Montana, USA
| | - Erin O'Brien Semmens
- Center for Population Health Research, University of Montana, Missoula, Montana, USA
- School of Public and Community Health Sciences, University of Montana, Missoula, Montana, USA
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Hot, Tired and Hungry: The Snacking Behaviour and Food Cravings of Firefighters During Multi-Day Simulated Wildfire Suppression. Nutrients 2020; 12:nu12041160. [PMID: 32326354 PMCID: PMC7230571 DOI: 10.3390/nu12041160] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/18/2020] [Accepted: 04/19/2020] [Indexed: 11/30/2022] Open
Abstract
Firefighters are exposed to numerous stressors during wildfire suppression, including working in hot temperatures and sleep restricted conditions. Research has shown that when sleep restricted, individuals choose foods higher in carbohydrates, fat, and sugar, and have increased cravings for calorie dense foods. However, there is currently no research on the combined effect of heat and sleep restriction on snacking behaviour. Conducting secondary analyses from a larger study, the current study aimed to investigate the impact of heat and sleep restriction on snacking behaviour and food cravings. Sixty-six firefighters completed three days of simulated physically demanding firefighting work and were randomly allocated to either the control (n = 18, CON; 19 °C, 8 h sleep opportunity), sleep restricted (n = 16, SR; 19 °C, 4-h sleep opportunity), hot (n = 18, HOT; 33 °C, 8 h sleep opportunity), or hot and sleep restricted (n = 14 HOT + SR; 33 °C, 4-h sleep opportunity) condition. During rest periods firefighters were able to self-select sweet, savoury, or healthy snacks from a ration pack and were asked to rate their hunger, fullness, and cravings every two hours (eating block). Mixed model analyses revealed no difference in total energy intake between conditions, however there was a significant interaction between eating block and condition, with those in the CON, HOT, and HOT + SR condition consuming significantly more energy between 1230 and 1430 compared to the SR condition (p = 0.002). Sleep restriction and heat did not impact feelings of hunger and fullness across the day, and did not lead to greater cravings for snacks, with no differences between conditions. These findings suggest that under various simulated firefighting conditions, it is not the amount of food that differs but the timing of food intake, with those that are required to work in hot conditions while sleep restricted more likely to consume food between 1230 and 1430. This has potential implications for the time of day in which a greater amount of food should be available for firefighters.
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12
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West MR, Costello S, Sol JA, Domitrovich JW. Risk for heat-related illness among wildland firefighters: job tasks and core body temperature change. Occup Environ Med 2020; 77:433-438. [DOI: 10.1136/oemed-2019-106186] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/09/2019] [Accepted: 12/14/2019] [Indexed: 11/04/2022]
Abstract
ObjectivesIn order to make recommendations to protect wildland firefighters (WLFFs) from heat-related illness, the role physical exertion plays on core body temperature (Tc) in the work environment needs to be considered. We aimed to estimate the association of time-varying job tasks with differing exertion levels on change in Tc, among WLFFs engaged in fire management activities, while controlling for ambient conditions and individual characteristics. In addition, we examined whether duration of tasks modified the relationship between task and change in Tc.MethodsWe used data from The Wildland Firefighter Heat Related Illness study, a repeated measures study with individual-level data on 301 WLFFs from 2013 to 2016. Job tasks over one full shift were recorded and categorised into four levels (sedentary, light, moderate and high) based on estimated exertion levels. Tc was measured every 15 s using an ingestible sensor and personal monitors measured ambient conditions. The analysis used generalised estimating equations with an autoregressive correlation structure.ResultsWe found statistically significant associations between job tasks with increased physical demand and increases in Tc. When compared with sedentary tasks, the estimated increases in Tc for light, moderate and high activity tasks of average duration were 0.07°C (95% CI 0.02 to 0.11°C), 0.19°C (95% CI 0.15 to 0.23) and 0.44°C (95% CI 0.39 to 0.49°C), respectively. In addition, we found evidence of interaction between task type and duration.ConclusionsThis study supports the hypothesis that occupational exposure to physical exertion increases Tc, highlighting the need to update recommendations to protect WLFFs from heat-related illness.
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13
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Cvirn MA, Dorrian J, Smith BP, Vincent GE, Jay SM, Roach GD, Sargent C, Larsen B, Aisbett B, Ferguson SA. The effects of hydration on cognitive performance during a simulated wildfire suppression shift in temperate and hot conditions. APPLIED ERGONOMICS 2019; 77:9-15. [PMID: 30832782 DOI: 10.1016/j.apergo.2018.12.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 10/21/2018] [Accepted: 12/28/2018] [Indexed: 06/09/2023]
Abstract
The effects on dehydration and cognitive performance from heat and/or physical activity are well established in the laboratory, although have not yet been studied for personnel working in occupations such as wildland firefighting regularly exposed to these types of conditions. This study aimed to investigate the effects of temperature and dehydration on seventy-three volunteer firefighters (35.7 ± 13.7 years, mean ± standard deviation) during a simulation of wildfire suppression under either control or hot (18-20; or 33-35 °C) temperature conditions. Results showed cognitive performance on the psychomotor vigilance task declined when participants were dehydrated in the heat and Stroop task performance was impaired when dehydrated late in the afternoon. Firefighters may be at risk of deteriorations in simple cognitive functions in the heat whilst dehydrated, although may also experience impairments in complex cognitive functions if dehydrated late in the day, irrespective of the environmental temperature.
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Affiliation(s)
- Michael A Cvirn
- Appleton Institute, Central Queensland University, Adelaide, Australia.
| | - Jillian Dorrian
- Centre for Sleep Research, University of South Australia, Adelaide, Australia
| | - Bradley P Smith
- Appleton Institute, Central Queensland University, Adelaide, Australia
| | - Grace E Vincent
- Appleton Institute, Central Queensland University, Adelaide, Australia
| | - Sarah M Jay
- Appleton Institute, Central Queensland University, Adelaide, Australia
| | - Greg D Roach
- Appleton Institute, Central Queensland University, Adelaide, Australia
| | - Charli Sargent
- Appleton Institute, Central Queensland University, Adelaide, Australia
| | - Brianna Larsen
- Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, Victoria, Australia
| | - Brad Aisbett
- Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, Victoria, Australia
| | - Sally A Ferguson
- Appleton Institute, Central Queensland University, Adelaide, Australia
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14
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Abrard S, Bertrand M, De Valence T, Schaupp T. Physiological, cognitive and neuromuscular effects of heat exposure on firefighters after a live training scenario. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2018; 27:185-193. [PMID: 30507358 DOI: 10.1080/10803548.2018.1550899] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
This study investigated physiological, cognitive and neuromuscular performances in firefighters after a structural live-fire scenario. Changes in vital signs, environmental parameters and cognitive and neuromuscular performance were measured before and after a live-fire training session in a closed environment, in conditions similar to those one could encounter in a structural fire. Very high ambient temperature peaks were reached during the 30-min sessions. After the session, the forehead temperature was increased by 0.5 °C, mean water body loss was 639 ml and the mean heart rate increase was 7.5 bpm. Mental calculation speed did not vary significantly, however we observed a reduction in reaction time. These findings demonstrated that after 30 min of exposure, heat stress had little impact on firemen. Stress activation seems beneficial after firefighting operations. Normal vital parameters should allow re-engagement for a second firefighting task. This result must be compared with longer exposures.
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Affiliation(s)
- Stanislas Abrard
- Departmental Fire and Rescue Services of Maine-et-Loire (SDIS 49), Health and Medical Rescue Service (SSSM), France.,Anesthesiology and Intensive Care Department, Angers University Hospital, France
| | - Mathieu Bertrand
- Departmental Fire and Rescue Services of Maine-et-Loire (SDIS 49), Prospective Service and Training Engineering, France
| | | | - Thierry Schaupp
- Departmental Fire and Rescue Services of Maine-et-Loire (SDIS 49), Health and Medical Rescue Service (SSSM), France
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15
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Zare S, Hemmatjo R, Allahyari T, Hajaghazadeh M, Hajivandi A, Aghabeigi M, Kazemi R. Comparison of the effect of typical firefighting activities, live fire drills and rescue operations at height on firefighters' physiological responses and cognitive function. ERGONOMICS 2018; 61:1334-1344. [PMID: 29862929 DOI: 10.1080/00140139.2018.1484524] [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: 08/22/2017] [Revised: 04/11/2018] [Accepted: 05/02/2018] [Indexed: 06/08/2023]
Abstract
This study examined the impact of various types of firefighting activities on firefighters' physiological responses and cognitive function. Each firefighter was engaged in three conditions: (1) Live-fire activities (LFA), (2) Typical firefighting activities (TFA), and (3) Rescue operations at height (ROH). The effects of various types of firefighting activities on the physiological responses and cognitive function were evaluated by heart rate (HR), temporal artery temperature (TT), and the correct response (CR) on a cognitive test. The results indicated that, compared to the baseline, physiological response increased, while information processing performance decreased after the activity. Furthermore, HR and TT were significantly lower at the end of the firefighting activity in the LFA (149.33 bpm; 38.08 °C) compared with the TFA (152.22 bpm; 38.17 °C) and ROH (159.28 bpm; 38.24 °C) conditions. Also, CR was significantly higher at the end of the activity in the LFA and TFA compared with the ROH condition. The results showed that rescue at height was more intensive than the other firefighting tasks in decreasing physiological and cognitive function capacity after the experiment. Practitioner Summary: We assumed that various types of firefighting activities would have different effects on physiological and cognitive functions during firefighting activities. The Findings suggest that rescue at height operations, performed without the use of special protective equipment, was more influential than other firefighting duties in changing firefighters' physiological and cognitive capacity. Abbreviations: CR: correct response; LFA: live-fire activities; TFA: typical firefighting activities; ROH: rescue operations at height; HR: heart rate; TT: temporal artery tempearture; PASAT: pased auditory serila addition teat; FPC: firefighting protective clothing.
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Affiliation(s)
- Sajad Zare
- a Department of Occupational Health, School of Public Health , Kerman University of Medical Sciences , Kerman , Iran
| | - Rasoul Hemmatjo
- b Department of Occupational Health Engineering, School of Health , Urmia University of Medical Sciences , Urmia , Iran
| | - Teimour Allahyari
- c Department of Occupational Health, School of Health , Urmia University of Medical Sciences , Urmia , Iran
| | - Mohammad Hajaghazadeh
- d Department of Occupational Health Engineering, School of Public Health , Urmia University of Medical Sciences , Urmia , Iran
| | - Abdollah Hajivandi
- e Department of Biostatistics, School of Public Health , Bushehr University of Medical Sciences , Bushehr , Iran
| | - Mandana Aghabeigi
- f Department National Petrochemical Company of Tehran , Tehran , Iran
| | - Reza Kazemi
- g Department of Ergonomics, School of Public Health , Shiraz University of Medical Sciences , Iran
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16
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Yasuda N, Ruby BC. Assessment of urinary protein composition in response to consecutive days of wildland firefighting. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2018; 25:27-34. [PMID: 29157150 DOI: 10.1080/10803548.2017.1407524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to examine the pattern of urinary protein excretion induced by 3 consecutive days of wildland firefighting. Eighteen male active-duty military personnel served as the participants. All testing on the 3 consecutive days was conducted at a Northwestern USA fire camp. All participants consumed military-based foods containing 2620-2864 kcal/day. The work activity was evaluated with an accelerometer in association with body weight and hydration markers over the experimental period. Urinary samples were collected pre and post workshift on days 1 and 3 to assess glomerular and tubular protein excretion (total protein, albumin, β2-microglobulin, N-acetyl-β-d-glucosaminidase and creatinine). The urinary levels of glomerular and tubular protein were not significantly different. The main findings of the present study indicate that similar alterations of urinary protein composition can be observed over consecutive days of wildland firefighting, which appears to be dependent on intensity rather than total work output.
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Affiliation(s)
- Nobuo Yasuda
- a Montana Center for Work Physiology and Exercise Metabolism , The University of Montana , USA
| | - Brent C Ruby
- a Montana Center for Work Physiology and Exercise Metabolism , The University of Montana , USA
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17
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Hemmatjo R, Motamedzade M, Aliabadi M, Kalatpour O, Farhadian M. The Effect of Various Hot Environments on Physiological Responses and Information Processing Performance Following Firefighting Activities in a Smoke-Diving Room. Saf Health Work 2017; 8:386-392. [PMID: 29276638 PMCID: PMC5715452 DOI: 10.1016/j.shaw.2017.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 02/15/2017] [Indexed: 11/30/2022] Open
Abstract
Background Fire service workers often implement multiple duties in the emergency conditions, with such duties being mostly conducted in various ambient temperatures. Methods The aim of the current study was to assess the firefighters' physiological responses, information processing, and working memory prior to and following simulated firefighting activities in three different hot environments. Seventeen healthy male firefighters performed simulated firefighting tasks in three separate conditions, namely (1) low heat (LH; 29–31°C, 55–60% relative humidity), (2) moderate heat (MH; 32–34°C, 55–60% relative humidity), and (3) severe heat (SH; 35–37°C, 55–60% relative humidity). It took about 45–50 minutes for each firefighter to finish all defined firefighting activities and the paced auditory serial addition test (PASAT). Results At the end of all the three experimental conditions, heart rate (HR) and tympanic temperature (TT) increased, while PASAT scores as a measure of information processing performance decreased relative to baseline. HR and TT were significantly higher at the end of the experiment in the SH (159.41 ± 4.25 beats/min; 38.22 ± 0.10°C) compared with the MH (156.59 ± 3.77 beats/min; 38.20 ± 0.10°C) and LH (154.24 ± 4.67 beats/min; 38.17 ± 0.10°C) conditions (p < 0.05). There was no significant difference in PASAT scores between LH and MH (p > 0.05). Nonetheless, there was a measurable difference in PASAT scores between LH and SH (p < 0.05). Conclusion These consequences demonstrate that ambient temperature is effective in raising the physiological responses following firefighting activities. It is therefore argued that further increase of ambient temperature can impact firefighters' information processing and working memory during firefighting activity.
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Affiliation(s)
- Rasoul Hemmatjo
- Department of Occupational Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Majid Motamedzade
- Department of Ergonomics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
- Corresponding author. Department of Ergonomics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.Department of ErgonomicsSchool of Public HealthHamadan University of Medical SciencesHamadanIran
| | - Mohsen Aliabadi
- Department of Occupational Health, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Omid Kalatpour
- Department of Occupational Health, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Farhadian
- Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
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18
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Hemmatjo R, Motamedzade M, Aliabadi M, Kalatpour O, Farhadian M. The effect of artificial smoke compound on physiological responses, cognitive functions and work performance during firefighting activities in a smoke-diving room: an intervention study. INTERNATIONAL JOURNAL OF OCCUPATIONAL SAFETY AND ERGONOMICS 2017; 24:358-365. [PMID: 28278005 DOI: 10.1080/10803548.2017.1299995] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This study investigated the combined effect of firefighting operations and exposure to smoke on physiological responses, cognitive functions and physical performance among firefighters. Each firefighter was engaged in two experimental conditions: (a) without artificial smoke, control (NS); (b) with artificial smoke (WS). The results of data analysis revealed that heart rate and body temperature increased significantly after the firefighting activities in the two conditions relative to baseline. In addition, reaction time (RT) and correct response (CR) decreased after the activity relative to baseline and there was a significant difference in RT and CR between the NS and WS conditions. There was also a significant difference in performance time between the NS and WS conditions. These findings demonstrated that a smoke compound has an insignificant effect on physiological responses during firefighting activity. On the contrary, the smoke compound has a detrimental influence on cognitive and physical performance.
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Affiliation(s)
- Rasoul Hemmatjo
- a Department of Occupational Health , Hamadan University of Medical Sciences , Iran
| | - Majid Motamedzade
- b Ergonomics Department , Hamadan University of Medical Sciences , Iran
| | - Mohsen Aliabadi
- c Department of Occupational Health , Hamadan University of Medical Science , Iran
| | - Omid Kalatpour
- c Department of Occupational Health , Hamadan University of Medical Science , Iran
| | - Maryam Farhadian
- d Department of Biostatistics , Hamadan University of Medical Science , Iran
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Hemmatjo R, Motamedzade M, Aliabadi M, Kalatpour O, Farhadian M. The effect of practical cooling strategies on physiological response and cognitive function during simulated firefighting tasks. Health Promot Perspect 2017; 7:66-73. [PMID: 28326286 PMCID: PMC5350552 DOI: 10.15171/hpp.2017.13] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 01/19/2017] [Indexed: 11/09/2022] Open
Abstract
Background: Firefighters often perform multiple tasks during firefighting operations under unknown and unpredictable conditions in hot and hostile environments. Methods: In this interventional study each firefighters engaged in 4 conditions: namely (1) no cooling device; control (NC), (2) cooling gel (CG), (3) cool vest (CV), and (4) CG+CV. Cooling effects of the employed interventions were evaluated based on heart rate (HR), temporal temperature (TT), reaction time (RT), and the correct response (CR). Results: HR and TT values for use of CG+CV (147.47 bpm [SD 4.8]; 37.88°C [SD 0.20]) and CV bpm (147.53 [SD 4.67]; 37.90°C [SD 0.22]) were significantly lower than the CG (153.67 bpm [SD 4.82]; 38.10°C [SD 0.22]) and NC (154.4 bpm [SD 4.91]; 38.11°C [SD 0.23]) at the end of the activity. RT and CR for use of CG + CV (389.87 ms [SD 6.12]; 143.53 [SD 1.24]) and CV (389.53 ms [SD 6.24]; 143.47 [SD 1.18]) were significantly higher than the CG (385.73 [SD 7.25] ms; 143.07 [SD 0.88]) and NC (385.67 ms [SD 7.19]; 143.00 [SD 0.84]) at the end of the activity. Conclusion: It is concluded that CV was more effective than the CG in attenuating physiological responses and cognitive functions during firefighting operations. Furthermore, combining CV with CG provides no additional benefit.
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Affiliation(s)
- Rasoul Hemmatjo
- Department of Occupational Health, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Majid Motamedzade
- Department of Ergonomics, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Mohsen Aliabadi
- Department of Occupational Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Omid Kalatpour
- Department of Occupational Health, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Maryam Farhadian
- Department of Biostatistics, Hamadan University of Medical Sciences, Hamadan, Iran
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The Impact of Heat Exposure and Sleep Restriction on Firefighters' Work Performance and Physiology during Simulated Wildfire Suppression. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14020180. [PMID: 28208688 PMCID: PMC5334734 DOI: 10.3390/ijerph14020180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/05/2017] [Accepted: 02/06/2017] [Indexed: 11/16/2022]
Abstract
This study was designed to examine the effects of ambient heat on firefighters' physical task performance, and physiological and perceptual responses when sleep restricted during simulated wildfire conditions. Thirty firefighters were randomly allocated to the sleep restricted (n = 17, SR; 19 °C, 4-h sleep opportunity) or hot and sleep restricted (n = 13, HOT + SR; 33 °C, 4-h sleep opportunity) condition. Firefighters performed two days of simulated, intermittent, self-paced work circuits comprising six firefighting tasks. Heart rate, and core temperature were measured continuously. After each task, firefighters reported their rating of perceived exertion and thermal sensation. Effort sensation was also reported after each work circuit. Fluids were consumed ad libitum. Urine volume and urine specific gravity were analysed. Sleep was monitored using polysomnography. There were no differences between the SR and HOT + SR groups in firefighters' physiological responses, hydration status, ratings of perceived exertion, motivation, and four of the six firefighting tasks (charged hose advance, rake, hose rolling, static hose hold). Black out hose and lateral repositioning were adversely affected in the HOT + SR group. Working in hot conditions did not appear to consistently impair firefighters work performance, physiology, and perceptual responses. Future research should determine whether such findings remain true when individual tasks are performed over longer durations.
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