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Deshayes TA, Hsouna H, Braham MAA, Arvisais D, Pageaux B, Ouellet C, Jay O, Maso FD, Begon M, Saidi A, Gendron P, Gagnon D. Work-rest regimens for work in hot environments: A scoping review. Am J Ind Med 2024; 67:304-320. [PMID: 38345435 DOI: 10.1002/ajim.23569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/08/2024] [Accepted: 01/23/2024] [Indexed: 03/16/2024]
Abstract
BACKGROUND To limit exposures to occupational heat stress, leading occupational health and safety organizations recommend work-rest regimens to prevent core temperature from exceeding 38°C or increasing by ≥1°C. This scoping review aims to map existing knowledge of the effects of work-rest regimens in hot environments and to propose recommendations for future research based on identified gaps. METHODS We performed a search of 10 databases to retrieve studies focused on work-rest regimens under hot conditions. RESULTS Forty-nine articles were included, of which 35 were experimental studies. Most studies were conducted in laboratory settings, in North America (71%), on healthy young adults, with 94% of the 642 participants being males. Most studies (66%) employed a protocol duration ≤240 min (222 ± 162 min, range: 37-660) and the time-weighted average wet-bulb globe temperature was 27 ± 4°C (range: 18-34). The work-rest regimens implemented were those proposed by the American Conference of Governmental and Industrial Hygiene (20%), National Institute of Occupational Safety and Health (11%), or the Australian Army (3%). The remaining studies (66%) did not mention how the work-rest regimens were derived. Most studies (89%) focused on physical tasks only. Most studies (94%) reported core temperature, whereas only 22% reported physical and/or mental performance outcomes, respectively. Of the 35 experimental studies included, 77% indicated that core temperature exceeded 38°C. CONCLUSIONS Although work-rest regimens are widely used, few studies have investigated their physiological effectiveness. These studies were mainly short in duration, involved mostly healthy young males, and rarely considered the effect of work-rest regimens beyond heat strain during physical exertion.
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Affiliation(s)
- Thomas A Deshayes
- Montreal Heart Institute, Montréal, Québec, Canada
- École de kinésiologie et des sciences de l'activité physique (EKSAP), Faculté de médecine, Université de Montréal, Montréal, Québec, Canada
| | - Hsen Hsouna
- Montreal Heart Institute, Montréal, Québec, Canada
- École de kinésiologie et des sciences de l'activité physique (EKSAP), Faculté de médecine, Université de Montréal, Montréal, Québec, Canada
| | - Mounir A A Braham
- Département des sciences de l'activité physique, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
- Département d'anatomie, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
| | - Denis Arvisais
- Bibliothèque des sciences de la santé, Université de Montréal, Montréal, Québec, Canada
| | - Benjamin Pageaux
- École de kinésiologie et des sciences de l'activité physique (EKSAP), Faculté de médecine, Université de Montréal, Montréal, Québec, Canada
- Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montréal, Québec, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage (CIRCA), Montréal, Québec, Canada
| | - Capucine Ouellet
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), Montréal, Québec, Canada
| | - Ollie Jay
- Heat and Health Research Incubator, University of Sydney, Sydney, New South Wales, Australia
| | - Fabien D Maso
- École de kinésiologie et des sciences de l'activité physique (EKSAP), Faculté de médecine, Université de Montréal, Montréal, Québec, Canada
- Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage (CIRCA), Montréal, Québec, Canada
| | - Mickael Begon
- École de kinésiologie et des sciences de l'activité physique (EKSAP), Faculté de médecine, Université de Montréal, Montréal, Québec, Canada
- Centre de recherche du CHU Sainte-Justine, Montréal, Québec, Canada
| | - Alireza Saidi
- Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST), Montréal, Québec, Canada
| | - Philippe Gendron
- Département des sciences de l'activité physique, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada
| | - Daniel Gagnon
- Montreal Heart Institute, Montréal, Québec, Canada
- École de kinésiologie et des sciences de l'activité physique (EKSAP), Faculté de médecine, Université de Montréal, Montréal, Québec, Canada
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Bachraty JP, Qiao J, Powers ES, Vandermark LW, Pryor JL, Pryor RR. Plateau in Core Temperature during Shorter but Not Longer Work/Rest Cycles in Heat. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2024; 21:371. [PMID: 38541370 PMCID: PMC10970706 DOI: 10.3390/ijerph21030371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 04/09/2024]
Abstract
This study compared physiological responses to two work/rest cycles of a 2:1 work-to-rest ratio in a hot environment. In a randomized crossover design, fourteen participants completed 120 min of walking and rest in the heat (36.3 ± 0.6 °C, 30.2 ± 4.0% relative humidity). Work/rest cycles were (1) 40 min work/20 min rest [40/20], or (2) 20 min work/10 min rest [20/10], both completing identical work. Core temperature (Tc), skin temperature (Tsk), heart rate (HR), nude body mass, and perception of work were collected. Comparisons were made between trials at equal durations of work using three-way mixed model ANOVA. Tc plateaued in [20/10] during the second hour of work (p = 0.93), while Tc increased in [40/20] (p < 0.01). There was no difference in maximum Tc ([40/20]: 38.08 ± 0.35 °C, [20/10]: 37.99 ± 0.27 °C, p = 0.22) or end-of-work Tsk ([40/20]: 36.1 ± 0.8 °C, [20/10]: 36.0 ± 0.7 °C, p = 0.45). End-of-work HR was greater in [40/20] (145 ± 25 b·min-1) compared to [20/10] (141 ± 27 b·min-1, p = 0.04). Shorter work/rest cycles caused a plateau in Tc while longer work/rest cycles resulted in a continued increase in Tc throughout the work, indicating that either work structure could be used during shorter work tasks, while work greater than 2 h in duration may benefit from shorter work/rest cycles to mitigate hyperthermia.
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Affiliation(s)
| | | | | | | | | | - Riana R. Pryor
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY 14214, USA (J.Q.); (E.S.P.)
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Bernard TE, Ashley CD, Wolf ST, Kenney WL. Core temperature and heart rate at the upper limit of the prescriptive zone. Physiol Rep 2023; 11:e15812. [PMID: 37688426 PMCID: PMC10492005 DOI: 10.14814/phy2.15812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 08/18/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023] Open
Abstract
The expressed goal of limiting workplace heat stress exposures to a core temperature (Tc ) of 38°C traces back to a 1969 World Health Organization Technical Report (WHO Series 412). The actual goal was to limit exposures to the upper limit of the prescriptive zone (ULPZ). To explore the physiological strain at the ULPZ, progressive heat stress protocol data from Penn State University (PSU) and University of South Florida (USF) below and at the ULPZ were used to articulate the relation of Tc and heart rate (HR) to metabolic rate (MR) with consideration of acclimatization state, clothing, exposure condition (PreULPZ vs. ULPZ), and sex. Regression models demonstrated the association of MR and sex with Tc and HR. At the ULPZ, women had systematically higher values of Tc and HR than men at the same MR likely due to higher relative demands. There was no effect for acclimatization state and clothing. As expected for individuals, Tc was practically constant below the ULPZ and HR exhibited increasing values approaching the ULPZ. At 490 W, the high MR cited in the WHO document, the mean Tc for men was near the 38°C limit with systematically lower Tc at lower MRs.
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Affiliation(s)
| | - Candi D. Ashley
- Exercise Science Program, College of EducationUniversity of South FloridaTampaFLUSA
| | - S. Tony Wolf
- Department of KinesiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
- Present address:
Department of KinesiologyUniversity of GeorgiaAthensGAUSA
| | - W. Larry Kenney
- Department of KinesiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
- Graduate Program in PhysiologyThe Pennsylvania State UniversityUniversity ParkPAUSA
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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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Bernard TE, Flach JW, Ashley CD. Group Outcomes for Time-Weighted Averaging in WBGT-Based Heat Stress Exposure Assessment. Ann Work Expo Health 2023; 67:345-353. [PMID: 36454581 DOI: 10.1093/annweh/wxac083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 10/17/2022] [Accepted: 11/02/2022] [Indexed: 12/02/2022] Open
Abstract
The wet bulb globe temperature (WBGT)-based occupational exposure limits (OELs) were developed from steady exposures to heat stress at constant WBGT and metabolic rate (M). The exposure limits were based on compensable heat stress exposures at the upper limit of the prescriptive zone for most healthy people. Professional practice allows for using time-weighted averages (TWAs) of WBGT and M to account for heterogeneous heat stress exposures. The purpose of the current paper was to report on the effectiveness of time-weighted averaging to assess occupational heat stress using published studies. Our hypothesis was using TWA-WBGT and TWA-M was as protective as the recommended OELs for steady exposures. The current paper reports on 62 observations of work that alternate between at least two heat stress conditions (usually work and recovery) reported in 16 papers. The TWA-WBGT and TWA-M were determined for all observations. ΔLimit was the observed TWA-WBGT minus the exposure limit at the TWA-M based on acclimatization state. The observations were then classified as above or below ΔLimit = 0. Each observation was also classified as uncompensable if the mean core temperature for the group was greater than 38°C or a less tolerant individual was above 38.5°C. When comparing exposure classifications to outcome classifications using 2 × 2 tables, the sensitivity and specificity for all observations were 0.72 and 0.73, respectively. The sensitivity was much less than the expected value near 1.0, and the large difference called into question the ability of TWAs to represent actual heat stress. There was some suspicion that there were differences between acclimatized and unacclimatized observations. Before any of these findings are embedded in policy or practice, a more careful evaluation of TWAs is required. In conclusion, we believe that the use of TWAs for heat stress analysis was not fully evaluated, and we proposed a framework for evaluation.
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Affiliation(s)
- Thomas E Bernard
- College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - John W Flach
- College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Candi D Ashley
- Exercise Science Program, College of Education, University of South Florida, Tampa, FL 33620, USA
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Bartman NE, Larson JR, Looney DP, Johnson BD, Schlader ZJ, Hostler D, Pryor RR. Do the National Institute for Occupational Safety and Health recommendations for working in the heat prevent excessive hyperthermia and body mass loss in unacclimatized males? JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2022; 19:596-602. [PMID: 36083153 DOI: 10.1080/15459624.2022.2123493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The National Institute for Occupational Safety and Health recommendations for work in the heat suggest workers consume 237 mL of water every 15-20 min and allow for continuous work at heavy intensities in hot environments up to 34 °C and 30% relative humidity. The goal was to determine whether the National Institute for Occupational Safety and Health recommendations prevented core temperature from exceeding 38.0 °C and greater than 2% body mass loss during heavy-intensity work in the heat. Eight males consumed 237 mL of water every 20 min during 2 hr of continuous heavy-intensity walking (6.4 kph, 1% grade) in a 34 °C/30% relative humidity environment, in accordance with the National Institute for Occupational Safety and Health recommendations. Projected core temperature and percent body mass loss were calculated for 4 and 8 hr of continuous work. Core temperature rose from baseline (36.8 ± 0.3 °C) to completion of 2 hr of work (38.1 ± 0.6 °C, p < 0.01), with two participants reaching the 38.0 °C threshold. Projected core temperatures remained elevated from baseline (p < 0.01), did not change from 2 to 4 hr (38.1 ± 0.7 °C, p > 0.99) and 4 to 8 hr (38.1 ± 0.8 °C, p > 0.99), respectively, and one participant exceeded 38.0 °C at 4 to 8 hr. There was no change in body mass loss over time (p > 0.99). During 2 hr of continuous heavy-intensity work in the heat, 75% of participants did not reach 38 °C core temperature and 88% did not reach 2% body mass loss when working to National Institute for Occupational Safety and Health recommendations.
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Affiliation(s)
- Nathan E Bartman
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, SUNY, Buffalo, New York
| | - Jonathan R Larson
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, SUNY, Buffalo, New York
| | - David P Looney
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Blair D Johnson
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Zachary J Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - David Hostler
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, SUNY, Buffalo, New York
| | - Riana R Pryor
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, SUNY, Buffalo, New York
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7
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Zhao M, Zhao J, Yan J, Gao X. The Evaluation of Physiological Index Changes and Safety Work of Female Medical Staff With Different Medical Protection Standards in the Ward of COVID-19. Front Med (Lausanne) 2022; 9:906140. [PMID: 35814785 PMCID: PMC9256920 DOI: 10.3389/fmed.2022.906140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/25/2022] [Indexed: 11/13/2022] Open
Abstract
Background Effective personal protective equipment (PPE) contribute to the prevention of COVID-19 infection. However, it is necessary to evaluate the potential risk of different medical protections in the isolation ward of COVID-19. Objectives We aimed to explore the dynamics in physiological indexes of medical staff under primary and secondary PPE in the isolation ward of COVID-19 and provide the scientific basis for determining the safe work strategy. Materials and Methods In this study, 30 female nurses were selected to simulate medical work under the primary or secondary PPE, respectively. The oral temperature, axillary temperature, heart rate, respiratory rate, blood oxygen saturation, and blood pressure were measured and recorded every 20 min. The subjective adverse symptoms were recorded every 30 min. The blood glucose and weight of the individuals were measured and recorded before and after the trial. Results The results indicated that the median trial persistence time in the participants with moderate-intensity work wearing the secondary PPE (70.0 min) was much lower than that with moderate-intensity work wearing the primary PPE (180 min) and with light-intensity work wearing the primary PPE (110 min; p < 0.05). Importantly, the heart rate, oral/axillary temperature, and respiratory rate of physiological indexes of the participants under moderate-intensity work wearing the secondary PPE increased significantly faster than the primary PPE (p < 0.001), while blood oxygen saturation decreased significantly faster than the primary PPE (p < 0.001). In addition, the proportions of subjective adverse symptoms (such as dry mouth, dizziness, palpitations, and anhelation) were much higher than primary PPE (p < 0.001). The average sweat volume and blood glucose consumption of participants under moderate-intensity work wearing primary PPE were higher than secondary PPE (p < 0.001). Conclusion The combination of an exacerbated workload and secondary PPE worn by COVID-19 healthcare workers increases the change in physiological indicators, and in some cases the adverse symptoms, which can affect and even suspend their medical work. For any medical institution, there is room for improvement in terms of bioethics of a "Job Well Done" to reduce the risks of medical activities under secondary PPE.
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Affiliation(s)
- Min Zhao
- Department of Internal Medicine, Fuzhou Pulmonary Hospital of Fujian, Fuzhou, China
| | - Jianhui Zhao
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, China
| | - Junbing Yan
- Department of Internal Medicine, Fuzhou Pulmonary Hospital of Fujian, Fuzhou, China
| | - Xiaoye Gao
- Department of Internal Medicine, Fuzhou Pulmonary Hospital of Fujian, Fuzhou, China
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8
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Bongers CCWG, de Korte JQ, Zwartkruis M, Levels K, Kingma BRM, Eijsvogels TMH. Heat Strain and Use of Heat Mitigation Strategies among COVID-19 Healthcare Workers Wearing Personal Protective Equipment-A Retrospective Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19031905. [PMID: 35162925 PMCID: PMC8834922 DOI: 10.3390/ijerph19031905] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/28/2022] [Accepted: 02/04/2022] [Indexed: 12/19/2022]
Abstract
The combination of an exacerbated workload and impermeable nature of the personal protective equipment (PPE) worn by COVID-19 healthcare workers increases heat strain. We aimed to compare the prevalence of heat strain symptoms before (routine care without PPE) versus during the COVID-19 pandemic (COVID-19 care with PPE), identify risk factors associated with experiencing heat strain, and evaluate the access to and use of heat mitigation strategies. Dutch healthcare workers (n = 791) working at COVID-19 wards for ≥1 week, completed an online questionnaire to assess personal characteristics, heat strain symptoms before and during the COVID-19 pandemic, and the access to and use of heat mitigation strategies. Healthcare workers experienced ~25× more often heat strain symptoms during medical duties with PPE (93% of healthcare workers) compared to without PPE (30% of healthcare workers; OR = 25.57 (95% CI = 18.17-35.98)). Female healthcare workers and those with an age <40 years were most affected by heat strain, whereas exposure time and sports activity level were not significantly associated with heat strain prevalence. Cold drinks and ice slurry ingestion were the most frequently used heat mitigation strategies and were available in 63.5% and 30.1% of participants, respectively. Our findings indicate that heat strain is a major challenge for COVID-19 healthcare workers, and heat mitigations strategies are often used to counteract heat strain.
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Affiliation(s)
- Coen C. W. G. Bongers
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Philips van Leijdenlaan 15, 6525 EX Nijmegen, The Netherlands; (C.C.W.G.B.); (J.Q.d.K.); (M.Z.)
| | - Johannus Q. de Korte
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Philips van Leijdenlaan 15, 6525 EX Nijmegen, The Netherlands; (C.C.W.G.B.); (J.Q.d.K.); (M.Z.)
| | - Mike Zwartkruis
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Philips van Leijdenlaan 15, 6525 EX Nijmegen, The Netherlands; (C.C.W.G.B.); (J.Q.d.K.); (M.Z.)
| | - Koen Levels
- Institute of Training Medicine and Training Physiology, TGTF, Royal Netherlands Army, Herculeslaan 1, 3584 AB Utrecht, The Netherlands;
| | - Boris R. M. Kingma
- Department of Human Performance, Unit Defence, Safety and Security, TNO, The Netherlands Organization for Applied Sciences, Kampweg 55, 3769 DE Soesterberg, The Netherlands;
- Department of Energy Technology, Eindhoven University of Technology, Groene Loper 19, 5612 AP Eindhoven, The Netherlands
| | - Thijs M. H. Eijsvogels
- Department of Physiology, Radboud Institute for Health Sciences, Radboud University Medical Center, Philips van Leijdenlaan 15, 6525 EX Nijmegen, The Netherlands; (C.C.W.G.B.); (J.Q.d.K.); (M.Z.)
- Correspondence: ; Tel.: +31-2436-13674
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9
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Bonell A, Nadjm B, Samateh T, Badjie J, Perry-Thomas R, Forrest K, Prentice AM, Maxwell NS. Impact of Personal Cooling on Performance, Comfort and Heat Strain of Healthcare Workers in PPE, a Study From West Africa. Front Public Health 2021; 9:712481. [PMID: 34540787 PMCID: PMC8440920 DOI: 10.3389/fpubh.2021.712481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 08/10/2021] [Indexed: 01/25/2023] Open
Abstract
Background: Personal protective equipment (PPE) is an essential component of safely treating suspected or confirmed SARS-CoV-2 patients. PPE acts as a barrier to heat loss, therefore increasing the risk of thermal strain which may impact on cognitive function. Healthcare workers (HCWs) need to be able to prioritize and execute complex tasks effectively to ensure patient safety. This study evaluated pre-cooling and per-cooling methods on thermal strain, thermal comfort and cognitive function during simulated emergency management of an acutely unwell patient. Methods: This randomized controlled crossover trial was run at the Clinical Services Department of the Medical Research Unit The Gambia. Each participant attended two sessions (Cool and Control) in standard PPE. Cool involved pre-cooling with an ice slurry ingestion and per-cooling by wearing an ice-vest external to PPE. Results: Twelve participants completed both sessions. There was a significant increase in tympanic temperature in Control sessions at both 1 and 2 h in PPE (p = 0.01). No significant increase was seen during Cool. Effect estimate of Cool was -0.2°C (95% CI -0.43; 0.01, p = 0.06) post 1 h and -0.28°C (95% CI -0.57; 0.02, p = 0.06) post 2 h on tympanic temperature. Cool improved thermal comfort (p < 0.001), thermal sensation (p < 0.001), and thirst (p = 0.04). No difference on cognitive function was demonstrated using multilevel modeling. Discussion: Thermal strain in HCWs wearing PPE can be safely reduced using pre- and per-cooling methods external to PPE.
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Affiliation(s)
- Ana Bonell
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
- Centre on Climate Change and Planetary Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Behzad Nadjm
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Tida Samateh
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Jainaba Badjie
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Robyn Perry-Thomas
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Karen Forrest
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Andrew M. Prentice
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Neil S. Maxwell
- Environmental Extremes Laboratory, University of Brighton, Eastbourne, United Kingdom
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10
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Sippli K, Schmalzried P, Rieger MA, Voelter-Mahlknecht S. Challenges arising for older workers from participating in a workplace intervention addressing work ability: a qualitative study from Germany. Int Arch Occup Environ Health 2021; 94:919-933. [PMID: 33491100 PMCID: PMC8238737 DOI: 10.1007/s00420-020-01639-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 12/18/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Studies examining what renders workplace interventions to sustain and promote work ability of older workers successful have largely neglected older workers´ perspective. This paper outlines the results of a study with regard to older workers´ experiences and expectations of a workplace intervention. Based on these findings, some reflections on how to improve the design and the implementation of workplace interventions for older workers are provided. METHODS Semi-structured interviews were conducted with older workers (N = 8) participating in a workplace intervention undertaken at one production site of a large manufacturing company in Baden-Wurttemberg/Germany. The interview guide included questions on participants´ experiences with and expectations of the intervention. The interviews were recorded, transcribed verbatim and analyzed using qualitative content analysis according to Mayring (2014). RESULTS Older workers´ reported some challenges they face due to their participation in the workplace intervention. These resulted from the work environment (physical challenges), the work process design (new long work cycle), the work organization (tight time allowances, little job rotation, change of teams, age stereotypes) and the management of the workplace intervention (bad information, feeling of occupational insecurity and lack of being valued). CONCLUSIONS The study shows that challenges arising for older workers from their participation in the workplace intervention may have counteracted the promotion of work ability. As findings suggest, some of these challenges might have been avoided either by considering workers´ perspective during design and implementation of an intervention or by referring to evidence on aging and work ability.
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Affiliation(s)
- Khira Sippli
- Institute of Occupational and Social Medicine and Health Services Research, University Hospital Tuebingen, Wilhelmstraße 27, 72074, Tübingen, Germany
- Institute for Applied Economic Research at the University Tuebingen, Schaffhausenstr. 73, 72072, Tuebingen, Germany
| | - Pia Schmalzried
- Institute of Occupational and Social Medicine and Health Services Research, University Hospital Tuebingen, Wilhelmstraße 27, 72074, Tübingen, Germany
| | - Monika A Rieger
- Institute of Occupational and Social Medicine and Health Services Research, University Hospital Tuebingen, Wilhelmstraße 27, 72074, Tübingen, Germany
| | - Susanne Voelter-Mahlknecht
- Institute of Occupational and Social Medicine and Health Services Research, University Hospital Tuebingen, Wilhelmstraße 27, 72074, Tübingen, Germany.
- Institute of Occupational Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Augustenburger Platz 1, 13353, Berlin, Germany.
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11
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Ioannou LG, Mantzios K, Tsoutsoubi L, Nintou E, Vliora M, Gkiata P, Dallas CN, Gkikas G, Agaliotis G, Sfakianakis K, Kapnia AK, Testa DJ, Amorim T, Dinas PC, Mayor TS, Gao C, Nybo L, Flouris AD. Occupational Heat Stress: Multi-Country Observations and Interventions. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:6303. [PMID: 34200783 PMCID: PMC8296111 DOI: 10.3390/ijerph18126303] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/25/2021] [Accepted: 06/07/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND Occupational heat exposure can provoke health problems that increase the risk of certain diseases and affect workers' ability to maintain healthy and productive lives. This study investigates the effects of occupational heat stress on workers' physiological strain and labor productivity, as well as examining multiple interventions to mitigate the problem. METHODS We monitored 518 full work-shifts obtained from 238 experienced and acclimatized individuals who work in key industrial sectors located in Cyprus, Greece, Qatar, and Spain. Continuous core body temperature, mean skin temperature, heart rate, and labor productivity were collected from the beginning to the end of all work-shifts. RESULTS In workplaces where self-pacing is not feasible or very limited, we found that occupational heat stress is associated with the heat strain experienced by workers. Strategies focusing on hydration, work-rest cycles, and ventilated clothing were able to mitigate the physiological heat strain experienced by workers. Increasing mechanization enhanced labor productivity without increasing workers' physiological strain. CONCLUSIONS Empowering laborers to self-pace is the basis of heat mitigation, while tailored strategies focusing on hydration, work-rest cycles, ventilated garments, and mechanization can further reduce the physiological heat strain experienced by workers under certain conditions.
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Affiliation(s)
- Leonidas G. Ioannou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, 2100 Copenhagen, Denmark;
| | - Konstantinos Mantzios
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Lydia Tsoutsoubi
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Eleni Nintou
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Maria Vliora
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Paraskevi Gkiata
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Constantinos N. Dallas
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Giorgos Gkikas
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Gerasimos Agaliotis
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Kostas Sfakianakis
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Areti K. Kapnia
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Davide J. Testa
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Tânia Amorim
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Petros C. Dinas
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
| | - Tiago S. Mayor
- SIMTECH Laboratory, Transport Phenomena Research Centre, Engineering Faculty of Porto University, 4200-465 Porto, Portugal;
| | - Chuansi Gao
- Thermal Environment Laboratory, Division of Ergonomics and Aerosol Technology, Department of Design Sciences, Faculty of Engineering, Lund University, 22100 Lund, Sweden;
| | - Lars Nybo
- Department of Nutrition, Exercise and Sports, August Krogh Building, University of Copenhagen, 2100 Copenhagen, Denmark;
| | - Andreas D. Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, 42100 Trikala, Greece; (L.G.I.); (K.M.); (L.T.); (E.N.); (M.V.); (P.G.); (C.N.D.); (G.G.); (G.A.); (K.S.); (A.K.K.); (D.J.T.); (T.A.); (P.C.D.)
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12
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Hinchliffe A, Kogevinas M, Pérez-Gómez B, Ardanaz E, Amiano P, Marcos-Delgado A, Castaño-Vinyals G, Llorca J, Moreno V, Alguacil J, Fernandez-Tardón G, Salas D, Marcos-Gragera R, Aragonés N, Guevara M, Gil L, Martin V, Benavente Y, Gomez-Acebo I, Santibáñez M, Ángel Alba M, García AM, Pollán M, Turner MC. Occupational Heat Exposure and Breast Cancer Risk in the MCC-Spain Study. Cancer Epidemiol Biomarkers Prev 2020; 30:364-372. [PMID: 33268491 DOI: 10.1158/1055-9965.epi-20-0732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/30/2020] [Accepted: 11/25/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Mechanisms linking occupational heat exposure with chronic diseases have been proposed. However, evidence on occupational heat exposure and cancer risk is limited. METHODS We evaluated occupational heat exposure and female breast cancer risk in a large Spanish case-control study. We enrolled 1,738 breast cancer cases and 1,910 frequency-matched population controls. A Spanish job-exposure matrix, MatEmEsp, was used to assign estimates of the proportion of workers exposed (P ≥ 25% for at least 1 year) and work time with heat stress (wet bulb globe temperature ISO 7243) for each occupation. We used three exposure indices: ever versus never exposed, lifetime cumulative exposure, and duration of exposure (years). We estimated ORs and 95% confidence intervals (CI), applying a lag period of 5 years and adjusting for potential confounders. RESULTS Ever occupational heat exposure was associated with a moderate but statistically significant higher risk of breast cancer (OR 1.22; 95% CI, 1.01-1.46), with significant trends across categories of lifetime cumulative exposure and duration (P trend = 0.01 and 0.03, respectively). Stronger associations were found for hormone receptor-positive disease (OR ever exposure = 1.38; 95% CI, 1.12-1.67). We found no confounding effects from multiple other common occupational exposures; however, results attenuated with adjustment for occupational detergent exposure. CONCLUSIONS This study provides some evidence of an association between occupational heat exposure and female breast cancer risk. IMPACT Our results contribute substantially to the scientific literature. Further investigations are needed considering multiple occupational exposures.
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Affiliation(s)
- Alice Hinchliffe
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Manolis Kogevinas
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - Beatriz Pérez-Gómez
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Cancer and Environmental Epidemiology Unit, Department of Epidemiology of Chronic Diseases, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain
| | - Eva Ardanaz
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Instituto de Salud Pública de Navarra (IdiSNA), Pamplona, Spain
| | - Pilar Amiano
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Public Health Division of Gipuzkoa, Biodonostia Health Research Institute, Ministry of Health of the Basque Government, San Sebastian, Spain
| | | | - Gemma Castaño-Vinyals
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - Javier Llorca
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,University of Cantabria - IDIVAL, Santander, Spain
| | - Víctor Moreno
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Oncology Data Analytics Program (ODAP), Catalan Institute of Oncology (ICO) and Oncobell Program, Bellvitge Biomedical Research Institute (IDIBELL), Hospital Duran i Reynals, Barcelona, Spain.,Department of Clinical Sciences, Faculty of Medicine, University of Barcelona, Barcelona, Spain
| | - Juan Alguacil
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Centro de Investigación en Recursos Naturales, Salud y Medio Ambiente (RENSMA), Universidad de Huelva, Huelva, Spain
| | - Guillermo Fernandez-Tardón
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Institute of Health Research of the Principality of Asturias (ISPA), Public Health Department, University of Oviedo, Oviedo, Spain
| | - Dolores Salas
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Foundation for the Promotion of Health and Biomedical Research of Valencia Region (FISABIO), Valencia, Spain.,General Directorate Public Health, Valencian Community, Valencia, Spain
| | - Rafael Marcos-Gragera
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Epidemiology Unit and Girona Cancer Registry, Oncology Coordination Plan, Department of Health, Autonomous Government of Catalonia, Catalan Institute of Oncology, Girona, Spain.,Descriptive Epidemiology, Genetics and Cancer Prevention Group, Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Nuria Aragonés
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Epidemiology Section, Public Health Division, Department of Health of Madrid, Madrid, Spain
| | - Marcela Guevara
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Instituto de Salud Pública de Navarra (IdiSNA), Pamplona, Spain
| | - Leire Gil
- Public Health Division of Gipuzkoa, Biodonostia Health Research Institute, Ministry of Health of the Basque Government, San Sebastian, Spain
| | - Vicente Martin
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Instituto de Biomedicina (IBIOMED)
| | - Yolanda Benavente
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Unit of Infections and Cancer (UNIC), Cancer Epidemiology Research Programme, IDIBELL, Institut Català d'Oncologia, L'Hospitalet De Llobregat, Barcelona, Spain
| | - Ines Gomez-Acebo
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,University of Cantabria - IDIVAL, Santander, Spain
| | | | - Miguel Ángel Alba
- Industrial Hygiene Department, Quirón Prevención, S.L.U., Barcelona, Barcelona, Spain
| | - Ana M García
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Departamento de Medicina Preventiva y Salud Pública, Universitat de València, València, Spain.,Center for Research in Occupational Health (CISAL), Universitat Pompeu Fabra, Barcelona, Spain
| | - Marina Pollán
- Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,Cancer and Environmental Epidemiology Unit, Department of Epidemiology of Chronic Diseases, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain
| | - Michelle C Turner
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain. .,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Consortium for Biomedical Research in Epidemiology and Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Madrid, Spain.,McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Canada
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13
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Kaltsatou A, Flouris AD, Herry CL, Notley SR, Macartney MJ, Seely AJE, Kenny GP. Heart rate variability in older workers during work under the Threshold Limit Values for heat exposure. Am J Ind Med 2020; 63:787-795. [PMID: 32677129 DOI: 10.1002/ajim.23156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/30/2020] [Accepted: 07/01/2020] [Indexed: 11/11/2022]
Abstract
BACKGROUND The Threshold Limit Values (TLV) of the American Conference of Governmental and Industrial Hygienists indicate the levels of heat stress that all workers may be repeatedly exposed to without adverse health effects. In this study, we evaluated heart rate variability (HRV) during moderate-to-heavy work performed continuously or according to different TLV work-rest (WR) allocations in healthy physically active older workers. METHODS Nine healthy older (58 ± 5 years) males performed three different 120-minute conditions in accordance with TLV guidelines for moderate-to-heavy intensity work (360 W fixed rate of heat production) in different wet-bulb globe temperatures (WBGT): continuous cycling at 28°C WBGT (CON), as well as intermitted work performed at WR of 3:1 in 29°C WBGT (WR3:1), and at WR of 1:1 at 30°C (WR1:1). Rectal temperature and HRV (3-lead electrocardiogram [ECG]) were assessed throughout. RESULTS Coefficient of Variation, Poincaré SD2, and Shannon Entropy were decreased during the CON compared with the WR3:1 when core temperature exceeded 38°C and after 1 hour of continuous work (P < .05). Also, 4 of the 12 HRV indices studied were reduced at CON compared with WR1:1 after 2 hours of accumulated work time (P < .05). Participants worked longer before core temperature reached 38°C during the WR1:1 and the WR3:1, compared with CON (P < .05). CONCLUSIONS Incorporating breaks during moderate-to-heavy work in the heat for older adults can reduce autonomic stress and prolong the work performed at safe core temperature levels. The TLV WR1:1 provides increased cardiac protection for older workers, as compared with the CON and the WR3:1.
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Affiliation(s)
- Antonia Kaltsatou
- FAME Laboratory, Department of Exercise ScienceUniversity of ThessalyTrikala Greece
| | - Andreas D. Flouris
- FAME Laboratory, Department of Exercise ScienceUniversity of ThessalyTrikala Greece
- Human and Environmental Physiology Research Unit, School of Human KineticsUniversity of Ottawa Canada
| | - Christophe L. Herry
- Division of Thoracic Surgery and Critical Care MedicineOttawa HospitalOttawa Ontario Canada
| | - Sean R. Notley
- Human and Environmental Physiology Research Unit, School of Human KineticsUniversity of Ottawa Canada
| | - Michael J. Macartney
- School of Health Sciences, College of Health and MedicineUniversity of TasmaniaHobart Tasmania Australia
| | - Andrew J. E. Seely
- Division of Thoracic Surgery and Critical Care MedicineOttawa HospitalOttawa Ontario Canada
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human KineticsUniversity of Ottawa Canada
- Clinical Epidemiology ProgramOttawa Hospital Research InstituteOttawa Ontario Canada
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14
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Holistic approach to assess co-benefits of local climate mitigation in a hot humid region of Australia. Sci Rep 2020; 10:14216. [PMID: 32848173 PMCID: PMC7450084 DOI: 10.1038/s41598-020-71148-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 08/10/2020] [Indexed: 11/08/2022] Open
Abstract
Overheated outdoor environments adversely impact urban sustainability and livability. Urban areas are particularly affected by heat waves and global climate change, which is a serious threat due to increasing heat stress and thermal risk for residents. The tropical city of Darwin, Australia, for example, is especially susceptible to urban overheating that can kill inhabitants. Here, using a modeling platform supported by detailed measurements of meteorological data, we report the first quantified analysis of the urban microclimate and evaluate the impacts of heat mitigation technologies to decrease the ambient temperature in the city of Darwin. We present a holistic study that quantifies the benefits of city-scale heat mitigation to human health, energy consumption, and peak electricity demand. The best-performing mitigation scenario, which combines cool materials, shading, and greenery, reduces the peak ambient temperature by 2.7 °C and consequently decreases the peak electricity demand and the total annual cooling load by 2% and 7.2%, respectively. Further, the proposed heat mitigation approach can save 9.66 excess deaths per year per 100,000 people within the Darwin urban health district. Our results confirm the technological possibilities for urban heat mitigation, which serves as a strategy for mitigating the severity of cumulative threats to urban sustainability.
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15
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Notley SR, Flouris AD, Kenny GP. Occupational heat stress management: Does one size fit all? Am J Ind Med 2019; 62:1017-1023. [PMID: 30791115 DOI: 10.1002/ajim.22961] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 02/21/2019] [Accepted: 03/04/2019] [Indexed: 01/20/2023]
Abstract
Heat stress is a deadly occupational hazard that is projected to increase in severity with global warming. While upper limits for heat stress designed to protect all workers have been recommended by occupational safety institutes for some time, heat stress continues to compromise health and productivity. In our view, this is largely explained by the inability of existing guidelines to consider the inter-individual (age, sex, disease, others) and intra-individual (medication use, fitness, hydration, others) factors that cause extensive variability in physiological tolerance to a given heat stress. In conditions that do not exceed the recommended limits, this 'one size fits all' approach to heat stress management can lead to reductions in productivity in more heat-tolerant workers, while compromising safety in less heat-tolerant workers who may develop heat-related illness, even in temperate conditions. Herein, we discuss future directions in occupational heat stress management that consider this individual variability.
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Affiliation(s)
- Sean R. Notley
- Human and Environmental Physiology Research UnitSchool of Human Kinetics, University of Ottawa OttawaCanada
| | - Andreas D. Flouris
- Human and Environmental Physiology Research UnitSchool of Human Kinetics, University of Ottawa OttawaCanada
- FAME LaboratoryDepartment of Exercise Science, University of Thessaly TrikalaGreece
| | - Glen P. Kenny
- Human and Environmental Physiology Research UnitSchool of Human Kinetics, University of Ottawa OttawaCanada
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16
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Ioannou LG, Tsoutsoubi L, Mantzios K, Flouris AD. A free software to predict heat strain according to the ISO 7933:2018. INDUSTRIAL HEALTH 2019; 57:711-720. [PMID: 30918161 PMCID: PMC6885605 DOI: 10.2486/indhealth.2018-0216] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Our primary objective in this study was to design and implement the FAME Lab PHS Calculator software (PHSFL) (www.famelab.gr/research/downloads), a free tool to calculate the predicted heat strain of an individual based on ISO 7933:2018. Our secondary objective was to optimize the practicality of the PHSFL by incorporating knowledge from other ISO standards and published literature. The third objective of this study was to assess: (i) the criterion-related validity of the PHSFL by comparing its results against those obtained using the original ISO 7933:2018 code; and (ii) the construct validity of the PHSFL by comparing its results against those obtained via field experiments performed in human participants during work in the heat. Our analysis for criterion validity demonstrates that PHSFL provides valid results within the required computational accuracy, according to Annex F of ISO 7933:2018. The construct validity showed that root mean square errors (RMSE) and 95% limits of agreement (LOA) were minimal between measured and predicted core temperature (RMSE: 0.3°C; LOA: 0.06 ± 0.58°C) and small between measured and predicted mean skin temperature (RMSE: 1.1°C; LOA: 0.59 ± 1.83°C). In conclusion, the PHSFL software demonstrated strong criterion-related and construct-related validity.
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Affiliation(s)
- Leonidas G Ioannou
- FAME Laboratory, School of Exercise Science, University of Thessaly, Greece
| | - Lydia Tsoutsoubi
- FAME Laboratory, School of Exercise Science, University of Thessaly, Greece
| | | | - Andreas D Flouris
- FAME Laboratory, School of Exercise Science, University of Thessaly, Greece
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17
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Seo Y, Powell J, Strauch A, Roberge R, Kenny GP, Kim JH. Heat stress assessment during intermittent work under different environmental conditions and clothing combinations of effective wet bulb globe temperature (WBGT). JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2019; 16:467-476. [PMID: 31107182 PMCID: PMC7970242 DOI: 10.1080/15459624.2019.1612523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This study examined whether different combinations of ambient temperature and relative humidity for the effective wet bulb globe temperature, in conjunction with two different levels of clothing adjustment factors, elicit a similar level of heat strain consistent with the current threshold limit value guidelines. Twelve healthy, physically active men performed four 15-min sessions of cycling at a fixed rate of metabolic heat production of 350 watts. Each trial was separated by a 15-min recovery period under four conditions: (1) Cotton coveralls + dry condition (WD: 45.5 °C dry-bulb, 15% relative humidity); (2) Cotton coveralls + humid condition (WH: 31 °C dry-bulb, 84% relative humidity); (3) Protective clothing + dry condition (PD: 30 °C dry-bulb, 15% relative humidity); and (4) Protective clothing + humid condition (PH: 20 °C dry-bulb, 80% relative humidity). Gloves (mining or chemical) and headgear (helmet or powered air-purifying respirator) were removed during recovery with hydration ad libitum. Rectal temperature (Tre), skin temperature (Tsk), physiological heat strain (PSI), perceptual heat strain (PeSI), and body heat content were calculated. At the end of the 2-hr trials, Tre remained below 38 °C and the magnitude of Tre elevation was not greater than 1 °C in all conditions (WD: 0.9, WH: 0.8, WH: 0.7, and PD: 0.6 °C). However, Tsk was significantly increased by approximately 2.1 ± 0.8 °C across all conditions (all p ≤ 0.001). The increase in Tsk was the highest in WD followed by PD, WH, and PH conditions (all p ≤ 0.001). Although PSI and PeSI did not indicate severe heat strain during the 2-hr intermittent work period, PSI and PeSI were significantly increased over time (p ≤ 0.001). This study showed that core temperature and heat strain indices (PSI and PeSI) increased similarly across the four conditions. However, given that core temperature increased continuously during the work session, it is likely that the American Conference of Governmental Industrial Hygienist's TLV® upper limit core temperature of 38.0 °C may be surpassed during extended work periods under all conditions.
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Affiliation(s)
- Yongsuk Seo
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Pittsburgh, Pennsylvania
| | - Jeffrey Powell
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Pittsburgh, Pennsylvania
| | - Amanda Strauch
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Pittsburgh, Pennsylvania
| | - Raymond Roberge
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Pittsburgh, Pennsylvania
| | - Glen P. Kenny
- Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Jung-Hyun Kim
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory, Pittsburgh, Pennsylvania
- Department of Sports Medicine, College of Physical Education, Kyung Hee University, Yongin-si, Gyeonggi-do, South Korea
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NOTLEY SEANR, MEADE ROBERTD, D’SOUZA ANDREWW, FRIESEN BRIANJ, KENNY GLENP. Heat Loss Is Impaired in Older Men on the Day after Prolonged Work in the Heat. Med Sci Sports Exerc 2018; 50:1859-1867. [DOI: 10.1249/mss.0000000000001643] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Notley SR, Flouris AD, Kenny GP. On the use of wearable physiological monitors to assess heat strain during occupational heat stress. Appl Physiol Nutr Metab 2018; 43:869-881. [DOI: 10.1139/apnm-2018-0173] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Workers in many industries are required to perform arduous work in high heat-stress conditions, which can lead to rapid increases in body temperature that elevate the risk of heat-related illness and even death. Traditionally, effort to mitigate work-related heat injury has been directed toward the assessment of environmental heat stress (e.g., wet-bulb globe temperature), rather than toward the associated physiological strain responses (e.g., heart rate and skin and core temperatures). However, because a worker’s physiological response to a given heat stress is modified independently by inter-individual factors (e.g., age, sex, chronic disease, others) and intra-individual factors both within (e.g., medication use, fitness, acclimation and hydration state, others) and beyond (e.g., shift duration, illness, others) the worker’s control, it becomes challenging to protect workers on an individual basis from heat-related injury without assessing those physiological responses. Recent advancements in wearable technology have made it possible to monitor one or more physiological indices of heat strain. Nonetheless, information on the utility of the wearable systems available for assessing occupational heat strain is unavailable. This communication is therefore directed toward identifying the physiological indices of heat strain that may be quantified in the workplace and evaluating the wearable monitoring systems available for assessing those responses. Finally, emphasis is placed on the barriers associated with implementing these devices to assist in mitigating work-related heat injury. This information is fundamental for protecting worker health and could also be utilized to prevent heat illnesses in vulnerable people during leisure or athletic activities.
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Affiliation(s)
- Sean R. Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Andreas D. Flouris
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Functional Architecture of Mammals in their Environment (FAME) Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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NOTLEY SEANR, MEADE ROBERTD, FRIESEN BRIANJ, D’SOUZA ANDREWW, KENNY GLENP. Does a Prolonged Work Day in the Heat Impair Heat Loss on the Next Day in Young Men? Med Sci Sports Exerc 2018; 50:318-326. [DOI: 10.1249/mss.0000000000001444] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Abstract
PURPOSE We evaluated physiological responses during exercise at a fixed evaporative requirement for heat balance (Ereq) but varying combinations of metabolic and environmental heat load. METHODS Nine healthy, physically active males (age: 46 ± 8 yr) performed four experimental sessions consisting of 75 min of semirecumbent cycling at various ambient temperatures. Whole-body dry heat loss (direct calorimetry) was monitored continuously as was heat production (indirect calorimetry), which was adjusted to achieve an Ereq of 400 W. The resultant metabolic heat productions and ambient temperatures for the sessions were as follows: (i) 440 W and 30°C (440 [30]), (ii) 388 W and 35°C (388 [35]), (iii) 317 W and 40°C (317 [40]), and (iv) 258 W and 45°C (258 [45]). Whole-body evaporative heat loss was determined via direct calorimetry. Esophageal (Tes) and mean skin (Tsk) temperatures as well as HR were monitored continuously. Mean body temperature (Tb) was calculated from Tes and Tsk. Physiological strain index (PSI) was determined from Tes and HR. RESULTS End-exercise evaporative heat loss and Tb were similar between conditions (both P ≥ 0.48). Tes was greater in 440 [30] (37.67°C ± 0.04°C) and 388 [35] (37.58°C ± 0.07°C) relative to both 317 [40] (37.35°C ± 0.06°C) and 258 [45] (37.20°C ± 0.07°C; all P ≤ 0.05). Further, Tsk was different between each condition (440 [30], 33.85°C ± 0.16°C; 388 [35], 34.53°C ± 0.08°C; 317 [40], 35.67°C ± 0.07°C; and 258 [45], 36.54°C ± 0.08°C; all P < 0.01). In 440 [30], HR was elevated by about 13 and 18 bpm relative to 317 [40] and 258 [45], respectively (both P < 0.01). Finally, PSI was greater in both 440 [30] and 388 [35] compared with 317 [40] and 258 [45] (all P ≤ 0.04). CONCLUSIONS Exercise at a fixed Ereq resulted in similar evaporative heat loss and Tb. However, the Tes, Tsk, HR, and PSI responses varied depending on the relative contribution of metabolic and environmental heat load.
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Affiliation(s)
- Robert D Meade
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Montpetit Hall, Ottawa, CANADA
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Flouris AD, McGinn R, Poirier MP, Louie JC, Ioannou LG, Tsoutsoubi L, Sigal RJ, Boulay P, Hardcastle SG, Kenny GP. Screening criteria for increased susceptibility to heat stress during work or leisure in hot environments in healthy individuals aged 31-70 years. Temperature (Austin) 2017; 5:86-99. [PMID: 29687046 PMCID: PMC5902215 DOI: 10.1080/23328940.2017.1381800] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 10/18/2022] Open
Abstract
Population aging and global warming generate important public health risks, as older adults have increased susceptibility to heat stress (SHS). We defined and validated sex-specific screening criteria for SHS during work and leisure activities in hot environments in individuals aged 31-70 years using age, anthropometry, and cardiorespiratory fitness. A total of 123 males and 44 females [44 ± 14 years; 22.9 ± 7.4% body fat; 40.3 ± 8.6 peak oxygen uptake (mlO2/kg/min)] participated, separated into the Analysis (n = 111) and Validation (n = 56) groups. Within these groups, participants were categorized into YOUNG (19-30 years; n = 47) and OLDER (31-70 years; n = 120). All participants performed exercise in the heat inside a direct calorimeter. Screening criteria for OLDER participants were defined from the Analysis group and were cross-validated in the Validation group. Results showed that 30% of OLDER individuals in the Analysis group were screened as SHS positive. A total of 274 statistically valid (p < 0.05) criteria were identified suggesting that OLDER participants were at risk for SHS when demonstrating two or more of the following (males/females): age ≥ 53.0/55.8 years; body mass index ≥29.5/25.7 kg/m2; body fat percentage ≥ 28.8/34.9; body surface area ≤2.0/1.7 m2; peak oxygen uptake ≤48.3/41.4 mlO2/kg fat free mass/min. In the Validation group, McNemar χ2 comparisons confirmed acceptable validity for the developed criteria. We conclude that the developed criteria can effectively screen individuals 31-70 years who are at risk for SHS during work and leisure activities in hot environments and can provide simple and effective means to mitigate the public health risks caused by heat exposure.
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Affiliation(s)
- Andreas D. Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
- Human and Environmental Physiological Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Ryan McGinn
- Human and Environmental Physiological Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Martin P. Poirier
- Human and Environmental Physiological Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Jeffrey C. Louie
- Human and Environmental Physiological Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
| | - Leonidas G. Ioannou
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Lydia Tsoutsoubi
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Ronald J. Sigal
- Human and Environmental Physiological Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
- Departments of Medicine, Cardiac Sciences, and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, Department of Human Kinetics, University of Sherbrooke, Sherbrooke, Canada
| | | | - Glen P. Kenny
- Human and Environmental Physiological Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ontario, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
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Meade RD, D'Souza AW, Krishen L, Kenny GP. The physiological strain incurred during electrical utilities work over consecutive work shifts in hot environments: A case report. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2017; 14:986-994. [PMID: 28825865 DOI: 10.1080/15459624.2017.1365151] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
PURPOSE In this article, we evaluated physiological strain in electrical utilities workers during consecutive work shifts in hot outdoor conditions. METHODS Four highly experienced electrical utilities workers were monitored during regularly scheduled work performed in hot conditions (∼34°C) on two consecutive days. Worker hydration (urine specific gravity) was assessed prior to and following work. The level of physical exertion was determined by video analysis. Body core temperature (Tcore) and heart rate (HR; presented as a percentage of maximum, %HRmax) were monitored continuously. Responses were reported for each worker individually and as a group mean ± standard deviation. RESULTS According to current guidelines, all workers were dehydrated prior to work on both days (urine specific gravity: day 1, 1.025 ± 0.005; day 2, 1.029 ± 0.004) and remained dehydrated following work (urine specific gravity: day 1, 1.027 ± 0.015; day 2, 1.032 ± 0.004) except for one worker on day 1 (urine specific gravity of 1.005). On day 1, the proportion of the work shift spent at rest (as defined by the American Conference for Governmental and Industrial Hygienists, ACGIH) was 51 ± 15% (range: 30-64%). Time spent resting increased in all workers on the second day reaching 66 ± 5% (range: 60-71%) of the work shift. Work shift average Tcore was 37.6 ± 0.1°C (range: 37.5-37.7°C) and 37.7 ± 0.2°C (range: 37.5-37.9°C) on days 1 and 2, respectively. Peak Tcore surpassed the ACGIH recommended threshold limit of 38.0°C for work in the heat in three workers on day 1 (38.1 ± 0.2°C, range: 37.8-38.2°C) while all workers exceeded this threshold on day 2 (38.4 ± 0.2°C, range: 38.2-38.7°C). By contrast, work shift average (day 1, 67 ± 7%HRmax, range: 59-74%HRmax; day 2, 65 ± 4%HRmax, range: 60-70%HRmax) and peak (day 1, 90 ± 6%HRmax, range: 83-98%HRmax; day 2, 87 ± 10%HRmax, range: 73-97%HRmax) HR were similar between days. CONCLUSION This case report demonstrates elevations in thermal strain over consecutive work shifts despite decreases in work effort in electrical utilities workers during regular work in the heat.
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Affiliation(s)
- Robert D Meade
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , ON , Canada
| | - Andrew W D'Souza
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , ON , Canada
| | - Lovely Krishen
- b Electrical Power Research Institute , Knoxville , Tennessee
| | - Glen P Kenny
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , ON , Canada
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McGinn R, Poirier MP, Louie JC, Sigal RJ, Boulay P, Flouris AD, Kenny GP. Increasing age is a major risk factor for susceptibility to heat stress during physical activity. Appl Physiol Nutr Metab 2017; 42:1232-1235. [DOI: 10.1139/apnm-2017-0322] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We evaluated the extent to which age, cardiorespiratory fitness, and body fat can independently determine whole-body heat loss (WBHL) in 87 otherwise healthy adults. We show that increasing age is a major predictor for decreasing WBHL in otherwise healthy adults (aged 20–70 years), accounting for 40% of the variation in the largest study to date. While greater body fat also had a minor detrimental impact on WBHL, there was no significant role for cardiorespiratory fitness.
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Affiliation(s)
- Ryan McGinn
- Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa; Faculty of Medicine, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Martin P. Poirier
- Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Jeffrey C. Louie
- Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Ronald J. Sigal
- Departments of Medicine, Cardiac Sciences, and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
- Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Pierre Boulay
- Faculty of Human Kinetics, University of Sherbrooke, Sherbrooke, QC J1K 0A5, Canada
| | - Andreas D. Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala 382 21, Greece
| | - Glen P. Kenny
- Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, ON K1N 6N5, Canada
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Stacey MJ, Delves SK, Britland SE, Allsopp AJ, Brett SJ, Fallowfield JL, Woods DR. Copeptin reflects physiological strain during thermal stress. Eur J Appl Physiol 2017; 118:75-84. [PMID: 29075863 PMCID: PMC5754412 DOI: 10.1007/s00421-017-3740-8] [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: 04/19/2017] [Accepted: 10/08/2017] [Indexed: 11/22/2022]
Abstract
Purpose To prevent heat-related illnesses, guidelines recommend limiting core body temperature (Tc) ≤ 38 °C during thermal stress. Copeptin, a surrogate for arginine vasopressin secretion, could provide useful information about fluid balance, thermal strain and health risks. It was hypothesised that plasma copeptin would rise with dehydration from occupational heat stress, concurrent with sympathoadrenal activation and reduced glomerular filtration, and that these changes would reflect Tc responses. Methods Volunteers (n = 15) were recruited from a British Army unit deployed to East Africa. During a simulated combat assault (3.5 h, final ambient temperature 27 °C), Tc was recorded by radiotelemetry to differentiate volunteers with maximum Tc > 38 °C versus ≤ 38 °C. Blood was sampled beforehand and afterwards, for measurement of copeptin, cortisol, free normetanephrine, osmolality and creatinine. Results There was a significant (P < 0.05) rise in copeptin from pre- to post-assault (10.0 ± 6.3 vs. 16.7 ± 9.6 pmol L−1, P < 0.001). Although osmolality did not increase, copeptin correlated strongly with osmolality after the exposure (r = 0.70, P = 0.004). In volunteers with maximum Tc > 38 °C (n = 8) vs ≤ 38 °C (n = 7) there were significantly greater elevations in copeptin (10.4 vs. 2.4 pmol L−1) and creatinine (10 vs. 2 μmol L−1), but no differences in cortisol, free normetanephrine or osmolality. Conclusions Changes in copeptin reflected Tc response more closely than sympathoadrenal markers or osmolality. Dynamic relationships with tonicity and kidney function may help to explain this finding. As a surrogate for integrated physiological strain during work in a field environment, copeptin assay could inform future measures to prevent heat-related illnesses.
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Affiliation(s)
- Michael John Stacey
- Department of Surgery and Cancer, Imperial College London, Care of General Intensive Care Unit, Hammersmith Hospital Campus, Du Cane Road, London, W12 0HS, UK. .,Department of Military Medicine, Royal Centre for Defence Medicine, ICT Building, Birmingham Research Park, Vincent Drive, Edgbaston, Birmingham, B15 2SQ, UK.
| | - Simon K Delves
- Institute of Naval Medicine, Alverstoke, Hampshire, PO12 2DL, UK
| | | | - Adrian J Allsopp
- Institute of Naval Medicine, Alverstoke, Hampshire, PO12 2DL, UK
| | - Stephen J Brett
- Department of Surgery and Cancer, Imperial College London, Care of General Intensive Care Unit, Hammersmith Hospital Campus, Du Cane Road, London, W12 0HS, UK
| | | | - David R Woods
- Department of Military Medicine, Royal Centre for Defence Medicine, ICT Building, Birmingham Research Park, Vincent Drive, Edgbaston, Birmingham, B15 2SQ, UK.,Carnegie Research Institute, Leeds Beckett University, Leeds, LS6 3QS, UK
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Lamarche DT, Meade RD, D'Souza AW, Flouris AD, Hardcastle SG, Sigal RJ, Boulay P, Kenny GP. The recommended Threshold Limit Values for heat exposure fail to maintain body core temperature within safe limits in older working adults. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2017; 14:703-711. [PMID: 28609164 DOI: 10.1080/15459624.2017.1321844] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
PURPOSE The American Conference of Governmental and Industrial Hygienists (ACGIH®) Threshold Limit Values (TLV® guidelines) for work in the heat consist of work-rest (WR) allocations designed to ensure a stable core temperature that does not exceed 38°C. However, the TLV® guidelines have not been validated in older workers. This is an important shortcoming given that adults as young as 40 years demonstrate impairments in their ability to dissipate heat. We therefore evaluated body temperature responses in older adults during work performed in accordance to the TLV® recommended guidelines. METHODS On three occasions, 9 healthy older (58 ± 5 years) males performed a 120-min work-simulated protocol in accordance with the TLV® guidelines for moderate-to-heavy intensity work (360 W fixed rate of heat production) in different wet-bulb globe temperatures (WBGT). The first was 120 min of continuous (CON) cycling at 28.0°C WBGT (CON[28°C]). The other two protocols were 15-min intermittent work bouts performed with different WR cycles and WBGT: (i) WR of 3:1 at 29.0°C (WR3:1[29°C]) and (ii) WR of 1:1 at 30.0°C (WR1:1[30°C]). Rectal temperature was measured continuously. The rate of change in mean body temperature was determined via thermometry (weighting coefficients: rectal, 0.9; mean skin temperature, 0.1) and direct calorimetry. RESULTS Rectal temperature exceeded 38°C in all participants in CON[28°C] and WR3:1[29°C] whereas a statistically similar proportion of workers exceeded 38°C in WR1:1[30°C] (χ2; P = 0.32). The average time for rectal temperature to reach 38°C was: CON[28°C], 53 ± 7; WR3:1[29°C], 79 ± 11; and WR1:1[30°C], 100 ± 29 min. Finally, while a stable mean body temperature was not achieved in any work condition as measured by thermometry (i.e., >0°C·min-1; all P<0.01), heat balance as determined by direct calorimetry was achieved in WR3:1[29°C] and WR1:1[30°C] (both P ≥ 0.08). CONCLUSION Our findings indicate that the TLV® guidelines do not prevent body core temperature from exceeding 38°C in older workers. Furthermore, a stable core temperature was not achieved within safe limits (i.e., ≤38°C) indicating that the TLV® guidelines may not adequately protect all individuals during work in hot conditions.
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Affiliation(s)
- Dallon T Lamarche
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , Ontario , Canada
| | - Robert D Meade
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , Ontario , Canada
| | - Andrew W D'Souza
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , Ontario , Canada
| | - Andreas D Flouris
- b FAME Laboratory, Department of Exercise Science , University of Thessaly , Trikala , Greece
| | | | - Ronald J Sigal
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , Ontario , Canada
- d Departments of Medicine, Cardiac Sciences and Community Health Sciences, Faculties of Medicine and Kinesiology , University of Calgary , Calgary , Alberta , Canada
- e Clinical Epidemiology Program , Ottawa Hospital Research Institute , Ottawa , Ontario , Canada
| | - Pierre Boulay
- f Faculty of Physical Activity Sciences , University of Sherbrooke , Sherbrooke , Quebec , Canada
| | - Glen P Kenny
- a Human and Environmental Physiology Research Unit, School of Human Kinetics , University of Ottawa , Ottawa , Ontario , Canada
- e Clinical Epidemiology Program , Ottawa Hospital Research Institute , Ottawa , Ontario , Canada
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Direct calorimetry: a brief historical review of its use in the study of human metabolism and thermoregulation. Eur J Appl Physiol 2017; 117:1765-1785. [DOI: 10.1007/s00421-017-3670-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 06/21/2017] [Indexed: 01/08/2023]
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Abstract
In the aftermath of the Paris Agreement, there is a crucial need for scientists in both thermal physiology and climate change research to develop the integrated approaches necessary to evaluate the health, economic, technological, social, and cultural impacts of 1.5°C warming. Our aim was to explore the fidelity of remote temperature measurements for quantitatively identifying the continuous redistribution of heat within both the Earth and the human body. Not accounting for the regional distribution of warming and heat storage patterns can undermine the results of thermal physiology and climate change research. These concepts are discussed herein using two parallel examples: the so-called slowdown of the Earth's surface temperature warming in the period 1998-2013; and the controversial results in thermal physiology, arising from relying heavily on core temperature measurements. In total, the concept of heat is of major importance for the integrity of systems, such as the Earth and human body. At present, our understanding about the interplay of key factors modulating the heat distribution on the surface of the Earth and in the human body remains incomplete. Identifying and accounting for the interconnections among these factors will be instrumental in improving the accuracy of both climate models and health guidelines.
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Affiliation(s)
- Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece; Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
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Kenny GP, McGinn R. Restoration of thermoregulation after exercise. J Appl Physiol (1985) 2016; 122:933-944. [PMID: 27881668 DOI: 10.1152/japplphysiol.00517.2016] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/26/2016] [Accepted: 11/16/2016] [Indexed: 11/22/2022] Open
Abstract
Performing exercise, especially in hot conditions, can heat the body, causing significant increases in internal body temperature. To offset this increase, powerful and highly developed autonomic thermoregulatory responses (i.e., skin blood flow and sweating) are activated to enhance whole body heat loss; a response mediated by temperature-sensitive receptors in both the skin and the internal core regions of the body. Independent of thermal control of heat loss, nonthermal factors can have profound consequences on the body's ability to dissipate heat during exercise. These include the activation of the body's sensory receptors (i.e., baroreceptors, metaboreceptors, mechanoreceptors, etc.) as well as phenotypic factors such as age, sex, acclimation, fitness, and chronic diseases (e.g., diabetes). The influence of these factors extends into recovery such that marked impairments in thermoregulatory function occur, leading to prolonged and sustained elevations in body core temperature. Irrespective of the level of hyperthermia, there is a time-dependent suppression of the body's physiological ability to dissipate heat. This delay in the restoration of postexercise thermoregulation has been associated with disturbances in cardiovascular function which manifest most commonly as postexercise hypotension. This review examines the current knowledge regarding the restoration of thermoregulation postexercise. In addition, the factors that are thought to accelerate or delay the return of body core temperature to resting levels are highlighted with a particular emphasis on strategies to manage heat stress in athletic and/or occupational settings.
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Affiliation(s)
- Glen P Kenny
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Ryan McGinn
- Human and Environmental Physiology Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
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Smith KR, Woodward A, Lemke B, Otto M, Chang CJ, Mance AA, Balmes J, Kjellstrom T. The last Summer Olympics? Climate change, health, and work outdoors. Lancet 2016; 388:642-4. [PMID: 27533426 DOI: 10.1016/s0140-6736(16)31335-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 08/02/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Kirk R Smith
- School of Public Health, University of California, Berkeley, CA, USA.
| | - Alistair Woodward
- School of Population Health, University of Auckland, Auckland, New Zealand
| | - Bruno Lemke
- Nelson Marlborough Institute of Technology, Digital Technology, Nelson, New Zealand
| | - Matthias Otto
- Nelson Marlborough Institute of Technology, Digital Technology, Nelson, New Zealand
| | - Cindy J Chang
- Department of Orthopaedics and Department of Family & Community Medicine, University of California, San Francisco, CA, USA
| | - Anna A Mance
- School of Public Health, University of California, Berkeley, CA, USA
| | - John Balmes
- School of Public Health, University of California, Berkeley, CA, USA
| | - Tord Kjellstrom
- Centre for Technology Research and Innovation, Limassol, Cyprus
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