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Notley SR, Akerman AP, Friesen BJ, Poirier MP, McCourt E, Flouris A, Kenny GP. Heat tolerance and the validity of occupational heat exposure limits in women during moderate-intensity work. Appl Physiol Nutr Metab 2022; 47:711-724. [PMID: 35259026 DOI: 10.1139/apnm-2022-0003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To mitigate excessive rises in core temperature (>1°C) in non heat-acclimatized workers, the American Conference of Governmental Industrial Hygienists (ACGIH) provide heat stress limits (Action Limit Values; ALV), defined by the wet-bulb globe temperature (WBGT) and a worker's metabolic rate. However, since these limits are based on data from men, their suitability for women remains unclear. We therefore assessed core temperature and heart rate in men (n=19; body surface area-to-mass ratio: 250 (SD 17) cm2/kg) and women (n=15; body surface area-to-mass ratio: 268 (SD 24) cm2/kg) aged 18-45 years during 180-min walking at a moderate metabolic rate (200 W/m2) in WBGTs below (16 and 24°C) and above (28 and 32°C) ACGIH ALV. Sex did not significantly influence (i) rises in core temperature, irrespective of WBGT, (ii) the proportion of participants with rises in core temperature >1°C in environments below ACGIH limits, and (iii) work duration before rises in core temperature exceeded 1°C or volitional termination in environments above ACGIH limits. Although further studies are needed, these findings indicate that for the purpose of mitigating rises in core temperature exceeding recommended limits (>1°C), ACGIH guidelines have comparable effectiveness in non heat-acclimatized men and women when working at a moderate metabolic rate. Novelty points • Sex did not appreciably influence thermal strain nor the proportion of participants with core temperatures exceeding recommended limits. • Sex did not significantly influence tolerance to uncompensable heat stress • Despite originating from data obtained in only men, current occupational heat stress guidance offered comparable effectiveness in men and women.
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Affiliation(s)
| | | | - Brian J Friesen
- University of Ottawa, Human Kinetics, Ottawa, Ontario, Canada;
| | - Martin P Poirier
- University of Ottawa, School of Human Kinetics, Faculty of Health Sciences, Ottawa, Ontario, Canada;
| | | | - Andreas Flouris
- FAME Laboratory, Institute of Human Performance and Rehabilitation, Centre for Research and Technology Thessaly, Trikala, Thessaly, Greece.,Department of Research and Technology Development, Biomnic Ltd., Trikala, Thessaly, Greece;
| | - Glen P Kenny
- University of Ottawa, 6363, Ottawa, Canada, K1N 6N5.,Ottawa Hospital Research Institute, 10055, Ottawa, Canada, K1Y 4E9;
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Notley SR, Akerman AP, Friesen BJ, Sigal RJ, Flouris AD, Boulay P, Kenny GP. Exercise-heat tolerance in middle-aged-to-older men with type 2 diabetes. Acta Diabetol 2021; 58:809-812. [PMID: 33630133 DOI: 10.1007/s00592-021-01684-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/29/2021] [Indexed: 10/22/2022]
Affiliation(s)
- Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Ashley P Akerman
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, 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
| | - Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, Greece
| | - Pierre Boulay
- Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, 125 University, Room 367, Montpetit Hall, Ottawa, ON, K1N 6N5, Canada.
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada.
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Notley SR, Akerman AP, Friesen BJ, Poirier MP, Sigal RJ, Flouris AD, Boulay P, McCourt E, Ruzicka M, Kenny GP. Heat Tolerance and Occupational Heat Exposure Limits in Older Men with and without Type 2 Diabetes or Hypertension. Med Sci Sports Exerc 2021; 53:2196-2206. [PMID: 33988544 DOI: 10.1249/mss.0000000000002698] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE To mitigate rises in core temperature >1°C, the American Conference of Governmental Industrial Hygienists (ACGIH) recommends upper limits for heat stress (Action Limit Values; ALV), defined by wet-bulb globe temperature (WBGT) and a worker's metabolic rate. However, these limits are based on data from young men and are assumed to be suitable for all workers, irrespective of age or health status. We therefore explored the impact of aging, type 2 diabetes (T2D), and hypertension (HTN), on tolerance to prolonged, moderate-intensity work above and below these limits. METHODS Core temperature and heart rate were assessed in healthy, non-heat acclimatized young (18-30 y, n=13) and older (50-70 y) men (n=14), and non-heat acclimatized older men with T2D (n=10) or HTN (n=13) during moderate-intensity (metabolic rate: 200 W/m2) walking for 180 min (or until termination) in environments above (28 and 32°C WBGT) and below (16 and 24°C WBGT) the ALV for continuous work at this intensity (25°C WBGT). RESULTS Work tolerance in the 32°C WBGT was shorter in men with T2D (median [IQR]; 109 [91, 173] min; p=0.041) and HTN (109 [91, 173] min; p=0.010) compared to healthy older men (180 [133, 180] min). However, aging, T2D, and HTN did not significantly influence (i) core temperature or heart rate reserve, irrespective of WBGT, (ii) the probability that core temperature exceeded recommended limits (>1°C) under the ALV, and (iii) work duration before core temperature exceeded recommended limits (>1°C) above the ALV. CONCLUSION These findings demonstrate that T2D and HTN attenuate tolerance to uncompensable heat stress (32°C WBGT); however, these chronic diseases do not significantly impact thermal and cardiovascular strain, or the validity of ACIGH recommendations during moderate-intensity work.
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Affiliation(s)
- Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada Departments of Medicine, Cardiac Sciences and Community Health Sciences Faculties of Medicine and Kinesiology, University of Calgary, Canada Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada FAME Laboratory, Department of Exercise Science, University of Thessaly, Greece Faculté des sciences de l'activité physique, Université de Sherbrooke, Sherbrooke, Québec, Canada Hypertension Program, Division of Nephrology, University of Ottawa, Ottawa, Canada
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Akerman AP, Notley SR, Sigal RJ, Boulay P, Ruzicka M, Friesen BJ, Kenny GP. Impact of uncomplicated controlled hypertension on thermoregulation during exercise-heat stress. J Hum Hypertens 2020; 35:880-883. [PMID: 33057176 DOI: 10.1038/s41371-020-00402-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 07/29/2020] [Accepted: 08/11/2020] [Indexed: 11/09/2022]
Abstract
Exercise is promoted for management of hypertension and as a general healthy behavior, but environmental conditions are seldom considered in these recommendations. Hypertension may affect skin blood flow and sweating, two of the primary mechanisms which prevent continued elevations in core temperature by facilitating whole-body heat loss during exercise-heat stress. We show that during incremental exercise-heat stress (in hot-dry conditions), controlled and uncomplicated hypertension is unlikely to exert a meaningful effect on whole-body heat loss in individuals who are already physically active.
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Affiliation(s)
- Ashley P Akerman
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Ronald J Sigal
- Department of Medicine, University of Calgary, Calgary, AB, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Marcel Ruzicka
- Division of Nephrology, University of Ottawa, Ottawa, ON, Canada
| | - Brian J Friesen
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, ON, Canada.
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D’Souza AW, Notley SR, Friesen BJ, Mccourt ER, Kenny GP. On the Effect of Sex on Heat Strain During Prolonged Work in the Heat. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Friesen BJ, Notley SR, McCourt E, McCormick JJ, Larocque-Graham A, Boulay P, Kenny GP. Heat Strain in Middle‐aged and Young Men During Prolonged Work in the Heat. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.00741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Poirier MP, Notley SR, Boulay P, Sigal RJ, Friesen BJ, Malcolm J, Flouris AD, Kenny GP. Type 2 diabetes does not exacerbate body heat storage in older adults during brief, extreme passive heat exposure. Temperature (Austin) 2020; 7:263-269. [PMID: 33123619 DOI: 10.1080/23328940.2020.1736760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Aging exacerbates hyperthermia and cardiovascular strain during passive heat exposure, but it remains unclear whether those effects worsen in older adults with type 2 diabetes (T2D). We examined these responses in unacclimatized, physically active, older individuals with (n = 13, mean ± SD age: 60 ± 8 years, HbA1c: 7.0 ± 1.0%) and without (Control, n = 30, 62 ± 6 years) well-controlled T2D during a brief, 3-h passive exposure to extreme heat (44°C, 30% relative humidity). Metabolic heat production, dry heat gain, total heat gain (metabolic heat production + dry heat gain), evaporative heat loss, body heat storage (summation of heat gain/loss), rectal and mean skin temperatures as well as heart rate were measured continuously. No between-group differences were observed for metabolic heat production (T2D vs. Control; 53 ± 5 vs. 55 ± 7 W/m2), dry heat gain (48 ± 9 vs. 47 ± 11 W/m2), total heat gain (101 ± 10 vs. 102 ± 14 W/m2) and evaporative heat loss (83 ± 10 vs. 85 ± 12 W/m2) over the 3 h (all P > 0.05). Consequently, the changes in body heat storage (380 ± 93 vs. 358 ± 172 kJ, P = 0.67) were similar between groups. Moreover, no between-group differences in rectal and mean skin temperatures or heart rate were measured. We conclude that unacclimatized, physically active, older adults with well-controlled T2D do not experience greater hyperthermia and cardiovascular strain compared to their healthy counterparts while resting in extreme heat for a brief, 3-h period.
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Affiliation(s)
- Martin P Poirier
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Pierre Boulay
- Faculté des Sciences de l'activité Physique, Université de Sherbrooke, Sherbrooke, Canada
| | - Ronald J Sigal
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada.,Departments of Medicine, Cardiac Sciences and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Division of Endocrinology and Metabolism, RRDTC, Calgary, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
| | - Janine Malcolm
- Division of Endocrinology and Metabolism, Department of Medicine, University of Ottawa, Ottawa, Canada
| | - Andreas D Flouris
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, Faculty of Health Sciences, University of Ottawa, Ottawa, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Canada
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Gordon K, Blondin DP, Friesen BJ, Tingelstad HC, Kenny GP, Haman F. Seven days of cold acclimation substantially reduces shivering intensity and increases nonshivering thermogenesis in adult humans. J Appl Physiol (1985) 2019; 126:1598-1606. [PMID: 30896355 PMCID: PMC6620656 DOI: 10.1152/japplphysiol.01133.2018] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/21/2019] [Accepted: 03/17/2019] [Indexed: 01/24/2023] Open
Abstract
Daily compensable cold exposure in humans reduces shivering by ~20% without changing total heat production, partly by increasing brown adipose tissue thermogenic capacity and activity. Although acclimation and acclimatization studies have long suggested that daily reductions in core temperature are essential to elicit significant metabolic changes in response to repeated cold exposure, this has never directly been demonstrated. The aim of the present study is to determine whether daily cold-water immersion, resulting in a significant fall in core temperature, can further reduce shivering intensity during mild acute cold exposure. Seven men underwent 1 h of daily cold-water immersion (14°C) for seven consecutive days. Immediately before and following the acclimation protocol, participants underwent a mild cold exposure using a novel skin temperature clamping cold exposure protocol to elicit the same thermogenic rate between trials. Metabolic heat production, shivering intensity, muscle recruitment pattern, and thermal sensation were measured throughout these experimental sessions. Uncompensable cold acclimation reduced total shivering intensity by 36% (P = 0.003), without affecting whole body heat production, double what was previously shown from a 4-wk mild acclimation. This implies that nonshivering thermogenesis increased to supplement the reduction in the thermogenic contribution of shivering. As fuel selection did not change following the 7-day cold acclimation, we suggest that the nonshivering mechanism recruited must rely on a similar fuel mixture to produce this heat. The more significant reductions in shivering intensity compared with a longer mild cold acclimation suggest important differential metabolic responses, resulting from an uncompensable compared with compensable cold acclimation. NEW & NOTEWORTHY Several decades of research have been dedicated to reducing the presence of shivering during cold exposure. The present study aims to determine whether as little as seven consecutive days of cold-water immersion is sufficient to reduce shivering and increase nonshivering thermogenesis. We provide evidence that whole body nonshivering thermogenesis can be increased to offset a reduction in shivering activity to maintain endogenous heat production. This demonstrates that short, but intense cold stimulation can elicit rapid metabolic changes in humans, thereby improving our comfort and ability to perform various motor tasks in the cold. Further research is required to determine the nonshivering processes that are upregulated within this short time period.
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Affiliation(s)
- Kyle Gordon
- Faculty of Health Sciences, University of Ottawa , Ottawa , Canada
| | - Denis P Blondin
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, Ottawa , Canada
| | - Brian J Friesen
- Faculty of Health Sciences, University of Ottawa , Ottawa , Canada
| | | | - Glen P Kenny
- Faculty of Health Sciences, University of Ottawa , Ottawa , Canada
| | - François Haman
- Faculty of Health Sciences, University of Ottawa , Ottawa , Canada
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Flouris AD, Friesen BJ, Herry CL, Seely AJE, Notley SR, Kenny GP. Heart rate variability dynamics during treatment for exertional heat strain when immediate response is not possible. Exp Physiol 2019; 104:845-854. [PMID: 30932277 DOI: 10.1113/ep087297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 03/25/2019] [Indexed: 12/30/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a delay in cold water immersion treatment affect the cardiac autonomic control of exertionally heat-strained individuals? What is the main finding and its importance? Cold water immersion is effective for treating exertionally heat-strained individuals even when treatment is commenced with a significant delay. However, that treatment delay leads to only partial/transient restoration of cardiac autonomic control. Therefore, we recommend that exertional heatstroke patients are continuously monitored for several hours even after core temperature has returned to normal values. ABSTRACT Immediate cold water immersion (CWI) is the gold-standard treatment for exertional heatstroke. In the field, however, treatment is often delayed, primarily owing to a delayed paramedic response and/or inaccurate diagnosis. We examined the effect of treatment (reduction of rectal temperature to 37.5°C) delays of 5 (short), 20 (moderate) and 40 (prolonged) min on cardiac autonomic control [as assessed via heart rate variability (HRV)] in eight exertionally heat-strained (40.0°C rectal temperature) individuals. Eleven HRV indices were computed that have been described commonly in the literature and characterize almost all known domains of the variability and complexity of the cardiopulmonary system. We found that the cardiac autonomic control (as assessed via HRV) of exertionally heat-strained individuals was significantly affected by the amount of time it took for the CWI treatment to be applied. Six out of 11 HRV indices studied, from all variability domains, displayed strong (P ≤ 0.005) time × delay interaction effects. Moreover, the number of significantly (P ≤ 0.005) abnormal (i.e. different from the short delay) HRV indices more than doubled (seven versus 15) from the moderate delay to the prolonged delay. Finally, our results demonstrated that a CWI treatment applied with delays of 20 and, primarily, 40 min did not lead to a full restoration of cardiac autonomic control of exertionally heat-strained individuals. In conclusion, this study supports CWI for treating exertionally heat-strained individuals even when applied with prolonged delay, but it highlights the importance of continued cardiac monitoring of patients who have suffered exertional heatstroke for several hours after restoration of core temperature to normal.
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Affiliation(s)
- Andreas D Flouris
- FAME Laboratory, Department of Physical Education and Sport Science, University of Thessaly, Trikala, 42100, Greece.,Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Brian J Friesen
- Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada
| | - Andrew J E Seely
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada.,Thoracic Surgery and Critical Care Medicine, Ottawa Hospital, Ontario, Canada
| | - Sean R Notley
- Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada
| | - Glen P Kenny
- Human Environmental Physiological Research Unit, University of Ottawa, Ottawa, ON, Canada.,Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ontario, Canada
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Notley SR, Meade RD, D'Souza AW, Friesen BJ, Kenny GP. Heat Loss Is Impaired in Older Men on the Day after Prolonged Work in the Heat. Med Sci Sports Exerc 2018. [PMID: 30113539 DOI: 10.1249/mss.0000000000001643.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Prolonged work in the heat may exacerbate the rise in core temperature on the next work day, especially in older workers who display impairments in whole-body heat loss that increase body heat storage and core temperature relative to young adults during heat stress. We therefore evaluated whether whole-body heat loss in older adults was impaired on the day after prolonged work in the heat. METHODS Whole-body heat exchange and heat storage were assessed in nine older (53-64 yr) men during three 30-min bouts of semirecumbent cycling at fixed rates of metabolic heat production (150 [Ex1], 200 [Ex2], 250 W·m [Ex3]), each separated by 15-min recovery, in hot-dry conditions (40°C, 20% relative humidity), immediately before (day 1), and on the day after (day 2) a prolonged, work simulation (~7.5 h) involving moderate-intensity intermittent exercise in hot-dry conditions (38°C, 34% relative humidity). Total heat loss (evaporative ± dry heat exchange) and metabolic heat production were measured using direct and indirect calorimetry, respectively. Body heat storage was quantified as the temporal summation of heat production and loss. RESULTS Total heat loss (mean ± SD) during Ex1 did not differ between days 1 and 2 (151 ± 15 and 147 ± 14 W·m, respectively; P = 0.27), but was attenuated on day 2 during Ex2 (181 ± 15 W·m) and Ex3 (218 ± 16 W·m) relative to day 1 (192 ± 14 and 230 ± 19 W·m, respectively; both P < 0.01). Consequently, body heat storage throughout the protocol on day 2 (276 ± 114 kJ) was 31% greater than on day 1 (191 ± 87 kJ; P < 0.01). CONCLUSIONS Prolonged work in the heat causes next-day impairments in whole-body heat loss, which exacerbate heat storage and may elevate the risk of heat injury on the following day in older workers.
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Affiliation(s)
- Sean R Notley
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, CANADA
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Notley SR, Meade RD, D’Souza AW, Friesen BJ, Kenny GP. Prolonged Work in the Heat Impairs Heat Loss on the Next day in Older Men. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000537136.76597.99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Poirier MP, Notley SR, Gagnon D, McGinn RR, Friesen BJ, Flouris AD, Kenny GP. Defining Acceptable Cold‐Water Immersion Times for the Treatment of Exertional Hyperthermia When Rectal Temperature Measurements are not Available. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.859.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin P. Poirier
- Human and Environmental Physiology Research UnitSchool of Human KineticsUniversity of OttawaOttawaONCanada
| | - Sean R. Notley
- Human and Environmental Physiology Research UnitSchool of Human KineticsUniversity of OttawaOttawaONCanada
| | - Daniel Gagnon
- Département de Pharmacologie Et Physiologie, Faculté de MédecineUniversité de MontréalMontréalQCCanada
- Cardiovascular Prevention and Rehabilitation CentreMontreal Heart InstituteMontréalQCCanada
| | | | - Brian J. Friesen
- Human and Environmental Physiology Research UnitSchool of Human KineticsUniversity of OttawaOttawaONCanada
| | - Andreas D. Flouris
- FAME LaboratoryDepartment of Exercise ScienceUniversity of ThessalyTrikalaGreece
| | - Glen P. Kenny
- Human and Environmental Physiology Research UnitSchool of Human KineticsUniversity of OttawaOttawaONCanada
- Clinical Epidemiology ProgramOttawa Hospital Research InstituteOttawaONCanada
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Friesen BJ, Poirier MP, Lamarche DT, D'Souza AW, Kim JH, Notley SR, Kenny GP. Postexercise whole-body sweating increases during muscle metaboreceptor activation in young men. Appl Physiol Nutr Metab 2018; 43:423-426. [PMID: 29316406 DOI: 10.1139/apnm-2017-0675] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We assessed the effect of metaboreceptor activation on whole-body evaporative heat loss (WB-EHL) in 12 men (aged 24 ± 4 years) in the early-to-late stages of a 60-min exercise recovery in the heat. Metaboreceptor activation induced by 1-min isometric-handgrip (IHG) exercise followed by 5-min forearm ischemia to trap metabolites increased WB-EHL by 25%-31% and 26%-34% during the ischemic period relative to IHG-only and control (natural recovery only), respectively, throughout recovery. We show that metaboreceptor activation enhances WB-EHL in recovery.
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Affiliation(s)
- Brian J Friesen
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Martin P Poirier
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Dallon T Lamarche
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Andrew W D'Souza
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Jung-Hyun Kim
- b Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Pittsburgh, PA, USA
| | - Sean R Notley
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Glen P Kenny
- a Human and Environmental Physiological Research Unit, Faculty of Health Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
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Friesen BJ, Poirier MP, Lamarche DT, D’Souza AW, Kim JH, Kenny GP. Postexercise Activation of Muscle Metaboreceptors Modulates Whole-Body Evaporative Heat Loss. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000518116.25047.ad] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kenny GP, Poirier MP, Metsios GS, Boulay P, Dervis S, Friesen BJ, Malcolm J, Sigal RJ, Seely AJE, Flouris AD. Hyperthermia and cardiovascular strain during an extreme heat exposure in young versus older adults. Temperature (Austin) 2017; 4:79-88. [PMID: 28349096 PMCID: PMC5356213 DOI: 10.1080/23328940.2016.1230171] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/21/2016] [Accepted: 08/25/2016] [Indexed: 11/21/2022] Open
Abstract
We examined whether older individuals experience greater levels of hyperthermia and cardiovascular strain during an extreme heat exposure compared to young adults. During a 3-hour extreme heat exposure (44°C, 30% relative humidity), we compared body heat storage, core temperature (rectal, visceral) and cardiovascular (heart rate, cardiac output, mean arterial pressure, limb blood flow) responses of young adults (n = 30, 19-28 years) against those of older adults (n = 30, 55-73 years). Direct calorimetry measured whole-body evaporative and dry heat exchange. Body heat storage was calculated as the temporal summation of heat production (indirect calorimetry) and whole-body heat loss (direct calorimetry) over the exposure period. While both groups gained a similar amount of heat in the first hour, the older adults showed an attenuated increase in evaporative heat loss (p < 0.033) in the first 30-min. Thereafter, the older adults were unable to compensate for a greater rate of heat gain (11 ± 1 ; p < 0.05) with a corresponding increase in evaporative heat loss. Older adults stored more heat (358 ± 173 kJ) relative to their younger (202 ± 92 kJ; p < 0.001) counterparts at the end of the exposure leading to greater elevations in rectal (p = 0.043) and visceral (p = 0.05) temperatures, albeit not clinically significant (rise < 0.5°C). Older adults experienced a reduction in calf blood flow (p < 0.01) with heat stress, yet no differences in cardiac output, blood pressure or heart rate. We conclude, in healthy habitually active individuals, despite no clinically observable cardiovascular or temperature changes, older adults experience greater heat gain and decreased limb perfusion in response to 3-hour heat exposure.
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Affiliation(s)
- Glen P. Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Canada
- CONTACT Glen P. Kenny, PhD 125 University Private, Room 367, Montpetit Hall, Ottawa, Ontario K1N 6N5, Canada
| | - Martin P. Poirier
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - George S. Metsios
- Institute of Sport, Faculty of Education Health and Wellbeing, University of Wolverhampton, Walsall, UK
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Canada
| | - Sheila Dervis
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Brian J. Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Janine Malcolm
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Canada
| | - Ronald J. Sigal
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Canada
- Departments of Medicine, Cardiac Sciences and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Canada
| | - Andrew J. E. Seely
- Divisions of Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Canada
| | - Andreas D. Flouris
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Canada
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
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Carrillo AE, Flouris AD, Herry CL, Poirier MP, Boulay P, Dervis S, Friesen BJ, Malcolm J, Sigal RJ, Seely AJE, Kenny GP. Heart rate variability during high heat stress: a comparison between young and older adults with and without Type 2 diabetes. Am J Physiol Regul Integr Comp Physiol 2016; 311:R669-R675. [PMID: 27511279 DOI: 10.1152/ajpregu.00176.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 08/08/2016] [Indexed: 11/22/2022]
Abstract
We examined whether older individuals with and without Type 2 diabetes (T2D) experience differences in heart rate variability (HRV) during a 3-h exposure to high heat stress compared with young adults. Young (Young; n = 22; 23 ± 3 yr) and older individuals with (T2D; n = 11; 59 ± 9 yr) and without (Older; n = 25; 63 ± 5 yr) T2D were exposed to heat stress (44°C, 30% relative humidity) for 3 h. Fifty-five HRV measures were assessed for 15 min at baseline and at minutes 82.5-97.5 (Mid) and minutes 165-180 (End) during heat stress. When compared with Young, a similar number of HRV indices were significantly different (P < 0.05) in Older (Baseline: 35; Mid: 29; End: 32) and T2D (Baseline: 31; Mid: 30; End: 27). In contrast, the number of HRV indices significantly different (P < 0.05) between Older and T2D were far fewer (Baseline: 13, Mid: 1, End: 3). Within-group analyses demonstrated a greater change in the Young group's HRV during heat stress compared with Older and T2D; the number of significantly different (P < 0.05) HRV indices between baseline and End were 42, 29, and 20, for Young, Older, and T2D, respectively. Analysis of specific HRV domains suggest that the Young group experienced greater sympathetic activity during heat stress compared with Older and T2D. In conclusion, when compared with young, older individuals with and without T2D demonstrate low HRV at baseline and less change in HRV (including an attenuated sympathetic response) during 3 h high heat stress, potentially contributing to impaired thermoregulatory function.
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Affiliation(s)
- Andres E Carrillo
- FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece.,Department of Exercise Science, Chatham University, Pittsburgh, Pennsylvania
| | - 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, Ontario, Canada
| | - Christophe L Herry
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Martin P Poirier
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Pierre Boulay
- Faculty of Physical Activity Sciences, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Sheila Dervis
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Janine Malcolm
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Ronald J Sigal
- Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada.,Departments of Medicine, Cardiac Sciences, and Community Health Sciences, Faculties of Medicine and Kinesiology, University of Calgary, Calgary, Alberta, Canada; and
| | - Andrew J E Seely
- Thoracic Surgery and Critical Care Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada; .,Clinical Epidemiology Program, The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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Friesen BJ, Lauzon MA, Blondin DP, Haman F, Poirier MP, Kenny GP. Does the Rate of Heat Storage Define Exercise Intensity Level During Self-paced Exercise at a Fixed Rating of Perceived Exertion? Med Sci Sports Exerc 2016. [DOI: 10.1249/01.mss.0000487423.76265.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lamarche DT, Meade RD, McGinn R, Poirier MP, Friesen BJ, Kenny GP. Temperature of Ingested Water during Exercise Does Not Affect Body Heat Storage. Med Sci Sports Exerc 2016; 47:1272-80. [PMID: 25259541 DOI: 10.1249/mss.0000000000000533] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The objective of this study was to examine the effect of ingested water temperature on heat balance during exercise as assessed by direct calorimetry. METHODS Ten healthy males (25 ± 4 yr) cycled at 50% V˙O2peak (equivalent rate of metabolic heat production (M-W) of 523 ± 84 W) for 75 min under thermocomfortable conditions (25°C, 25% relative humidity) while consuming either hot (50°C) or cold (1.5°C) water. Four 3.2 mL·kg⁻¹ boluses of hot or cold water were consumed 5 min before and at 15, 30, and 45 min after the onset of exercise. Total heat loss (HL = evaporative heat loss (HE) ± dry heat exchange (HD)) and M-W were measured by direct and indirect calorimetry, respectively. Change in body heat content (ΔHb) was calculated as the temporal summation of M-W and HL and adjusted for changes in heat transfer from the ingested fluid (Hfluid). RESULTS The absolute difference for HL (209 ± 81 kJ) was similar to the absolute difference of Hfluid (204 ± 36 kJ) between conditions (P = 0.785). Furthermore, the difference in HL was primarily explained by the corresponding changes in HE (hot: 1538 ± 393 kJ; cold: 1358 ± 330 kJ) because HD was found to be similar between conditions (P = 0.220). Consequently, no difference in ΔHb was observed between the hot (364 ± 152 kJ) and cold (363 ± 134 kJ) conditions (P = 0.971) during exercise. CONCLUSION We show that ingestion of hot water elicits a greater HL relative to cold water ingestion during exercise. However, this response was only compensated for the heat of the ingested fluid as evidenced by similar ΔHb between conditions. Therefore, our findings indicate that relative to cold water ingestion, consuming hot water does not provide a thermoregulatory advantage. Both hot and cold water ingestion results in the same amount of heat stored during prolonged moderate-intensity exercise.
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Affiliation(s)
- Dallon T Lamarche
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, CANADA
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Abstract
PURPOSE We examined the effect of differences in body surface area-to-lean body mass ratio (AD/LBM) on core temperature cooling rates during cold water immersion (CWI, 2°C) and temperate water immersion (TWI, 26°C) after exercise-induced hyperthermia. METHODS Twenty male participants were divided into two groups: high (315.6 ± 7.9 cm·kg, n = 10) and low (275.6 ± 8.6 cm·kg, n = 10) AD/LBM. On two separate occasions, participants ran on a treadmill in the heat (40.0°C, 20% relative humidity) wearing an impermeable rain suit until rectal temperature reached 40.0°C. After exercise, participants were immersed up to the nipples (arms remained out of the water) in either a CWI (2°C) or a TWI (26°C) circulated water bath until rectal temperature returned to 37.5°C. RESULTS Overall rectal cooling rates were significantly different between experimental groups (high vs low AD/LBM, P = 0.005) and between immersion conditions (CWI vs TWI, P < 0.001). Individuals with a high AD/LBM had an approximately 1.7-fold greater overall rectal cooling rate relative to those with low AD/LBM during both CWI (high: 0.27°C·min ± 0.10°C·min vs low: 0.16°C·min ± 0.10°C·min) and TWI (high: 0.10°C·min ± 0.05°C·min vs low: 0.06°C·min ± 0.02°C·min). Further, the overall rectal cooling rates during CWI were approximately 2.7-fold greater than during TWI for both the high (CWI: 0.27°C·min ± 0.10°C·min vs TWI: 0.10°C·min ± 0.05°C·min) and the low (CWI: 0.16°C·min ± 0.10°C·min vs TWI: 0.06°C·min ± 0.02°C·min) AD/LBM groups. CONCLUSION We show that individuals with a low AD/LBM have a reduced rectal cooling rate and take longer to cool than those with a high AD/LBM during both CWI and TWI. However, CWI provides the most effective cooling treatment irrespective of physical differences.
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Affiliation(s)
- Brian J Friesen
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, ON, CANADA
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Lamarche DT, Meade RD, McGinn R, Poirier MP, Friesen BJ, Kenny GP. Response. Med Sci Sports Exerc 2015; 47:1318. [PMID: 25978350 DOI: 10.1249/mss.0000000000000639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Dallon T Lamarche
- Human and Environmental Physiology Research Unit School of Human Kinetics, University of Ottawa Ottawa, ON, CANADA
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Friesen BJ, Poirier MP, Gagnon D, McGinn R, Kenny GP. The Influence of Physical Characteristics in the Treatment of Exertional Hyperthermia by Cold Water Immersion. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477699.78133.d8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kenny GP, Flouris AD, Dervis S, Friesen BJ, Sigal RJ, Malcolm J, Poirier MP. Older Adults Experience Greater Levels of Thermal and Cardiovascular Strain During Extreme Heat Exposures. Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477799.65084.9a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Poirier MP, Friesen BJ, McGinn R, Meade RD, Hardcastle SG, Flouris AD, Kenny GP. Does Fire And Arc-resistant Clothing Influence Whole-body Heat Dissipation During Work In The Heat? Med Sci Sports Exerc 2015. [DOI: 10.1249/01.mss.0000477801.42213.e5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Poirier MP, Meade RD, McGinn R, Friesen BJ, Hardcastle SG, Flouris AD, Kenny GP. The Influence of Arc-Flash and Fire-Resistant Clothing on Thermoregulation during Exercise in the Heat. J Occup Environ Hyg 2015; 12:654-667. [PMID: 25898230 DOI: 10.1080/15459624.2015.1029615] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We evaluated the effect of arc-flash and fire-resistant (AFR) clothing ensembles (CE) on whole-body heat dissipation during work in the heat. On 10 occasions, 7 males performed four 15-min cycling bouts at a fixed rate of metabolic heat production (400 W) in the heat (35°C), each separated by 15-min of recovery. Whole-body heat loss and metabolic heat production were measured by direct and indirect calorimetry, respectively. Body heat storage was calculated as the temporal summation of heat production and heat loss. Responses were compared in a semi-nude state and while wearing two CE styles: (1) single-piece (coveralls) and (2) two-piece (workpant + long-sleeve shirt). For group 1, there was one non-AFR single-piece CE (CE1STD) and three single-piece CE with AFR properties (CE2AFR, CE3AFR, CE4AFR). For group 2, there was one non-AFR two-piece CE (CE5STD) and four two-piece CE with AFR properties (CE6AFR, CE7AFR, CE8AFR, CE9AFR). The workpants for CE6AFR were not AFR-rated, while a cotton undershirt was also worn for conditions CE8AFR and CE9AFR and for all single-piece CE. Heat storage for all conditions (CE1STD: 328 ± 55, CE2AFR: 335 ± 87, CE3AFR: 309 ± 95, CE4AFR: 403 ± 104, CE5STD: 253 ± 78, CE6AFR: 268 ± 89, CE7AFR: 302 ± 70, CE8AFR: 360 ± 36, CE9AFR: 381 ± 99 kJ) was greater than the semi-nude state (160 ± 124 kJ) (all p ≤ 0.05). No differences were measured between single-piece uniforms (p = 0.273). Among the two-piece uniforms, heat storage was greater for CE8AFR and CE9AFR relative to CE5STD and CE6AFR (all p ≤ 0.05), but not CE7AFR (both p > 0.05). Differences between clothing styles were measured such that greater heat storage was observed in both CE1STD and CE2-4AFR relative to CE5STD. Further, heat storage was greater in CE2AFR and CE4AFR relative to CE6AFR, while it was greater in CE4AFR compared to CE7AFR. Body heat storage during work in the heat was not influenced by the use of AFR fabrics in the single- or two-piece uniforms albeit less heat was stored in the two-piece uniforms when no undershirt was worn. However, heat storage was comparable between clothing styles when an undershirt was worn with the two-piece uniform.
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Affiliation(s)
- Martin P Poirier
- a Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa , Ottawa , Ontario , Canada
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Poirier MP, Friesen BJ, Hardcastle SG, Kenny GP. Local Sweat Rates do not Accurately Represent Whole-Body Evaporative Heat Loss following 14-day Dry-Heat Acclimation. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000494119.59966.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Friesen BJ, Poirier MP, Hardcastle SG, Kenny GP. The Influence of Fire and Arc-Resistant Clothing on Heat Dissipation During Work in the Heat. Med Sci Sports Exerc 2014. [DOI: 10.1249/01.mss.0000496299.80492.e0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Poirier M, Friesen BJ, Hardcastle SG, Kenny GP. The effect of progressive heat acclimation on change in body heat content in young males. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1201.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wright HE, McLellan TM, Friesen BJ, Casa DJ, Kenny GP. Influence of circulating cytokines on prolactin during slow vs. fast exertional heat stress followed by active or passive recovery. J Appl Physiol (1985) 2012; 113:574-83. [PMID: 22723625 DOI: 10.1152/japplphysiol.00523.2012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Prolactin (PRL) has been suggested as an indicator of fatigue during exertional heat stress (EHS), given its strong relationship with body core temperature (T(c)); however, the strength of this relationship during different rates of T(c) increase and subsequent recovery is unknown. In addition, given the influence that systemic cytokines, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α, have on the pituitary gland, it would be of interest to determine the relationship between PRL, IL-6, and TNF-α during EHS. The purpose was to examine the PRL, IL-6, and TNF-α heat stress responses during slow and fast heating and subsequent resting or cold water immersion recovery. On 4 days, nine individuals walked at ≈ 45% (slow heating) or ran at ≈ 65% (fast heating) maximal oxygen consumption on a treadmill in the heat (40°C, 30% relative humidity) until rectal temperature (T(re)) reached 39.5°C (esophageal temperature; fast = 39.41 ± 0.04°C, slow = 39.82 ± 0.09°C). Post-EHS, subjects were either immersed in 2°C water or rested seated until T(re) returned to 38.0°C. Venous blood, analyzed for PRL, IL-6, and TNF-α, was obtained at rest, during exercise (T(re) 38.0, 39.0, 39.5°C), the start of recovery (≈ 5 min after 39.5°C), and subsequent recovery (T(re) 39.0, 38.0°C). IL-6 exhibited myokine properties, given the greater increases with slow heating and lack of increase in TNF-α. A strong temperature-dependent PRL response during slow and fast heating provides additional support for the use of PRL as a peripheral marker of impending fatigue, which is independent of IL-6 and TNF-α cytokine responses.
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Affiliation(s)
- Heather E Wright
- Faculty of Health Sciences, Human and Environmental Physiology Research Unit, University of Ottawa, Ottawa, Ontario, Canada
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Kenny GP, Wright HE, Friesen BJ, Casa DJ. Influence Of Slow Versus Fast Ramp Exercise-induced Hyperthermia On Core Cooling Rates During Ice-water Immersion. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000401893.84815.8d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wright HE, Friesen BJ, Kenny GP. Influence Of Slow Versus Fast Increases In Core Temperature On Prolactin And TNF-alpha. Med Sci Sports Exerc 2011. [DOI: 10.1249/01.mss.0000403048.41432.a6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kenny GP, Wright HE, Friesen BJ. Postexercise thermal and cardiovascular responses following fast and slow heating exercise protocols. FASEB J 2011. [DOI: 10.1096/fasebj.25.1_supplement.1053.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Glen P Kenny
- School of Human KineticsUniversity of OttawaOttawaONCanada
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Abstract
Efforts to move the system of care for children with serious emotional disorders toward community-based alternatives has prompted a growing recognition of the need for supportive services for families. This article examines the shifts in policy and administrative practice that are needed in order to move toward a family-centered system of care. Proactive administrative support is particularly important in this system shift. Four important barriers to a family-centered system of care are examined: (1) efforts have tended to focus on the child as the unit of services, rather than on the family; (2) efforts have tended to focus primarily on mental health services, rather than considering the full range of services needed by the child and family; (3) efforts have tended to emphasize formal services, often ignoring the support provided by informal networks; and (4) the resources and expertise of parents and other family members have not been used. New roles for parents--which involve working with administrators and researchers are discussed.
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Abstract
This study involving more than 800 parents whose children have emotional disorders focuses on comparisons between parents who are members of support groups and those who are not. While no difference was found between members and non-members on most demographic variables, members reported needing and using more information and services and found each more difficult to locate than non-members. Thirty-one percent of all respondents identified involvement with other parents as the most helpful activity in coping with their child's problems.
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Affiliation(s)
- N M Koroloff
- Research and Training Center on Family Support and Children's Mental Health, Portland State University, OR 97207-0751
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Friesen BJ, Griesbach J, Jacobs JH, Katz-Leavy J, Olson D. Caring for severely emotionally disturbed children and youth. Improving services for families. Child Today 1988; 17:18-22. [PMID: 3168600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Kruzich JM, Friesen BJ. Blending administrative and community organization practice: the case of community residential facilities. Adm Soc Work 1984; 8:55-66. [PMID: 10310930 DOI: 10.1300/j147v08n04_05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The authors discuss the management of community programs serving deinstitutionalized populations. They make a case for the concept of "community integration" (re-entry into society), arguing that translating the concept into meaningful practice requires clearer specification of the relevant client communities and calls for a blending of traditional administrative and community organizations skills, with resultant implications for social work education. Illustrations are drawn from the field of mental health and the needs of the chronically mentally ill.
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