301
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Auliciems A. Thermal sensation and cell adaptability. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2014; 58:325-35. [PMID: 23756606 PMCID: PMC3955135 DOI: 10.1007/s00484-013-0680-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2012] [Revised: 05/07/2013] [Accepted: 05/08/2013] [Indexed: 06/02/2023]
Abstract
Whole person adaptive comfort is discussed with reference to recent findings in molecular scale systems biology. The observations are upscaled to hypotheses relating to less traditional interpretations of thermal processes, which have new implications for indoor climate management and design. Arguments are presented for a revision of current focus, model and paradigm. The issue is seen as a problem of integrating theoretical development, conceptual modeling and as an investigation of the extent to which environments and acclimatization can be used to achieve individual fitness and health, not only at the subjective comfort level, as hitherto promoted. It is argued that there are many questions yet to be asked about adaptability before celebrating a particular adaptive state.
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Affiliation(s)
- Andris Auliciems
- Faculty Geography & Earth Sciences, University of Latvia, Raiņa Blvd 19, Rīga, 1548, Latvia,
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302
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Plasma and lymphocyte Hsp72 responses to exercise in athletes with prior exertional heat illness. Amino Acids 2014; 46:1491-9. [DOI: 10.1007/s00726-014-1721-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 03/03/2014] [Indexed: 10/25/2022]
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303
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Brunetti ND, Amoruso D, De Gennaro L, Dellegrottaglie G, Di Giuseppe G, Antonelli G, Di Biase M. Hot Spot: Impact of July 2011 Heat Wave in Southern Italy (Apulia) on Cardiovascular Disease Assessed by Emergency Medical Service and Telemedicine Support. Telemed J E Health 2014; 20:272-81. [DOI: 10.1089/tmj.2013.0086] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
| | - Daniele Amoruso
- Unità Operativa Cardiologia, Azienda Ospedaliera Policlinico, Bari, Italy
| | | | | | | | | | - Matteo Di Biase
- Department of Cardiology, University of Foggia, Foggia, Italy
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304
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305
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306
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Stacey M, Woods D, Ross D, Wilson D. Heat illness in military populations: asking the right questions for research. J ROY ARMY MED CORPS 2014; 160:121-4. [PMID: 24389745 DOI: 10.1136/jramc-2013-000204] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Reports of death and injury in military populations due to exertional heat illness (EHI) and its most severe form, exertional heat stroke, date from antiquity. Yet, understanding of why one soldier may succumb to EHI, while those around him do not, is incomplete. This paper sets out research questions in support of the health of military populations who may experience exertional heat stress. The mechanisms by which excess body heat arises and is dissipated are outlined and the significance of core temperature measurement during exercise is discussed. Known risk factors for EHI are highlighted and new approaches for identifying individual vulnerability to EHI are introduced. A better understanding of the underlying pathophysiology may allow the effective use of biomarkers in future risk stratification and identification of EHI, allied to emerging genetic technologies. The thermal burden associated with states of dress and personal protection of Service personnel in their worldwide duties should be a focus of research as new equipment is introduced. At all times, the discerning use of existing guidance by Commanders on the ground will remain a mainstay of preventing EHI.
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Affiliation(s)
- Mike Stacey
- Section of Anaesthetics, Pain Medicine and Intensive Care, Imperial College, London, UK General Intensive Care Unit, Hammersmith Hospital, Greater London, UK
| | - D Woods
- Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
| | - D Ross
- Army Health Unit, Army Medical Directorate, Camberley, UK
| | - D Wilson
- Department of Military Medicine, Royal Centre for Defence Medicine, Birmingham, UK
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307
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Leon LR, Dineen S, Blaha MD, Rodriguez-Fernandez M, Clarke DC. Attenuated thermoregulatory, metabolic, and liver acute phase protein response to heat stroke in TNF receptor knockout mice. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1421-32. [DOI: 10.1152/ajpregu.00127.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tumor necrosis factor (TNF) is considered an adverse mediator of heat stroke (HS) based on clinical studies showing high serum levels. However, soluble TNF receptors (sTNFR; TNF antagonists) were higher in survivors than nonsurvivors, and TNFR knockout (KO) mice showed a trend toward increased mortality, suggesting TNF has protective actions for recovery. We delineated TNF actions in HS by comparing thermoregulatory, metabolic, and inflammatory responses between B6129F2 (wild type, WT) and TNFR KO mice. Before heat exposure, TNFR KO mice showed ∼0.4°C lower core temperature (Tc; radiotelemetry), ∼10% lower metabolic rate (Mr; indirect calorimetry), and reduced plasma interleukin (IL)-1α and sIL-1RI than WT mice. KO mice selected warmer temperatures than WT mice in a gradient but remained hypothermic. In the calorimeter, both genotypes showed a similar heating rate, but TNFR KO maintained lower Tc and Mr than WT mice for a given heat exposure duration and required ∼30 min longer to reach maximum Tc (42.4°C). Plasma IL-6 increased at ∼3 h of recovery in both genotypes, but KO mice showed a more robust sIL-6R response. Higher sIL-6R in the KO mice was associated with delayed liver p-STAT3 protein expression and attenuated serum amyloid A3 (SAA3) gene expression, suggesting the acute phase response (APR) was attenuated in these mice. Our data suggest that the absence of TNF signaling induced a regulated hypothermic state in the KO mice, TNF-IL-1 interactions may modulate Tc and Mr during homeostatic conditions, and TNF modulates the APR during HS recovery through interactions with the liver IL-6-STAT3 pathway of SAA3 regulation.
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Affiliation(s)
- Lisa R. Leon
- Thermal Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Shauna Dineen
- Thermal Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Michael D. Blaha
- Thermal Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Maria Rodriguez-Fernandez
- Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California; and
| | - David C. Clarke
- Department of Biological Engineering and Center for Cellular Decision Processes, Massachusetts Institute of Technology, Cambridge, Massachusetts
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308
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FORTES MATTHEWBENJAMIN, DI FELICE UMBERTO, DOLCI ALBERTO, JUNGLEE NAUSHADA, CROCKFORD MICHAELJ, WEST LIAM, HILLIER-SMITH RYAN, MACDONALD JAMIEHUGO, WALSH NEILPETER. Muscle-Damaging Exercise Increases Heat Strain during Subsequent Exercise Heat Stress. Med Sci Sports Exerc 2013; 45:1915-24. [DOI: 10.1249/mss.0b013e318294b0f8] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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309
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Rodriguez-Fernandez M, Grosman B, Yuraszeck TM, Helwig BG, Leon LR, Doyle III FJ. Modeling the intra- and extracellular cytokine signaling pathway under heat stroke in the liver. PLoS One 2013; 8:e73393. [PMID: 24039931 PMCID: PMC3764238 DOI: 10.1371/journal.pone.0073393] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 07/22/2013] [Indexed: 12/24/2022] Open
Abstract
Heat stroke (HS) is a life-threatening illness induced by prolonged exposure to a hot environment that causes central nervous system abnormalities and severe hyperthermia. Current data suggest that the pathophysiological responses to heat stroke may not only be due to the immediate effects of heat exposure per se but also the result of a systemic inflammatory response syndrome (SIRS). The observation that pro- (e.g., IL-1) and anti-inflammatory (e.g., IL-10) cytokines are elevated concomitantly during recovery suggests a complex network of interactions involved in the manifestation of heat-induced SIRS. In this study, we measured a set of circulating cytokine/soluble cytokine receptor proteins and liver cytokine and receptor mRNA accumulation in wild-type and tumor necrosis factor (TNF) receptor knockout mice to assess the effect of neutralization of TNF signaling on the SIRS following HS. Using a systems approach, we developed a computational model describing dynamic changes (intra- and extracellular events) in the cytokine signaling pathways in response to HS that was fitted to novel genomic (liver mRNA accumulation) and proteomic (circulating cytokines and receptors) data using global optimization. The model allows integration of relevant biological knowledge and formulation of new hypotheses regarding the molecular mechanisms behind the complex etiology of HS that may serve as future therapeutic targets. Moreover, using our unique modeling framework, we explored cytokine signaling pathways with three in silico experiments (e.g. by simulating different heat insult scenarios and responses in cytokine knockout strains in silico).
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Affiliation(s)
- Maria Rodriguez-Fernandez
- Institute for Collaborative Biotechnologies, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, United States of America
| | - Benyamin Grosman
- Institute for Collaborative Biotechnologies, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, United States of America
| | - Theresa M. Yuraszeck
- Institute for Collaborative Biotechnologies, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, United States of America
| | - Bryan G. Helwig
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States of America
| | - Lisa R. Leon
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States of America
| | - Francis J. Doyle III
- Institute for Collaborative Biotechnologies, University of California Santa Barbara, Santa Barbara, California, United States of America
- Department of Chemical Engineering, University of California Santa Barbara, Santa Barbara, United States of America
- * E-mail:
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310
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Moore JP, Harper Smith AD, Di Felice U, Walsh NP. Three nights of sleep deprivation does not alter thermal strain during exercise in the heat. Eur J Appl Physiol 2013; 113:2353-60. [PMID: 23760736 DOI: 10.1007/s00421-013-2671-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 05/29/2013] [Indexed: 11/30/2022]
Abstract
PURPOSE Individuals exposed to total sleep deprivation may experience an increased risk of impaired thermoregulation and physiological strain during prolonged physical activity in the heat. However, little is known of the impact of more relevant partial sleep deprivation (PSD). This randomized counterbalanced study investigated the effect of PSD on thermal strain during an exercise-heat stress. METHODS Ten healthy individuals performed two stress tests (45 min running, 70 % [Formula: see text] 33 °C, 40 % RH). Each trial followed three nights of controlled sleep: normal [479 (SD 2) min sleep night(-1); Norm] and PSD [116 (SD 4) min sleep night(-1)]. Energy balance and hydration state were controlled throughout the trials. Rectal temperatures (T re), mean skin temperature ([Formula: see text]), heart rate (HR), RPE, and thermal sensations (TS) were measured at regular intervals during each heat stress trial. RESULTS There was a significant main effect of time (P < 0.05) for all of these variables. However, no differences (P > 0.05) were observed between PSD and Norm, respectively, for T re [39.0 (0.5) vs. 39.1 (0.5) °C], [Formula: see text], [36.1 (0.6) vs. 36.0 (0.7) °C] and HR [181 (13) vs. 182 (13) beats min(-1))] at the end of exercise-heat stress. There were no differences (P > 0.05) in [Formula: see text], PSI, RPE, TS and whole-body sweat rate between PSD versus Norm. CONCLUSION Since greater physiological strain during exercise-heat stress did not follow three nights of PSD, it appears that sleep loss may have minimal impact upon thermal strain during exercise in the heat, at least as evaluated within this experiment.
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Affiliation(s)
- Jonathan P Moore
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Gwynedd, Bangor, Wales LL57 2PZ, UK.
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311
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Gonzalez RR, Kenefick RW, Muza SR, Hamilton SW, Sawka MN. Sweat rate and prediction validation during high-altitude treks on Mount Kilimanjaro. J Appl Physiol (1985) 2012; 114:436-43. [PMID: 23271696 DOI: 10.1152/japplphysiol.01176.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study measured sweat rates (m(sw)) during high-altitude summer treks on Mt. Kilimanjaro to evaluate the efficacy of a recently developed fuzzy piecewise sweat prediction equation (Pw,sol) for application to high-altitude conditions. We hypothesized that the Pw,sol equation, adjusted for the barometric pressure (Pb) decreasing steadily at high altitude (Pw,sol+Alt), would allow for a more accurate prediction of m(sw) than Pw,sol unadjusted for altitude (Pw,sol(SL)). Fifteen men (43 ± 16 yr; 80 ± 22 kg) and seven women (46 ± 16 yr; 77 ± 18 kg) wearing hiking clothes (clo ∼1.15; clothing evaporative potential = 0.27) and carrying light loads (9 ± 2 kg), were studied during morning and afternoon treks (∼2-3 h) while ascending from 2,829 m to 3,505 m. After each trek, m(sw) was measured with specific biophysical parameters at 15-min intervals. During the trek day, Pb progressively declined (530 to 504 Torr), as solar radiation and ambient temperature (°C) rose transiently. During all treks, m(sw) ranged from 68 to 393 g·m(-2)·h(-1) (0.14 to 0.79 l/h). For each subject, derived Pw,sol(SL) and Pw,sol+Alt model outputs accurately predicted the morning and afternoon average m(sw) within a root mean square error of 0.145 l/h. No differences were found between Pw,sol(SL) and Pw,sol+Alt values. In conclusion, we report the first m(sw) measured during outdoor high-altitude activities and determined that Pw,sol(SL) equation can be used to predict fluid needs during high-altitude activities without alterations for lower Pb. This model prediction provides a valid water planning tool for outdoor activities at high altitude up to 3,500 m.
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Affiliation(s)
- Richard R Gonzalez
- Biology Department, New Mexico State University, Las Cruces, New Mexico, USA
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312
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Sawka MN. Career perspectives of Michael N. Sawka. EXTREME PHYSIOLOGY & MEDICINE 2012; 1:10. [PMID: 23848980 PMCID: PMC3710095 DOI: 10.1186/2046-7648-1-10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 08/23/2012] [Indexed: 11/10/2022]
Abstract
UNLABELLED This invited autobiography reviews the career of Michael N. Sawka. Influences: Dr. Sawka soon will retire after a 40-year research career and was influenced by great professors, mentors and colleagues. Career Path: After working at the Dayton Veterans Administration Medical Center and Wright State University, Dr. Sawka's remaining 32 years were at the US Army Research Institute of Environmental Medicine. Research Story: His primary research thrusts included: 1) physiology of upper body exercise; 2) blood volume and its impact on thermoregulation and performance; 3) hydration and its impact on thermoregulation and performance 4) heat stress physiology - adaptations / maladaptations and performance. SUMMARY His career highlights were the personal interactions, intellectual excitement and satisfaction of producing knowledge that will be "tested by time".
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Affiliation(s)
- Michael N Sawka
- Thermal & Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Kansas Street, Natick, MA 01760-5007, USA.
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313
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Sawka MN, Cheuvront SN, Kenefick RW. High skin temperature and hypohydration impair aerobic performance. Exp Physiol 2011; 97:327-32. [PMID: 22143882 DOI: 10.1113/expphysiol.2011.061002] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This paper reviews the roles of hot skin (>35°C) and body water deficits (>2% body mass; hypohydration) in impairing submaximal aerobic performance. Hot skin is associated with high skin blood flow requirements and hypohydration is associated with reduced cardiac filling, both of which act to reduce aerobic reserve. In euhydrated subjects, hot skin alone (with a modest core temperature elevation) impairs submaximal aerobic performance. Conversely, aerobic performance is sustained with core temperatures >40°C if skin temperatures are cool-warm when euhydrated. No study has demonstrated that high core temperature (∼40°C) alone, without coexisting hot skin, will impair aerobic performance. In hypohydrated subjects, aerobic performance begins to be impaired when skin temperatures exceed 27°C, and even warmer skin exacerbates the aerobic performance impairment (-1.5% for each 1°C skin temperature). We conclude that hot skin (high skin blood flow requirements from narrow skin temperature to core temperature gradients), not high core temperature, is the 'primary' factor impairing aerobic exercise performance when euhydrated and that hypohydration exacerbates this effect.
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Affiliation(s)
- Michael N Sawka
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, 42 Kansas Street, Natick, MA 01760, USA
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