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Vorländer D, Schultz G, Hoffmann K, Rasch D, Dohnt K. PETR: A novel peristaltic mixed tubular bioreactor simulating human colonic conditions. Biotechnol Bioeng 2024; 121:1118-1143. [PMID: 38151924 DOI: 10.1002/bit.28636] [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: 07/07/2023] [Revised: 12/08/2023] [Accepted: 12/09/2023] [Indexed: 12/29/2023]
Abstract
A novel bioreactor simulating human colonic conditions for in vitro cultivation of intestinal microbiota is presented. The PEristaltic mixed Tubular bioReactor (PETR) is modular designed and periodically kneaded to simulate intestinal peristalsis. The reactor is introduced, characterized from a bioprocess engineer's perspective and discussed in its ability to mimic colon conditions. PETR provides physiological temperature and appropriate anaerobic conditions, simulates intestinal peristalsis, and has a mean residence time of 32.8 ± 0.8 h comparable to the adult human colon. The single-tube design enables a time-constant and longitudinally progressive pH gradient from 5.5 to 7.0. Using a dialysis liquid containing high molecular weight polyethylene glycol, the integrated dialysis system efficiently absorbs short chain fatty acids (up to 60%) and water (on average 850 mL d-1 ). Cultivation of a typical gut bacterium (Bifidobacterium animalis) was performed to demonstrate the applicability for controlled microbiota cultivation. PETR is unique in combining simulation of the entire colon, peristaltic mixing, dialytic water and metabolite absorption, and a progressive pH gradient in a single-tube design. PETR is a further step to precise replication of colonic conditions in vitro for reliable and reproducible microbiota research, such as studying the effect of food compounds, prebiotics or probiotics, or the development and treatment of infections with enteric pathogens, but also for further medical applications such as drug delivery studies or to study the effect of drugs on and their degradation by the microbiota.
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Affiliation(s)
- David Vorländer
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Gábor Schultz
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Kristin Hoffmann
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Detlev Rasch
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
| | - Katrin Dohnt
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Braunschweig Integrated Centre of Systems Biology (BRICS), Technische Universität Braunschweig, Braunschweig, Germany
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 2: physiological measurements. Eur J Appl Physiol 2023; 123:2587-2685. [PMID: 37796291 DOI: 10.1007/s00421-023-05284-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 07/14/2023] [Indexed: 10/06/2023]
Abstract
In this, the second of four historical reviews on human thermoregulation during exercise, we examine the research techniques developed by our forebears. We emphasise calorimetry and thermometry, and measurements of vasomotor and sudomotor function. Since its first human use (1899), direct calorimetry has provided the foundation for modern respirometric methods for quantifying metabolic rate, and remains the most precise index of whole-body heat exchange and storage. Its alternative, biophysical modelling, relies upon many, often dubious assumptions. Thermometry, used for >300 y to assess deep-body temperatures, provides only an instantaneous snapshot of the thermal status of tissues in contact with any thermometer. Seemingly unbeknownst to some, thermal time delays at some surrogate sites preclude valid measurements during non-steady state conditions. To assess cutaneous blood flow, immersion plethysmography was introduced (1875), followed by strain-gauge plethysmography (1949) and then laser-Doppler velocimetry (1964). Those techniques allow only local flow measurements, which may not reflect whole-body blood flows. Sudomotor function has been estimated from body-mass losses since the 1600s, but using mass losses to assess evaporation rates requires precise measures of non-evaporated sweat, which are rarely obtained. Hygrometric methods provide data for local sweat rates, but not local evaporation rates, and most local sweat rates cannot be extrapolated to reflect whole-body sweating. The objective of these methodological overviews and critiques is to provide a deeper understanding of how modern measurement techniques were developed, their underlying assumptions, and the strengths and weaknesses of the measurements used for humans exercising and working in thermally challenging conditions.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- College of Human Ecology, Research Institute of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Martins Januário W, Prata ERBDA, Natali AJ, Prímola-Gomes TN. Normal gastrointestinal temperature values measured through ingestible capsules technology: a systematic review. J Med Eng Technol 2023; 47:389-395. [PMID: 38780358 DOI: 10.1080/03091902.2024.2354793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024]
Abstract
Climate change has amplified the importance of continuous and precise body core temperature (Tcore) monitoring in the everyday life. In this context, assessing Tcore through ingestible capsules technology, i.e., gastrointestinal temperature (Tgastrointestinal), emerges as a good alternative to prevent heat-related illness. Therefore, we conducted a systematic review to point out values of normal Tgastrointestinal measured through ingestible capsules in healthy humans. The study followed PRISMA guidelines and searched the PubMed and Scielo databases from 1971 to 2023. Our search strategy included the descriptors ("gastrointestinal temperature") AND ("measurement"), and eligible studies had to be written in English and measured Tgastrointestinal using ingestible capsules or sensors in healthy adults aged 18-59 at rest. Two pairs of researchers independently reviewed titles and abstracts and identified 35 relevant articles out of 1,088 in the initial search. An average value of 37.13 °C with a standard deviation of 0.24 °C was observed, independently of the gender. The values measured ranged from 36.70 °C to 37.69 °C. In conclusion, this systematic review pointed out the mean value of 37.13 ± 0.24 °C measured by ingestible capsules as reference for resting Tgastrointestinal in healthy adult individuals.
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Affiliation(s)
- William Martins Januário
- Departamento de Educação Física, Laboratório de Performance Humana, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
| | | | - Antônio José Natali
- Departamento de Educação Física, Laboratório de Biologia do Exercício, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
| | - Thales Nicolau Prímola-Gomes
- Departamento de Educação Física, Laboratório de Performance Humana, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brasil
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The In Vitro Efficacy of Activated Charcoal in Fecal Ceftriaxone Adsorption among Patients Who Received Intravenous Ceftriaxone. Antibiotics (Basel) 2023; 12:antibiotics12010127. [PMID: 36671328 PMCID: PMC9854876 DOI: 10.3390/antibiotics12010127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/04/2023] [Accepted: 01/06/2023] [Indexed: 01/11/2023] Open
Abstract
Broad-spectrum antibiotics can kill both pathogens and gut microbiota. Reducing exposure to excess intestinal antibiotics could theoretically protect gut microbiota homeostasis. Recently, engineered charcoals, gel microparticles, and resin beads have demonstrated efficacy in intestinal antibiotic adsorption in animal studies. We report the first in vitro study evaluating human fecal antibiotic adsorption efficacy of conventional activated charcoal (AC). We collected fecal samples from eight patients who received intravenous (IV) ceftriaxone after admission to King Chulalongkorn Memorial Hospital, Thailand, during January−March 2020. Fecal ceftriaxone was measured by indirect competitive enzyme-linked immunoassays. Three different doses of AC were mixed with fecal samples under a specified protocol. The geometric mean reduction in fecal ceftriaxone concentration when mixed with AC 30 mg/g feces was 0.53 (95% CI 0.33−0.85, p-value < 0.001), meaning 47% adsorption efficacy. Increased adsorption was found with higher doses, 71% and 87% for AC 150 and 500 mg/g feces, respectively. In conclusion, the usual food-poisoning-care dose of conventional AC, 30 mg/g feces, demonstrated dose-dependent and significant fecal ceftriaxone adsorption. Conventional oral AC might be a pragmatic and inexpensive option for the protection of gut microbiota in patients receiving IV ceftriaxone. However, in vivo studies and microbiome analysis are needed for further evidence.
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Cramer MN, Gagnon D, Laitano O, Crandall CG. Human temperature regulation under heat stress in health, disease, and injury. Physiol Rev 2022; 102:1907-1989. [PMID: 35679471 PMCID: PMC9394784 DOI: 10.1152/physrev.00047.2021] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 05/10/2022] [Accepted: 05/28/2022] [Indexed: 12/30/2022] Open
Abstract
The human body constantly exchanges heat with the environment. Temperature regulation is a homeostatic feedback control system that ensures deep body temperature is maintained within narrow limits despite wide variations in environmental conditions and activity-related elevations in metabolic heat production. Extensive research has been performed to study the physiological regulation of deep body temperature. This review focuses on healthy and disordered human temperature regulation during heat stress. Central to this discussion is the notion that various morphological features, intrinsic factors, diseases, and injuries independently and interactively influence deep body temperature during exercise and/or exposure to hot ambient temperatures. The first sections review fundamental aspects of the human heat stress response, including the biophysical principles governing heat balance and the autonomic control of heat loss thermoeffectors. Next, we discuss the effects of different intrinsic factors (morphology, heat adaptation, biological sex, and age), diseases (neurological, cardiovascular, metabolic, and genetic), and injuries (spinal cord injury, deep burns, and heat stroke), with emphasis on the mechanisms by which these factors enhance or disturb the regulation of deep body temperature during heat stress. We conclude with key unanswered questions in this field of research.
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Affiliation(s)
- Matthew N Cramer
- Defence Research and Development Canada-Toronto Research Centre, Toronto, Ontario, Canada
| | - Daniel Gagnon
- Montreal Heart Institute and School of Kinesiology and Exercise Science, Université de Montréal, Montréal, Quebec, Canada
| | - Orlando Laitano
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas and University of Texas Southwestern Medical Center, Dallas, Texas
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Hess HW, Stooks JJ, Baker TB, Chapman CL, Johnson BD, Pryor RR, Basile DP, Monroe JC, Hostler D, Schlader ZJ. Kidney injury risk during prolonged exposure to current and projected wet bulb temperatures occurring during extreme heat events in healthy young men. J Appl Physiol (1985) 2022; 133:27-40. [PMID: 35616302 PMCID: PMC9236880 DOI: 10.1152/japplphysiol.00601.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 11/22/2022] Open
Abstract
Wet bulb temperatures (Twet) during extreme heat events are commonly 31°C. Recent predictions indicate that Twet will approach or exceed 34°C. Epidemiological data indicate that exposure to extreme heat events increases kidney injury risk. We tested the hypothesis that kidney injury risk is elevated to a greater extent during prolonged exposure to Twet = 34°C compared with Twet = 31°C. Fifteen healthy men rested for 8 h in Twet = 31 (0)°C and Twet = 34 (0)°C. Insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor of metalloproteinase 2 (TIMP-2), and thioredoxin 1 (TRX-1) were measured from urine samples. The primary outcome was the product of IGFBP7 and TIMP-2 ([IGFBP7·TIMP-2]), which provided an index of kidney injury risk. Plasma interleukin-17a (IL-17a) was also measured. Data are presented at preexposure and after 8 h of exposure and as mean (SD) change from preexposure. The increase in [IGFBP7·TIMP-2] was markedly greater at 8 h in the 34°C [+26.9 (27.1) (ng/mL)2/1,000) compared with the 31°C [+6.2 (6.5) (ng/mL)2/1,000] trial (P < 0.01). Urine TRX-1, a marker of renal oxidative stress, was higher at 8 h in the 34°C [+77.6 (47.5) ng/min] compared with the 31°C [+16.2 (25.1) ng/min] trial (P < 0.01). Plasma IL-17a, an inflammatory marker, was elevated at 8 h in the 34°C [+199.3 (90.0) fg/dL; P < 0.01] compared with the 31°C [+9.0 (95.7) fg/dL] trial. Kidney injury risk is exacerbated during prolonged resting exposures to Twet experienced during future extreme heat events (34°C) compared with that experienced currently (31°C), likely because of oxidative stress and inflammatory processes.NEW AND NOTEWORTHY We have demonstrated that kidney injury risk is increased when men are exposed over an 8-h period to a wet bulb temperature of 31°C and exacerbated at a wet bulb temperature of 34°C. Importantly, these heat stress conditions parallel those that are encountered during current (31°C) and future (34°C) extreme heat events. The kidney injury biomarker analyses indicate both the proximal and distal tubules as the locations of potential renal injury and that the injury is likely due to oxidative stress and inflammation.
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Affiliation(s)
- Hayden W Hess
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Jocelyn J Stooks
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Tyler B Baker
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | | | - Blair D Johnson
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Riana R Pryor
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - David P Basile
- School of Medicine, Indiana University, Indianapolis, Indiana
| | - Jacob C Monroe
- School of Medicine, Indiana University, Indianapolis, Indiana
| | - David Hostler
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Zachary J Schlader
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
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Wilson TE, Narra S, Metzler-Wilson K, Schneider A, Bullens KA, Holt IS. Role of Bradykinin Type 2 Receptors in Human Sweat Secretion: Translational Evidence Does Not Support a Functional Relationship. Skin Pharmacol Physiol 2021; 34:162-166. [PMID: 33794540 DOI: 10.1159/000514497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 01/14/2021] [Indexed: 11/19/2022]
Abstract
Bradykinin increases skin blood flow via a cGMP mechanism but its role in sweating in vivo is unclear. There is a current need to translate cell culture and nonhuman paw pad studies into in vivo human preparations to test for therapeutic viability for disorders affecting sweat glands. Protocol 1: physiological sweating was induced in 10 healthy subjects via perfusing warm (46-48°C) water through a tube-lined suit while bradykinin type 2 receptor (B2R) antagonist (HOE-140; 40 μM) and only the vehicle (lactated Ringer's) were perfused intradermally via microdialysis. Heat stress increased sweat rate (HOE-140 = +0.79 ± 0.12 and vehicle = +0.64 ± 0.10 mg/cm2/min), but no differences were noted with B2R antagonism. Protocol 2: pharmacological sweating was induced in 6 healthy subjects via intradermally perfusing pilocarpine (1.67 mg/mL) followed by the same B2R antagonist approach. Pilocarpine increased sweating (HOE-140 = +0.38 ± 0.16 and vehicle = +0.32 ± 0.12 mg/cm2/min); again no differences were observed with B2R antagonism. Last, 5 additional subjects were recruited for various control experiments which identified that a functional dose of HOE-140 was utilized and it was not sudorific during normothermic conditions. These data indicate B2R antagonists do not modulate physiologically or pharmacologically induced eccrine secretion volumes. Thus, B2R agonist/antagonist development as a potential therapeutic target for hypo- and hyperhidrosis appears unwarranted.
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Affiliation(s)
- Thad E Wilson
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, Indiana, USA.,Department of Physiology, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Seetharam Narra
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, Indiana, USA
| | - Kristen Metzler-Wilson
- Department of Physical Therapy, Indiana University, Indianapolis, Indiana, USA.,Department of Anatomy, Cell Biology, & Physiology, Indiana University, Indianapolis, Indiana, USA.,Department of Dermatology, Indiana University, Indianapolis, Indiana, USA
| | - Artur Schneider
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, Indiana, USA
| | - Kelsey A Bullens
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, Indiana, USA
| | - Ian S Holt
- Division of Biomedical Sciences, Marian University College of Osteopathic Medicine, Indianapolis, Indiana, USA
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Schlader ZJ, Johnson BD, Pryor RR, Stooks J, Clemency BM, Hostler D. Human thermoregulation during prolonged exposure to warm and extremely humid environments expected to occur in disabled submarine scenarios. Am J Physiol Regul Integr Comp Physiol 2020; 318:R950-R960. [PMID: 32233779 PMCID: PMC7272764 DOI: 10.1152/ajpregu.00018.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/17/2020] [Accepted: 03/25/2020] [Indexed: 01/22/2023]
Abstract
Military and civilian emergency situations often involve prolonged exposures to warm and very humid environments. We tested the hypothesis that increases in core temperature and body fluid losses during prolonged exposure to warm and very humid environments are dependent on dry bulb temperature. On three occasions, 15 healthy males (23 ± 3 yr) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C, or 35.0 ± 0.1°C and 95 ± 2% relative humidity normobaric environments for 8 h. Core temperature (telemetry pill) and percent change in body weight, an index of changes in total body water occurring secondary to sweat loss, were measured every hour. Linear regression models were fit to core temperature (over the final 4 h) and percent changes in body weight (over the entire 8 h) for each subject. These equations were used to predict core temperature and percent changes in body weight for up to 24 h. At the end of the 8-h exposure, core temperature was higher in 35°C (38.2 ± 0.4°C, P < 0.01) compared with 32°C (37.2 ± 0.2°C) and 33°C (37.5 ± 0.2°C). At this time, percent changes in body weight were greater in 35°C (-1.9 ± 0.5%) compared with 32°C (-1.4 ± 0.3%, P < 0.01) but not 33°C (-1.6 ± 0.6%, P = 0.17). At 24 h, predicted core temperature was higher in 35°C (39.2 ± 1.4°C, P < 0.01) compared with 32°C (37.6 ± 0.9°C) and 33°C (37.5 ± 0.9°C), and predicted percent changes in body weight were greater in 35°C (-6.1 ± 2.4%) compared with 32°C (-4.6 ± 1.5%, P = 0.04) but not 33°C (-5.3 ± 2.0%, P = 0.43). Prolonged exposure to 35°C, but not 32°C or 33°C, dry bulb temperatures and high humidity is uncompensable heat stress, which exacerbates body fluid losses.
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Affiliation(s)
- Zachary J Schlader
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York
- Department of Kinesiology, School of Public Health, Indiana University, Bloomington, Indiana
| | - Blair D Johnson
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York
| | - Riana R Pryor
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York
| | - Jocelyn Stooks
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York
| | - Brian M Clemency
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York
- Department of Emergency Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - David Hostler
- Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York
- Department of Emergency Medicine, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
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Jones H, Bailey TG, Barr DA, France M, Lucas RAI, Crandall CG, Low DA. Is core temperature the trigger of a menopausal hot flush? Menopause 2019; 26:1016-1023. [PMID: 31453964 DOI: 10.1097/gme.0000000000001357] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Menopausal hot flushes negatively impact quality of life and may be a biomarker of cardiovascular and metabolic disease risk; therefore understanding the physiology of hot flushes is important. Current thinking is that a small elevation (∼0.03-0.05C) in core temperature surpasses a sweating threshold (that is reduced in the menopause), sweating is activated, and a hot flush ensues. Nevertheless, more recent studies examining thermoregulatory control question whether core temperature per se can explain the trigger for a hot flush. The primary aim of this study was to assess the contribution of increases in core temperature on the occurrence of menopausal hot flushes. METHODS For this purpose, 108 hot flushes were objectively assessed in a laboratory setting in 72 symptomatic postmenopausal women (aged 45.8 ± 5.1 years; body mass index 25.9 ± 4.5 kg/m) from five previously reported studies. Women rested, wearing a tube-lined suit (or trousers), which was perfused with 34C water. A subset then underwent mild heat stress (48°C water). Sweat rate, skin blood flow, blood pressure, heart rate, skin, and core temperature were measured continuously throughout. A hot flush was objectively identified during rest (spontaneous hot flush) or mild heating as an abrupt increase in sternal sweat rate. Further, a subset of symptomatic postmenopausal women (n = 22) underwent whole-body passive heating for 60 minutes to identify core temperature thresholds and sensitivities for sweat rate and cutaneous vasodilation, which were compared to a subset of premenopausal women (n = 18). Data were analyzed using t tests and/or general linear modeling, and are presented as mean (95% confidence interval). RESULTS In the 20 minutes before a spontaneous hot flush, core temperature increased by 0.03 ± 0.12C (P < 0.05), but only 51% of hot flushes were preceded by an increase in core temperature. During mild heating, 76% of hot flushes were preceded by an increase in core temperature. The temperature thresholds for sweating were similar, but the vasodilatory threshold was higher in postmenopausal compared with premenopausal women (37.1 ± 0.2 vs 36.8 ± 0.3°C; P = 0.06). CONCLUSION We provide new evidence that menopausal hot flushes are unlikely triggered by an increase in core temperature. These findings provide important information about the physiology of hot flushes that have implications for treatment and management options for menopausal hot flushes.
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Affiliation(s)
- Helen Jones
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, England
| | - Tom G Bailey
- Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Australia
| | - David A Barr
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, England
| | - Madeleine France
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, England
| | - Rebekah A I Lucas
- School of Sport, Exercise and Rehabilitative Sciences, University of Birmingham, Birmingham, UK
| | - Craig G Crandall
- Department of Internal Medicine, University of Texas Southwestern and Texas Health Presbyterian Hospital Dallas, TX
| | - David A Low
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, England
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10
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Schlader ZJ, Okada Y, Best SA, Fu Q, Crandall CG. Arterial stiffness during whole-body passive heat stress in healthy older adults. Physiol Rep 2019; 7:e14094. [PMID: 31062476 PMCID: PMC6503298 DOI: 10.14814/phy2.14094] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 04/23/2019] [Indexed: 12/19/2022] Open
Abstract
We tested the hypothesis that whole-body passive heat stress reduces arterial stiffness in older adults. At preheat stress (baseline) and when core temperature was elevated by 0.6 ± 0.2°C (mild) and 1.2 ± 0.3°C (moderate), arterial stiffness was measured in eight healthy younger (26 ± 5 years) and eight healthy older (70 ± 4 years) adults in the supine position. Arterial stiffness was estimated from carotid-to-femoral pulse wave velocity (cfPWV, applanation tonometry). cfPWV was higher at baseline in older adults (8.8 ± 2.3 m/sec vs. 5.6 ± 0.9 m/sec, P < 0.01) and this difference was maintained throughout passive heat stress (P < 0.01). cfPWV did not change (P ≥ 0.49) with passive heat stress in either younger (at moderate heat stress: 6.0 ± 1.0 m/sec) or older (at moderate heat stress: 8.5 ± 1.6 m/sec) adults. However, the influence of baseline cfPWV on the change in cfPWV during mild (r = -0.66, P = 0.04) and moderate (r = -0.87, P < 0.01) heat stress were inversely related in older adults, and the strength of these relations was not statistically different (P = 0.08). In younger adults, the influence of baseline cfPWV on the change in cfPWV during mild heat stress was also inversely related (r = -0.79, P = 0.01), while the strength of this relation was attenuated at moderate heat stress (r = -0.24, P = 0.30). Changes in arterial stiffness during passive heat stress in adults aged ≥65 year are likely dependent on the magnitude of baseline arterial stiffness and not necessarily age.
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Affiliation(s)
- Zachary J. Schlader
- Center for Research and Education in Special EnvironmentsDepartment of Exercise and Nutrition SciencesUniversity at BuffaloBuffaloNew York
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Yoshiyuki Okada
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasUniversity of Texas Southwestern Medical CenterDallasTexas
- Department of Special Care DentistryHiroshima UniversityHiroshimaJapan
| | - Stuart A. Best
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasUniversity of Texas Southwestern Medical CenterDallasTexas
- Department of Kinesiology and Health PromotionUniversity of KentuckyLexingtonKentucky
| | - Qi Fu
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasUniversity of Texas Southwestern Medical CenterDallasTexas
| | - Craig G. Crandall
- Institute for Exercise and Environmental MedicineTexas Health Presbyterian Hospital DallasUniversity of Texas Southwestern Medical CenterDallasTexas
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11
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The motivation to behaviorally thermoregulate during passive heat exposure in humans is dependent on the magnitude of increases in skin temperature. Physiol Behav 2018; 194:545-551. [PMID: 30017641 DOI: 10.1016/j.physbeh.2018.07.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/19/2018] [Accepted: 07/10/2018] [Indexed: 12/21/2022]
Abstract
We tested the hypothesis that the motivation to behaviorally thermoregulate in humans is dependent on the magnitude of changes in mean skin temperature. Ten healthy subjects (22 ± 3 y, 5 females) underwent 60 min of seated rest in a 32±1 °C or 42±1 °C environment (20% relative humidity). Trials were completed in a counterbalanced order. The motivation to behaviorally thermoregulate was measured using an operant behavior task on a fixed ratio schedule, in which subjects received thermal reinforcement after clicking a button 100 times. The reinforcer was 30 s of cooling on the dorsal aspect of the neck. The motivation to behave was defined as the cumulative number of button clicks over time and behavioral thermoregulation was defined as the change in neck skin temperature. Mean skin temperature was higher throughout the 42 °C versus the 32 °C trial (at 60 min: 36.3±0.5 °C vs. 34.5±0.5 °C, P < .01) and core temperature became higher in this trial 40 min into heat exposure (at 60 min: 37.2±0.2 °C vs. 37.1±0.1 °C, P ≤ .04), but did not differ from pre- heat exposure (P = .81). Neck skin temperature was lower in the 42 °C compared to the 32 °C trial starting at 30 min (33.7±0.8 °C vs. 35.3±0.5°C, P < .01), which was maintained thereafter (P ≤ .04). Cumulative responding for thermal reinforcement was greater in the 42 °C trial compared to the 32 °C trial at 20 min (180±155 clicks vs. 0±0 clicks, P < .01), which persisted thereafter (P < .01). These data indicate that the motivation to behaviorally thermoregulate during passive heat exposure in humans is dependent on the magnitude of increases in skin temperature.
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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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Roussey G, Géhin C, Massot B, Ait Ali I, Bernard T. A Comparative Study of Two Ambulatory Core Temperature Assessment Methods. Ing Rech Biomed 2018. [DOI: 10.1016/j.irbm.2018.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Amiri M, Naim HY. Characterization of Mucosal Disaccharidases from Human Intestine. Nutrients 2017; 9:nu9101106. [PMID: 28994704 PMCID: PMC5691722 DOI: 10.3390/nu9101106] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 09/30/2017] [Accepted: 10/07/2017] [Indexed: 11/16/2022] Open
Abstract
In this study, we used a brush border membrane (BBM) preparation from human small intestine to analyze the proportion and the activity of major intestinal disaccharidases, including sucrase-isomaltase (SI), maltase-glucoamylase (MGAM) and lactase-phlorizin hydrolase (LPH). SI, MGAM and LPH respectively constituted 8.2%, 2.7% and 1.4% of total BBM protein. The activity of SI and LPH decreased threefold after purification from the brush border membrane, which highlights the effect of membrane microdomains on the functional capacity of these enzymes. All of the disaccharidases showed optimal activity at pH 6, over 50% residual activity between pH 5 to pH 7, and increasing activity with rising temperatures up to 45 °C, along with a stable functional structure. Therefore the enzymes can withstand mild intraluminal pH alterations with adequate function, and are able to increase their activity with elevated core body temperature. Our data provide a functional measure for characterization of intestinal disaccharidases under different physiological and pathological conditions.
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Affiliation(s)
- Mahdi Amiri
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover D-30559, Germany.
| | - Hassan Y Naim
- Department of Physiological Chemistry, University of Veterinary Medicine Hannover, Hannover D-30559, Germany.
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Verdegaal ELJMM, Delesalle C, Caraguel CGB, Folwell LE, McWhorter TJ, Howarth GS, Franklin SH. Evaluation of a telemetric gastrointestinal pill for continuous monitoring of gastrointestinal temperature in horses at rest and during exercise. Am J Vet Res 2017. [DOI: 10.2460/ajvr.78.7.778] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Miller KC, Hughes LE, Long BC, Adams WM, Casa DJ. Validity of Core Temperature Measurements at 3 Rectal Depths During Rest, Exercise, Cold-Water Immersion, and Recovery. J Athl Train 2017; 52:332-338. [PMID: 28207294 PMCID: PMC5402531 DOI: 10.4085/1062-6050-52.2.10] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CONTEXT No evidence-based recommendation exists regarding how far clinicians should insert a rectal thermistor to obtain the most valid estimate of core temperature. Knowing the validity of temperatures at different rectal depths has implications for exertional heat-stroke (EHS) management. OBJECTIVE To determine whether rectal temperature (Trec) taken at 4 cm, 10 cm, or 15 cm from the anal sphincter provides the most valid estimate of core temperature (as determined by esophageal temperature [Teso]) during similar stressors an athlete with EHS may experience. DESIGN Cross-sectional study. SETTING Laboratory. PATIENTS OR OTHER PARTICIPANTS Seventeen individuals (14 men, 3 women: age = 23 ± 2 years, mass = 79.7 ± 12.4 kg, height = 177.8 ± 9.8 cm, body fat = 9.4% ± 4.1%, body surface area = 1.97 ± 0.19 m2). INTERVENTION(S) Rectal temperatures taken at 4 cm, 10 cm, and 15 cm from the anal sphincter were compared with Teso during a 10-minute rest period; exercise until the participant's Teso reached 39.5°C; cold-water immersion (∼10°C) until all temperatures were ≤38°C; and a 30-minute postimmersion recovery period. The Teso and Trec were compared every minute during rest and recovery. Because exercise and cooling times varied, we compared temperatures at 10% intervals of total exercise and cooling durations for these periods. MAIN OUTCOME MEASURE(S) The Teso and Trec were used to calculate bias (ie, the difference in temperatures between sites). RESULTS Rectal depth affected bias (F2,24 = 6.8, P = .008). Bias at 4 cm (0.85°C ± 0.78°C) was higher than at 15 cm (0.65°C ± 0.68°C, P < .05) but not higher than at 10 cm (0.75°C ± 0.76°C, P > .05). Bias varied over time (F2,34 = 79.5, P < .001). Bias during rest (0.42°C ± 0.27°C), exercise (0.23°C ± 0.53°C), and recovery (0.65°C ± 0.35°C) was less than during cooling (1.72°C ± 0.65°C, P < .05). Bias during exercise was less than during postimmersion recovery (0.65°C ± 0.35°C, P < .05). CONCLUSIONS When EHS is suspected, clinicians should insert the flexible rectal thermistor to 15 cm (6 in) because it is the most valid depth. The low level of bias during exercise suggests Trec is valid for diagnosing hyperthermia. Rectal temperature is a better indicator of pelvic organ temperature during cold-water immersion than is Teso.
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Poh PYS, Adams AN, Huang M, Allen DR, Davis SL, Tseng AS, Crandall CG. Increased postural sway in persons with multiple sclerosis during short-term exposure to warm ambient temperatures. Gait Posture 2017; 53:230-235. [PMID: 28222370 DOI: 10.1016/j.gaitpost.2017.01.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 01/12/2017] [Accepted: 01/31/2017] [Indexed: 02/02/2023]
Abstract
BACKGROUND Multiple sclerosis (MS) is a neurological disease marked by demyelination and axonal loss. Individuals with MS experience increases in clinical signs and symptoms during heat exposure. OBJECTIVE To test the hypothesis that moderate heat exposure adversely affects postural sway in individuals with MS. METHODS Ten individuals with relapsing-remitting MS (50±8y) and nine controls (47±10y) were examined under a Thermal and a Time Control trial. Following a 30min thermoneutral baseline (25°C, 30% relative humidity (RH)), stand tests randomized with eyes open and closed, were performed. For Thermal, subjects were first exposed to 60min of heating (40°C, 30%RH) followed by 60min of cooling (20°C, 30%RH). For Time Control, subjects remained in a thermoneutral environment throughout. Stand tests were repeated at consistent times in both trials. RESULTS No difference in skin and core temperatures between groups were observed for any trial (P>0.05). During heating, postural sway was higher in MS relative to control subjects (eyes open, P=0.03; eyes closed, P=0.011). No differences in postural sway, regardless of eye status, were observed during the Time Control trial for either group (P>0.05). CONCLUSION These data demonstrate that exposure to a moderate heating environment increases postural sway in patients with MS.
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Affiliation(s)
- Paula Y S Poh
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and UT Southwestern Medical Center, Dallas, TX, USA
| | - Amy N Adams
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and UT Southwestern Medical Center, Dallas, TX, USA
| | - Mu Huang
- Department of Applied Physiology and Wellness, Southern Methodist University, Dallas, TX, USA
| | - Dustin R Allen
- Department of Applied Physiology and Wellness, Southern Methodist University, Dallas, TX, USA
| | - Scott L Davis
- Department of Applied Physiology and Wellness, Southern Methodist University, Dallas, TX, USA
| | - Anna S Tseng
- Neurology Consultants of Dallas, Texas Health Presbyterian Hospital, Dallas, TX, USA
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital and UT Southwestern Medical Center, Dallas, TX, USA.
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Travers GJS, Nichols DS, Farooq A, Racinais S, Périard JD. Validation of an ingestible temperature data logging and telemetry system during exercise in the heat. Temperature (Austin) 2016; 3:208-219. [PMID: 27857951 PMCID: PMC4965001 DOI: 10.1080/23328940.2016.1171281] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 12/12/2022] Open
Abstract
Aim: Intestinal temperature telemetry systems are promising monitoring and research tools in athletes. However, the additional equipment that must be carried to continuously record temperature data limits their use to training. The purpose of this study was to assess the validity and reliability of a new gastrointestinal temperature data logging and telemetry system (e-Celsius™) during water bath experimentation and exercise trials. Materials and Methods: Temperature readings of 23 pairs of e-Celsius (TeC) and VitalSense (TVS) ingestible capsules were compared to rectal thermistor responses (Trec) at 35, 38.5 and 42°C in a water bath. Devices were also assessed in vivo during steady-state cycling (n = 11) and intermittent running (n = 11) in hot conditions. Results: The water bath experiment showed TVS and TeC under-reported Trec (P<0.001). This underestimation of Trec also occurred during both cycling (mean bias vs TVS: 0.21°C, ICC: 0.84, 95% CI: 0.66–0.91; mean bias vs. TeC: 0.44°C, ICC: 0.68, 95% CI: 0.07–0.86, P<0.05) and running trials (mean bias vs. TVS: 0.15°C, ICC: 0.92, 95% CI: 0.83–0.96; mean bias vs. TeC: 0.25, ICC: 0.86, 95% CI: 0.61–0.94, P<0.05). However, calibrating the devices attenuated this difference during cycling and eliminated it during running. During recovery following cycling exercise, TeC and TVS were significantly lower than Trec despite calibration (P<0.01). Conclusion: These results indicate that both TeC and TVS under-report Trec during steady-state and intermittent exercise in the heat, with TeC predicting Trec with the least accuracy of the telemetry devices. It is therefore recommended to calibrate these devices at multiple temperatures prior to use.
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Affiliation(s)
- Gavin J S Travers
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Department of Life Sciences, The Centre for Human Performance, Exercise and Rehabilitation, Division of Sport, Health and Exercise Sciences, Brunel University London, Uxbridge, UK
| | - David S Nichols
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar; Research Institute for Sport and Exercise Science, Liverpool John Moore's University, UK
| | - Abdulaziz Farooq
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital , Doha, Qatar
| | - Sébastien Racinais
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital , Doha, Qatar
| | - Julien D Périard
- Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital , Doha, Qatar
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Cheshire WP. Thermoregulatory disorders and illness related to heat and cold stress. Auton Neurosci 2016; 196:91-104. [DOI: 10.1016/j.autneu.2016.01.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 12/17/2015] [Accepted: 01/05/2016] [Indexed: 01/22/2023]
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Taylor NA, Burdon CA, van den Heuvel AM, Fogarty AL, Notley SR, Hunt AP, Billing DC, Drain JR, Silk AJ, Patterson MJ, Peoples GE. Balancing ballistic protection against physiological strain: evidence from laboratory and field trials. Appl Physiol Nutr Metab 2016; 41:117-24. [DOI: 10.1139/apnm-2015-0386] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This project was based on the premise that decisions concerning the ballistic protection provided to defence personnel should derive from an evaluation of the balance between protection level and its impact on physiological function, mobility, and operational capability. Civilians and soldiers participated in laboratory- and field-based studies in which ensembles providing five levels of ballistic protection were evaluated, each with progressive increases in protection, mass (3.4–11.0 kg), and surface-area coverage (0.25–0.52 m2). Physiological trials were conducted on volunteers (N = 8) in a laboratory, under hot-dry conditions simulating an urban patrol: walking at 4 km·h−1 (90 min) and 6 km·h−1 (30 min or to fatigue). Field-based trials were used to evaluate tactical battlefield movements (mobility) of soldiers (N = 31) under tropical conditions, and across functional tests of power, speed, agility, endurance, and balance. Finally, trials were conducted at a jungle training centre, with soldiers (N = 32) patrolling under tropical conditions (averaging 5 h). In the laboratory, work tolerance was reduced as protection increased, with deep-body temperature climbing relentlessly. However, the protective ensembles could be grouped into two equally stressful categories, each providing a different level of ballistic protection. This outcome was supported during the mobility trials, with the greatest performance decrement evident during fire and movement simulations, as the ensemble mass was increased (–2.12%·kg−1). The jungle patrol trials similarly supported this outcome. Therefore, although ballistic protection does increase physiological strain, this research has provided a basis on which to determine how that strain can be balanced against the mission-specific level of required personal protection.
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Affiliation(s)
- Nigel A.S. Taylor
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Catriona A. Burdon
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Anne M.J. van den Heuvel
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Alison L. Fogarty
- Land Division, Defence Science and Technology, Melbourne VIC 3207, Australia
| | - Sean R. Notley
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Andrew P. Hunt
- Land Division, Defence Science and Technology, Melbourne VIC 3207, Australia
| | - Daniel C. Billing
- Land Division, Defence Science and Technology, Melbourne VIC 3207, Australia
| | - Jace R. Drain
- Land Division, Defence Science and Technology, Melbourne VIC 3207, Australia
| | - Aaron J. Silk
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Mark J. Patterson
- Land Division, Defence Science and Technology, Melbourne VIC 3207, Australia
| | - Gregory E. Peoples
- Centre for Human and Applied Physiology, School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
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Schlader ZJ, Gagnon D, Adams A, Rivas E, Cullum CM, Crandall CG. Cognitive and perceptual responses during passive heat stress in younger and older adults. Am J Physiol Regul Integr Comp Physiol 2015; 308:R847-54. [PMID: 25786484 PMCID: PMC4436980 DOI: 10.1152/ajpregu.00010.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/15/2015] [Indexed: 12/22/2022]
Abstract
We tested the hypothesis that attention, memory, and executive function are impaired to a greater extent in passively heat-stressed older adults than in passively heat-stressed younger adults. In a randomized, crossover design, 15 older (age: 69 ± 5 yr) and 14 younger (age: 30 ± 4 yr) healthy subjects underwent passive heat stress and time control trials. Cognitive tests (outcomes: accuracy and reaction time) from the CANTAB battery evaluated attention [rapid visual processing (RVP), choice reaction time (CRT)], memory [spatial span (SSP), pattern recognition memory (PRM)], and executive function [one touch stockings of Cambridge (OTS)]. Testing was undertaken on two occasions during each trial, at baseline and after internal temperature had increased by 1.0 ± 0.2°C or after a time control period. For tests that measured attention, reaction time during RVP and CRT was slower (P ≤ 0.01) in the older group. During heat stress, RVP reaction time improved (P < 0.01) in both groups. Heat stress had no effect (P ≥ 0.09) on RVP or CRT accuracy in either group. For tests that measured memory, accuracy on SSP and PRM was lower (P < 0.01) in the older group, but there was no effect of heat stress (P ≥ 0.14). For tests that measured executive function, overall, accuracy on OTS was lower, and reaction time was slower in the older group (P ≤ 0.05). Reaction time generally improved during heat stress, but there was no effect of heat stress on accuracy in either group. These data indicate that moderate increases in body temperature during passive heat stress do not differentially compromise cognitive function in younger and older adults.
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Affiliation(s)
- Zachary J Schlader
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York
| | - Daniel Gagnon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Amy Adams
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Eric Rivas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Kinesiology, Texas Woman's University, Denton, Texas; and
| | - C Munro Cullum
- Departments of Psychiatry and Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas;
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Savoie FA, Dion T, Asselin A, Gariepy C, Boucher PM, Berrigan F, Goulet EDB. Intestinal temperature does not reflect rectal temperature during prolonged, intense running with cold fluid ingestion. Physiol Meas 2015; 36:259-72. [DOI: 10.1088/0967-3334/36/2/259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Considerations for the measurement of core, skin and mean body temperatures. J Therm Biol 2014; 46:72-101. [DOI: 10.1016/j.jtherbio.2014.10.006] [Citation(s) in RCA: 228] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/24/2014] [Accepted: 10/27/2014] [Indexed: 11/23/2022]
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Local Insufflation of Warm Humidified CO2 Increases Open Wound and Core Temperature During Open Colon Surgery. Anesth Analg 2012; 115:1204-11. [DOI: 10.1213/ane.0b013e31826ac49f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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