Дисертації з теми "Body core temperature"
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1
Fletcher, Adam C. L. "Increasing core body temperature disrupts sleep /." Title page and summary only, 1995. http://web4.library.adelaide.edu.au/theses/09SB/09sbf612.pdf.
Повний текст джерела
2
SHAHROOZ, MINA. "Re-inventing Core Body Temperature Measurement." Thesis, KTH, Energiteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209832.
Повний текст джерелаАнотація:
Humans are considered an integral part of future energy systems. In this context, constant awareness of human body status is critical for building responsive and intelligent environment that take energy efficiency and human comfort to the highest limits. Core body temperature is one of human body vital signs for body’s proper functioning and comfortability. Continuous non-invasive Core Body Temperature (CBT) measurements is important for patient monitoring and health status tracking in sports, sleep studying and other clinical and care procedures. Currently, there is a lack of precise and versatile methods to capture core body temperature under varying ambient conditions and through practical wearable solutions. Meanwhile, greenTEG AG, Zurich Switzerland, has developed a batch production method enabling the production of small, sensitive and very robust heat flux sensors. The main aim of this project was to develop a commercial product which for the first time measured core body temperature by placement inside a light, affordable wearable hold. This report presents a comprehensive review on heat transfer in human body and thermoregulation concepts in the first chapter followed by the state of the art methods. Then in chapter 2, according to the project design, full description and result discussions of the numerical model of human body developed by the author, was used as a prelude to the experimental tests. The model developed for this study was a Finite Difference model of different tissue layers combined with appropriate convection and radiation heat loss formulations. Tests were conducted through rigorous considerations of real body conditions including variable core body temperature and changing environmental conditions. Numerical tests were also validated by comparing with experimental results. Numerical results provided a precise preview of experimental models’ measurements and were used in the development of experimental setups. One of unique aspects of this study was the fact that the numerical model was used along with the sensor output to capture CBT and was considered a part of final product. In chapter 3, experimental tests on both skin phantom and human trials are discussed together with the sensor design and configuration. Results show that our CBT monitoring system is capable of measuring stable core body temperature under changing environmental conditions. It could also track circadian rhythm of core temperature during sleep, which for the first time, makes it possible for non-invasive miniaturized CBT tracking systems to measure accurate core temperature. These calculations are based on novel algorithms by greenTEG that could compensate for varying environmental conditions.Människan betraktas som en integrerad del av framtidens energisystem. I detta sammanhang är ständig medvetenhet om människokroppen status avgörande för att bygga lyhörd och intelligent miljö som tar energieffektivitet och mänsklig komfort till de högsta gränser. Kroppstemperaturen är en av människokroppen vitala för kroppens funktion och comfort. Kontinuerliga icke-invasiv kroppstemperaturen (CBT) mätningar är viktigt för patientövervakning och spårning hälsotillstånd i idrott, sömn studera och andra kliniska och vårdförfaranden. För närvarande finns det en brist på exakta och mångsidiga metoder för att fånga kroppstemperaturen under varierande omgivningsförhållanden och genom praktiska bärbara lösningar. Samtidigt greenTEG AG, Zurich Schweiz, har utvecklat ett parti produktionsmetod möjliggör produktion av små, känsliga och mycket robusta värmeflödessensorer. Huvudsyftet med projektet var att utveckla en kommersiell produkt som för första gången mätt kroppstemperaturen genom placering i en ljus, prisvärd bärbar håll. Denna rapport presenterar en omfattande översyn på värmeöverföring i människokroppen och termoregulering begrepp i det första kapitlet, följt av toppmoderna metoder. Sedan i kapitel 2, i enlighet med projektets utformning, fullständig beskrivning och resultat diskussioner om den numeriska modellen av människokroppen som utvecklats av författaren, användes som ett förspel till de experimentella testerna. Modellen utvecklades för denna studie var en ändlig skillnad modell av olika vävnadsskikt i kombination med lämpliga konvektion och strålningsvärme förlust formuleringar. Tester genomfördes genom rigorösa överväganden verkliga förhållanden kroppen, inklusive rörliga kroppstemperaturen och växlande miljöförhållanden. Numeriska tester också valideras genom att jämföra med experimentella resultat. Numeriska resultat gav en exakt förhandsvisning av experimentella modeller "mätningar och användes i utvecklingen av experimentella uppställningar. En av unika aspekterna av denna studie var det faktum att den numeriska modellen användes tillsammans med sensorns utsignal för att fånga KBT och ansågs vara en del av slutprodukten. I kapitel 3, är experimentella tester på både hud fantom och mänskliga försök diskuteras tillsammans med sensordesign och konfiguration. Resultaten visar att vårt KBT övervakningssystem är i stånd att mäta en stabil kroppstemperaturen under föränderliga miljöförhållanden. Det kan också spåra dygnsrytm av kärntemperatur under sömnen, som för första gången gör det möjligt för icke-invasiva miniatyriserade KBT tracking system för att mäta exakt kärntemperatur. Dessa beräkningar är baserade på nya algoritmer från greenTEG som kan kompensera för varierande miljöförhållanden.
3
Hegen, Peter. "Continuous Measurements of Core Body Temperature using Body Sensor Networks." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-85465.
Повний текст джерелаАнотація:
Long-term body temperature measurements for research and diagnosis are currently done in hospitals or specialized research labs. This method has several drawbacks: the use of wired ob- trusive sensors (e.g., rectal probes to measure the core body temperature) may be uncomfortable for patients. Furthermore, situations recorded in laboratory settings do not reflect reality as patients are not subject to their normal living environment. Furthermore, it is labor-intensive to regularly check upon patients and care for their well-being. Using small wireless sensor nodes in a body sensor network to measure body functions, one can mostly offset the limitations listed above. For this work, we have developed a wireless sensor node that uses an infrared thermopile as a sensor to unobtrusively measure the core temperature at the tympanic membrane. Due to their construction, these sensors are heavily dependent on the ambient temperature in the surroundings of the sensor packaging. While this does not affect their use in single-shot measurements (e.g., using an ear thermometer), it poses a challenge for continuous measurements, as common living environments do not have constant ambient air temperatures and people frequently commute between different places. These conditions may offset measurements significantly, an important problem for medical applications that require high accuracy. In this work, we employ infrared thermopiles in a body sensor network and characterize their behaviour in various situations, especially in the presence of varying environmental conditions. Based on our observations, we describe methods for post-processing measurements in order to compensate environmental changes and hence get results reflecting reality more closely. Our evaluation shows that these methods can offset the infrared thermopile’s weakness but need further work to achieve the degree of accuracy that is needed for medical applications.
4
Walker, Susan Michelle. "Lowering core body temperature and perceived exertion by three cooling methods." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000881.
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5
Holmes, Alexandra L. "Melatonin and zopiclone reduce sleep onset latency and core body temperature /." Title page and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09SB/09sbh749.pdf.
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6
Guaraldi, Pietro <1979>. "Spinal cord injury: assessment of autonomic state-dependent control of cardiovascular system and body core temperature." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4795/1/2012_Guaraldi_Tesi_PhD.pdf.
Повний текст джерелаАнотація:
Spinal cord injury (SCI) results not only in paralysis; but it is also associated with a range of autonomic dysregulation that can interfere with cardiovascular, bladder, bowel, temperature, and sexual function. The entity of the autonomic dysfunction is related to the level and severity of injury to descending autonomic (sympathetic) pathways.
For many years there was limited awareness of these issues and the attention given to them by the scientific and medical community was scarce. Yet, even if a new system to document the impact of SCI on autonomic function has recently been proposed, the current standard of assessment of SCI (American Spinal Injury Association (ASIA) examination) evaluates motor and sensory pathways, but not severity of injury to autonomic pathways.
Beside the severe impact on quality of life, autonomic dysfunction in persons with SCI is associated with increased risk of cardiovascular disease and mortality. Therefore, obtaining information regarding autonomic function in persons with SCI is pivotal and clinical examinations and laboratory evaluations to detect the presence of autonomic dysfunction and quantitate its severity are mandatory.
Furthermore, previous studies demonstrated that there is an intimate relationship between the autonomic nervous system and sleep from anatomical, physiological, and neurochemical points of view. Although, even if previous epidemiological studies demonstrated that sleep problems are common in spinal cord injury (SCI), so far only limited polysomnographic (PSG) data are available. Finally, until now, circadian and state dependent autonomic regulation of blood pressure (BP), heart rate (HR) and body core temperature (BcT) were never assessed in SCI patients.
Aim of the current study was to establish the association between the autonomic control of the cardiovascular function and thermoregulation, sleep parameters and increased cardiovascular risk in SCI patients.
7
Guaraldi, Pietro <1979>. "Spinal cord injury: assessment of autonomic state-dependent control of cardiovascular system and body core temperature." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4795/.
Повний текст джерелаАнотація:
Spinal cord injury (SCI) results not only in paralysis; but it is also associated with a range of autonomic dysregulation that can interfere with cardiovascular, bladder, bowel, temperature, and sexual function. The entity of the autonomic dysfunction is related to the level and severity of injury to descending autonomic (sympathetic) pathways.
For many years there was limited awareness of these issues and the attention given to them by the scientific and medical community was scarce. Yet, even if a new system to document the impact of SCI on autonomic function has recently been proposed, the current standard of assessment of SCI (American Spinal Injury Association (ASIA) examination) evaluates motor and sensory pathways, but not severity of injury to autonomic pathways.
Beside the severe impact on quality of life, autonomic dysfunction in persons with SCI is associated with increased risk of cardiovascular disease and mortality. Therefore, obtaining information regarding autonomic function in persons with SCI is pivotal and clinical examinations and laboratory evaluations to detect the presence of autonomic dysfunction and quantitate its severity are mandatory.
Furthermore, previous studies demonstrated that there is an intimate relationship between the autonomic nervous system and sleep from anatomical, physiological, and neurochemical points of view. Although, even if previous epidemiological studies demonstrated that sleep problems are common in spinal cord injury (SCI), so far only limited polysomnographic (PSG) data are available. Finally, until now, circadian and state dependent autonomic regulation of blood pressure (BP), heart rate (HR) and body core temperature (BcT) were never assessed in SCI patients.
Aim of the current study was to establish the association between the autonomic control of the cardiovascular function and thermoregulation, sleep parameters and increased cardiovascular risk in SCI patients.
8
Gibson, Robert H. "The effect of elevated core temperature upon excess post exercise oxygen consumption." Virtual Press, 1995. http://liblink.bsu.edu/uhtbin/catkey/941356.
Повний текст джерелаАнотація:
A great deal of research has been done to assess the effects of exercise intensity and duration on excess post-exercise oxygen consumption (EPOC). But the effects of an elevated core temperature (Tc) post-exercise have not been directly examined. To assess the effects of an elevated Tc on EPOC, eight healthy, active male subjects (27.5 ± 6.1 years) underwent two 45 minute exercise trials at =70% VO2max in an environmental chamber (36 °C / 10% RH) followed by a 45 minute recovery in either the environmental chamber (42 °C / 10% RH) wearing insulating clothing (HC), or in the ambient conditions of the testing lab (22 °C / 42% RH) without any additional clothing (AM). Oxygen consumption (V02), minute ventilation (VE), heart rate (HR), and rectal temperature (Tc) were recorded pre-, exercise, and post- during both trials. Subjects were monitored postexercise for 45 minutes. EPOC was determined by subtracting pre-trial V02 from the recovery V02 until the difference between the values equaled zero or until 45 minutes had elapsed. Within 25 minutes post-exercise, V02 during the AM recovery had returned to near resting levels (p = 0.146), while V02 during the HC recovery remained significantly elevated for at least 45 minutes (p = 0.027). Given that V02 remained significantly elevated through 45 minutes of recovery, and that all other measured variables (HR, VE, and respiratory exchange ratio) were significantly affected during the HC recovery, it is clear that an elevated Tc has an effect on EPOC.School of Physical Education
9
Kalathil, Robins T. "Assessment of Uncertainty in Core Body Temperature due to Variability in Tissue Parameters." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479819529740889.
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10
Grewar, John Duncan. "Use of temperature sensitive microchip transponders to monitor body temperature and pyrexia in Thoroughbred foals." Diss., University of Pretoria, 2009. http://hdl.handle.net/2263/22799.
Повний текст джерелаАнотація:
The aim of this study was to evaluate temperature data collected from Thoroughbred foals between birth and shortly after weaning. It provides a valuable survey with epidemiological conclusions providing insight into the temperature trends and pyretic occurrences of Thoroughbred foals during this age period. Temperature data were collected using telemetry from temperature sensitive microchips implanted into newborn foals. The system of inputting and storing temperature data was completely electronic and this study evaluated this system. It was found that this system was stable and allowed the evaluation of large amounts of frequently acquired data with little human intervention. The data obtained resulted in the valuable evaluation of age associated body temperature trends within the foals as well as providing an indication of the extent and epidemiology of pyrexia within the study cohort. The system of evaluating temperatures based both on the individual day value as well as on each individual foals prior series of temperatures shows that the use of these two criteria can be utilised simultaneously. The study provides basic information which future researchers using similar systems can use to objectively set criteria for pyrexia. An outbreak of equine encephalosis also occurred during the study period and this provided much needed prospective epidemiological information for such an outbreak, something which has not previously been documented. CopyrightDissertation (MSc (Veterinary Science))--University of Pretoria, 2009.
Production Animal Studies
unrestricted
11
Friesen, Brian J. "Whole-Body Cooling Following Exercise-Induced Hyperthermia: Biophysical Considerations." Thèse, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/30510.
Повний текст джерелаАнотація:
This thesis 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 (2°C, CWI) and temperate water immersion (26°C, TWI) following exercise-induced hyperthermia (end-exercise rectal temperature of 40°C). Individuals with a High AD/LBM (315 cm2/kg) had a ~1.7-fold greater overall rectal cooling rate relative to those with Low AD/LBM (275 cm2/kg) during both CWI and TWI. Further, overall rectal cooling rates during CWI were ~2.7-fold greater than during TWI for both the High and Low AD/LBM groups. Study findings show that AD/LBM must be considered when determining the duration of the immersion period. However, CWI provides the most effective cooling treatment for EHS patients irrespective of physical differences between individuals.
12
Reid, Kathryn J. "Day-time administration of melatonin : effects on core body temperature, sleep propensity and performance /." Title page and abstract only, 1993. http://web4.library.adelaide.edu.au/theses/09SB/09sbr356.pdf.
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13
Bonds, Quenton. "A Microwave Radiometer for Close Proximity Core Body Temperature Monitoring: Design, Development, and Experimentation." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3574.
Повний текст джерелаАнотація:
Presented is a radiometric sensor and associated electromagnetic propagation models, developed to facilitate non-invasive core body temperature extraction. The system has been designed as a close-proximity sensor to detect thermal emissions radiated from deep-seated tissue 1 cm – 3 cm inside the human body. The sensor is intended for close proximity health monitoring applications, with potential implications for deployment into the improved astronaut liquid cooling garment (LCG). The sensor is developed for high accuracy and resolution. Therefore, certain design issues that distort the close proximity measurement have been identified and resolved. An integrated cavity-backed slot antenna (CBSA) is designed to account for antenna performance degradation, which occurs in the near field of the human body. A mathematical Non-Contact Model (NCM) is subsequently used to correlate the observed brightness temperature to the subsurface temperature, while accounting for artifacts induced by the sensor’s remote positioning from the specimen. In addition a tissue propagation model (TPM) is derived to model incoherent propagation of thermal emissions through the human body, and accounts for dielectric mismatch and losses throughout the intervening tissue layers. The measurement test bed is comprised of layered phantoms configured to mimic the electromagnetic characteristics of a human stomach volume; hence defines the human core model (HCM). A drop in core body temperature is simulated via the HCM, as the sensor monitors the brightness temperature at an offset distance of approximately 7 mm. The data is processes through the NCM and TPM; yielding percent error values < 3%. This study demonstrates that radiometric sensors are indeed capable of subsurface tissue monitoring from the near field of the body. However, the following components are vital to achieving an accurate measurement, and are addressed in this work: 1) the antenna must be designed for optimum functionality in close proximity to biological media; 2) a multilayer phantom model is needed to accurately emulate the point of clinical diagnosis across the tissue depth; 3) certain parameters of the non-contact measurement must be known to a high degree of accuracy; and 4) a tissue propagation model is necessary to account for electromagnetic propagation effects through the stratified tissue.
14
Zachariah, Swarup Alex. "Methodology to predict core body temperature, cardiac output, and stroke volume for firefighters using a 3D whole body model." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439310929.
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15
Rabby, Quyymun Shorno. "A Preliminary Study of Whole Body Hyperthermia Interventions: Correlation Between Core Body Temperature and Depression in Major Depressive Disorder Patients." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/321920.
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16
Fallis, Wendy M. "Core and bladder temperature gradient in critically ill adults : urine flow rate as a factor /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/7315.
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17
Grimaldi, Daniela <1974>. "Narcolepsy: state-dependent autonomic regulation and circadian control of blood pressure, heart rate, body core temperature." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1706/1/grimaldi_daniela_tesi.pdf.
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18
Grimaldi, Daniela <1974>. "Narcolepsy: state-dependent autonomic regulation and circadian control of blood pressure, heart rate, body core temperature." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1706/.
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19
Moreno, Maria. "The role of ionotropic glutamate receptors in the dorsomedial hypothalamus in the increase in core body temperature evoked by interoceptive and exteroceptive stresses in rats." Thesis, Connect to resource online, 2010. http://hdl.handle.net/1805/2107.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--Indiana University, 2010.Title from screen (viewed on March 3, 2010). Department of Pharmacology and Toxicology, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Joseph A. DiMicco, Sherry F. Queener, Daniel E. Rusyniak, Michael R. Vasko. Includes vitae. Includes bibliographical references (leaves 126-147).
20
Johnson, Jared. "Use of evaporative cooling systems and their effects on core body temperature and lying times in dairy cattle." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20521.
Повний текст джерелаАнотація:
Master of ScienceAnimal Sciences and Industry
Micheal J. Brouk
Study 1 was performed to assess the effect of an evaporative cooling system (ECS) on core body temperature (CBT) and lying times in lactating dairy cows. Respiration rates and rear udder temperatures (T[subscript u]) were also measured. Trial 1 contained 3 environmental treatments while trial 2 contained 2 environmental treatments. Treatments were: OFF (Cyclone fans and fog shut off), FAN (Cyclone fans only, no fog), and FANFOG (Cyclone fans and fog on) and cows exposed to these 3 environments were housed in a bedded pack barn (PACK) equipped with an ECS or a tie-stall barn (TIE). TIE and PACK cows moved between barns every 8 h for milking and both groups moved opposite of each other. Ambient, barn temperature and relative humidity (RH) measurements in addition to vaginal temperatures and lying times were recorded by sensors which took measurements at 1 min intervals. Respiration rates (BPM), for PACK cows during FANFOG were reduced (P < 0.05) when compared to TIE (53 ± 2.0 vs 64 ± 2.0, respectively) in trial 1. Similar results were found in trial 2. Rear udder temperature was measured and found to be decreased (P < 0.05) in PACK cows while housed under FANFOG vs TIE in trial 1. These results could not be repeated in trial 2 because of greater ambient temperatures. Core body temperature (CBT) was reduced during each trial as shown by less time spent above 39.0°C during FANFOG. During trial 2, PACK spent 5.7 and 8.5 h/d less over a CBT of 39.0°C compared to TIE cows. Total daily lying time was tracked and found to increase for cows exposed to the ECS during PACK but no difference between PACK and TIE. In study 2, the same ECS was used but its effects on nonlactating dairy cows were studied. There was a treatment by h interaction for vaginal temperature showing the greatest effects during the afternoon h where FANFOG had numerically decreased CBT vs FAN. FANFOG cows spent reduced time over a CBT of 39.0°C and greater time < 38.0°C. FANFOG cows also had increased lying times of 1.7 h/d compared to FAN.
21
Pyke, Andrew J. "Heat strain evaluation of overt and covert body armour." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/62933/1/Andrew_Pyke_Thesis.pdf.
Повний текст джерелаАнотація:
Body armour is designed to protect the wearer from knife and bullet assault but may have an unintended consequence of increasing the risk of the wearer to developing heat strain. A controlled, laboratory based evaluation was undertaken of two non-military lightweight body armour garments. The study found that the heat strain observed while wearing covert and overt body armour, in a hot and humid environment, was negligible compared to not wearing any body armour.
22
Winke, Molly Rebecca. "PRECOOLING AND RUNNING ECONOMY." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/563.
Повний текст джерелаАнотація:
Precooling, or a reduction in core temperature (Tc) has been demonstrated to be a potent enhancer of endurance running performance, however there is no known mechanism for this improvement. By holding the exercise workload constant, changes in variables such as running economy (RE), heart rate, and ventilation (VE) can be determined as a result of precooling. Improved running economy, or a reduced oxygen cost of a specific workload, is linked to improved exercise performance. Purpose: To determine the changes in flexibility, RE, heart rate, VE, and Tc during running at a constant workload following cool water immersion and to determine any sex-specific responses. Methods: Fourteen well-trained runners (8 males and 6 females) completed four treadmill runs at a sex-specific velocity (8.0 mph for females and 8.6 mph for males). The first two runs served as accommodation trials. The third and fourth runs were preceded by either cool water immersion (24.8oC) for 40 minutes or quiet sitting. Oxygen consumption, heart rate, Tc, VE, and flexibility were measured during both experimental trials. Results: Running economy did not change as a result of the precooling treatment, whereas Tc and heart rate were reduced by 0.4oC and 5 beats per minute, respectively. Minute ventilation was reduced in the female subjects only (1.4 liters/min). Sex differences were apparent in Tc, heart rate, VE, and flexibility response. Conclusion: While the precooling procedure was effective in reducing Tc and heart rate, RE did not change. Thus, improvements in RE cannot explain the dramatic enhancements of endurance running performance that often occur post-cooling. Differences between male and female subjects in response to precooling were identified, most notably in VE.
23
Lackland, William S. "Effects of changes in plasma volume, osmolality and sodium levels on core temperature during prolonged exercise in heat." Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/43886.
Повний текст джерелаАнотація:
Six adult males of similar body composition and aerobic capacity were tested to study the effects of changes in plasma volume (PV), osmolality (OSM) and sodium (Na+) on core temperature (Tc) under three exercise-thermoregulatory stress conditions. The protocol consisted of 120 min of upright stationary cycling at 50% V02max under neutral (24° C, 50% RH) - euhydrated (NE), hot (35°C, 50% RH) - euhydrated (HE), and hot-hypohydrated (HH) environmental conditions. Venous blood samples were obtained at -30 min, 0 min and at 15 min intervals through a 30 min recovery and were analyzed for blood hematocrit and hemoglobin, and for plasma osmolality and sodium. Hematocrit and hemoglobin were used to calculate relative changes in plasma volume. Tc showed qualitatively similar linear increases in the first 45 min of each trial. At 60 min, Tc in the NE trial plateaued at 37.9°C. In the HE trial, Tc continued to show a slight further increase after 45 min while in NE it became significantly (p<0.05) lower at 45 min as compared to HE and HH; at 60 min of exercise, the core temperature of all three trials differed significantly (p<0.05), with HH being the highest (38.3°C). Percent change in plasma volume was not different between trials, but did show the greatest decrease in all trials from O to 15 min of the exercise phase with at least -4.3%. Osmolality was significantly different (p<0.05) between the NE (X = 283.3 m0smol/kg) and the HH (X = 292.5 m0smo1/kg). Plasma sodium was significantly (p<0.05) higher for all intervals of HH (X = 137.9 meq/L) as compared to the NE (X = 135.1 meq/L) and HE (X = 134.8 meq/L). These data suggest that core temperature (Tc) increase in moderate intensity endurance exercise is less related to a decreased circulating plasma volume, but is more strongly associated with rising osmolality, specifically the increase in the Na+ electrolyte, which occur with progressive hypohydration.
Master of Science
24
Schmidt, Mariana [Verfasser]. "Evaluation of core body temperature by two non-invasive methods of infrared thermography for health monitoring in pigs / Mariana Schmidt." Berlin : Freie Universität Berlin, 2015. http://d-nb.info/1066238723/34.
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Kravčenko, Laima. "Miego ir paros ciklo įtaka sveikų žmonių atminčiai." Bachelor's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130910_100643-30951.
Повний текст джерелаАнотація:
Tyrimo objektas: miego ir paros ciklo įtaka atminčiai, sveikiems asmenims. Darbo tikslas: nustatyti kaip miegas ir paros ciklas veikia sveikų žmonių atmintį. Darbo uždaviniai: 1. Išsiaiškinti, kaip vidinės kūno temperatūros pokyčiai veikia nuotaiką ir mieguistumą. 2. Ištirti, kaip paros ciklo metu kinta atminties aktyvumas. 3. Palyginti atminties aktyvumą po išsimiegotos nakties su atminties aktyvumu po bemiegės nakties. Tyrimo hipotezės: vidinės kūno temperatūros svyravimai atspindi atminties aktyvumą. Tyrimo metodai: Mokslinės literatūros analizė. Empirinis tyrimas naudojat kompiuterinę testų programą ANAM4. Statistinė duomenų analizė. Išvados: 1. Vidinė kūno temperatūra veikia, mieguistumą ir nuotaiką. Kai nakties metu vidinė kūno temperatūra krenta, padidėja mieguistumas ir pablogėja nuotaika, o kai dienos metu vidinė kūno temperatūra kyla, mažėja mieguistumas ir pagerėja nuotaika. 2. Vidinės kūno temperatūros svyravimai atspindi darbinės atminties aktyvumo svyravimus, kai reikia atsiminti išmoktus objektus. O atliekant matematinius skaičiavimus ir erdvinio suvokimo užduotis, atmintis aktyvumo svyravimai nesutapo su vidinės kūno temperatūros svyravimais. 3. Atmintis aktyvumas yra geresnis dieną po išsimiegotos nakties, lyginant su diena po bemiegės nakties.The object of research: sleep and circadian rhythm effects on healthy people memory. The aim of research: to find out how sleep and circadian rhythm effects memory in healthy The goals of research: 1. Find out, how core body temperature effects mood and sleepiness. 2. Determine, how memory activity changes in circadian rhythm. 3. Compare memory activity after sleep night with memory activity after sleepless. Hypothesis: core body temperature reflects fluctuations in memory activity. Research methods: Scientific literature analysis. Empiric research using computer cognitive tests program ANAM4. Statistical data analysis. Conclusions: 1. Core body temperature affects sleepiness and mood. When at night time core body temperature decreases, sleepiness increase and mood impairs, and when at day time core body temperature increases, sleepiness decreases and mood improves. 2. Core body temperature fluctuations reflects memory activity, when need to recognize learned objects. In mathematical computation and spatial processing, memory activity does not match with core body temperature fluctuations. 3. Memory activity is higher during day after sleep night, comparing with memory activity after sleepless night.
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Christ, Gregory J. "EEG slow wave sleep and slow wave activity in extended sleep with bright light induced phase shifts of core body temperature." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/6571.
Повний текст джерелаАнотація:
In this study, the time courses of slow wave sleep (SWS) and EEG slow wave activity (SWA) were examined in relation to core body temperature (CBT) during extended sleep periods of 15 hours. This investigation examined the merits of a hypothetical 12-hour rhythm of SWS to: (1) confirm its existence; (2) see if it was reflected by the more objective measure of SWA (power spectral analysis); and (3) determine if there was any relationship between this 12-hour rhythm and the CBT rhythm. In Study 1, 7 subjects (age 18-22 years) slept in the laboratory for 3 consecutive nights (2 of 8 hours, then 1 of 15 hours). Rectal CBT was monitored during sleep periods. The main findings were that SWS and SWA both significantly increase in the final 3-hour block over the center 3-hour block, and that these late increases were not related to waking after sleep onset (WASO) or rapid eye movement (REM) sleep. Five of the 7 subjects showed a return of SWA, which was defined by the maximum 15 minute running average in the last 5 hours exceeding the same measure for the previous 4 hours (about 2 sleep cycles with lower SWA). With CBT phase defined as the delay from sleep onset to CBT minimum, it was found that late SWS (in the last 3 hours), and magnitude of the SWA return had significant positive relationships to CBT phase. In Study 2, 3 subjects (age 19, 21, and 29) were studied for 4 series of 4 consecutive nights, with bedtime at 23:30h on all nights. Two series served as baseline (8HBL, and 6HBL). During one series (ML) CBT rhythm was phase advanced using morning bright light (7000-11000 lux, 6:00h-9:00h), and during another series (EL) CBT was delayed using evening bright light (20:00h-23:00h). Subjects were kept in dim light (250 lux) during these morning and evening periods for the 8HBL and 6HBL. A range of CBT phase to sleep timing combinations resulted, with ML always phase advanced relative to EL. CBT phase plotted against late SWS and SWA measures showed a positive association between CBT phase and timing of SWA return (except in one subject (#3)), and a smaller positive association to SWA in the last 3 hours (except in one subject (#1)). When data from Study 1 and the equivalent 8HBL of Study 2 were combined, SWS and SWA late in the sleep period were not significantly related to WASO or REM, and magnitude of the SWA return was statistically significant. There was also a significant relationship between CBT phase and late SWS, magnitude of SWA return, and timing of the SWA return, but not with SWA in the last 3 hours. The data were consistent with a 12-hour rhythm of SWS and SWA, in which the minor pole does not depend solely on WASO or REM, and is related in timing and magnitude to the CBT rhythm. Magnitude of both poles are likely influenced by prior amounts of waking, but the special conditions of extended sleep illustrate the association of the minor pole to the CBT rhythm.
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DeChant, Mallory. "The Effects of Climate, Psychological, and Physical Stressors on Human Remains Detection Canines." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2276.
Повний текст джерелаАнотація:
Ten canines were utilized in a repeated design to examine the effects of stress associated with work on activity expenditure, core body temperature, and salivary cortisol. However, only eight canines had valid data results due to the ninth canine having a metabolic syndrome that was not diagnosed. The tenth canine was removed from the study prior to initiation of the search scenario due to aggression. The objective was to observe the impact of stressors associated with work on activity expenditure, core body temperature, and salivary cortisol in human remains detection canines. Nine canines were randomly assigned to 1 of 3 simulated search sites which each had two repetitions 1A) RU (rubble area with two concealed partial cadavers); 1B) RU (open crop field with one concealed partial cadaver); 2A) WA (wooded area with two concealed partial cadavers elevated off the ground); 2B) WA (wooded area with two concealed partial cadavers); 3A) MC (mass casualty area with eight exposed full body cadavers); 3B) MC (mass casualty area with five buried full body cadavers). Canines searched for an average of 90 minutes at each site which was then followed by a 10 minute rotation period where canines randomly rotated to one of the other two sites. Upon completion of the third site, canines repeated the first site location. There was a 69 minute rest period between the second and third rotation. Canines were rotated through search sites such that one canine was actively working (AW), the next canine was waiting to work (WW) and was exposed to visual and auditory stimulation in preparation for work and the third canine in the rotation was not working (NW) and crated in the handler’s vehicle with no visual or auditory stimulation associated with work 100 feet from WW area. Total activity expenditure was not influenced by site (P = 0.89) which may indicate detection canines were efficient in expending energy during this study. This correlated with the walk activity expenditure by site as it did not differ based on site (P = 0.16). The canines expended a similar amount of walk energy at each site and this may demonstrate that canines spent more time searching and in scent of the cadaver(s). Conversely, run activity expenditure was influenced by site (P = 0.03), specifically RU site was greater than MC site. When further comparison of the RU repetitions was analyzed, the second repetition was greater than the first in run activity expenditure (P < 0.0001). Canines at the RU site during the second repetition had an easier ability to run compared to the first repetition because of the nature of the site. Total activity expenditure was influenced by rotation (P = 0.04) but was not influenced by rotation within site (P = 0.17). The first rotation was greater than the fourth rotation which may indicate a psychological stressor such as anticipation of the work and possible acclimation of the site. The fourth rotation was at the same location site as the first rotation and canines did not have the novelty of the site as a psychological stressor during the fourth rotation. Canines that did not have exposure to full body cadavers prior to this study did not have greater total activity expenditure (P = 0.46) at the MC site compared to canines that did have exposure to full body cadavers prior to the study. There was an effect of phase on core body temperature (P = 0.0003). However, 95.3% of canines had their core body temperature peaked in the NW phase directly after the AW phase. Which demonstrates that core body temperature continued to increase post exercise. There was also a plateau in the core body temperature for 18 minutes post exercise which could indicate peripheral vasodilation. Attenuation of core body temperature occurred 37 minutes after cessation of the AW phase. There was an effect of site (P < 0.0001), rotation (P < 0.0001), and rotation within site (P < 0.0001) on core body temperature. This may indicate that there was a boundary layer stimulus that acted as a psychological stressor. In addition, the second and third rotation were greater than the first and fourth rotation which is most likely due to the increase in humidity during the second rotation. Core body temperature was impacted by total activity expenditure (P < 0.0001) which is to be expected with increased exercise, core body temperature increases. Salivary cortisol was influenced by site (P = 0.003), specifically the WA site was greater than the MC and the RU site. The WA site may have had a stronger psychological stressor with the tree lines compared to the MC and the RU sites. Rotation within site did impact salivary cortisol (P < 0.0001). However, rotation alone did not influence salivary cortisol (P = 0.42). Core body temperature did not impact salivary cortisol (P = 0.18). Total activity expenditure did not affect salivary cortisol (P = 0.73). Salivary cortisol and age of canine did display a pattern (P = 0.003). Salivary cortisol and exposure to prior full body cadaver did not displayed a pattern (P = 0.78). Based on these results, some physical stressors such as site, rotation, and exercise impacted activity expenditure, core body temperature, and salivary cortisol. This thesis provides limited data dissemination on three physiological parameters that may be impacted on independent variables that are associated with search scenario work. More research is needed to confirm if these specific stressors observed impact activity expenditure, core body temperature, and salivary cortisol in human remains detection canines.
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Cajochen, Christian Lorenz Anton. "Heart rate, submental EMG and core body temperature in relation to EEG slow-wave activity during human sleep : effect of light exposure and sleep deprivation /." [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10384.
Повний текст джерела
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Musolin, Kristin M. "Evaluating the Effects of Heat Stress on the Cardiovascular System and Psychophysical Response of Firefighters." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1305892912.
Повний текст джерела
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Schneider, Randi Lynn. "Persisiting Sensitization of Depressive-Like Behavior and Thermogenic Response During Maternal Separation in Pre- and Post Weaning Guinea Pigs." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1309794651.
Повний текст джерела
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Cramer, Matthew Nathaniel. "The Contribution of Body Morphology to Individual Variability in the Thermoregulatory Responses to Exercise, and the Effect of Altered Skin Blood Flow on Heat Loss Potential." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32901.
Повний текст джерелаАнотація:
Three studies were performed to examine biophysical sources of individual variability in the thermoregulatory responses to exercise, and the influence of skin blood flow on heat loss potential during severe heat stress. Study 1 investigated whether unbiased comparisons of changes in rectal temperature (ΔTre) should be compared at a fixed absolute rate of heat production (Hprod; W) or a fixed Hprod per unit mass (W/kg), and whether local sweat rates (LSR) should be compared at a fixed evaporative requirement for heat balance (Ereq; W) or a fixed Ereq per unit of surface area (W/m2), between independent groups of unequal body mass and body surface area (BSA). Study 2 examined whether individual variation in ΔTre, whole-body sweat loss (WBSL), and steady-state LSR is best explained by biophysical factors related to Hprod, Ereq, and body size, and if factors related to aerobic fitness (VO2max) and body fatness correlate with the residual variance in these responses. Study 3 tested whether alterations in skin blood flow shift the critical vapour pressure (Pcrit) above which core temperature could no longer be regulated in hot/humid conditions, indicating altered heat loss potential from the skin. In study 1, exercise at fixed absolute Hprod and Ereq resulted in greater ΔTre and LSR in smaller individuals (smaller mass and BSA), but exercise at set Hprod in W/kg and Ereq in W/m2 resulted in no differences in ΔTre and LSR, respectively, regardless of body size and %VO2max. In study 2, 50-71% of the individual variation in ΔTre, whole-body sweat loss (WBSL), and steady-state LSR was explained by Hprod (W/kg), absolute Ereq (W) and Ereq (W/m2) respectively, while body fat percentage and %VO2max contributed merely 1-4% to the total variability. In study 3, despite a ~20% lower skin blood flow, Pcrit was unaffected by a large reduction in skin blood flow following iso-smotic dehydration, with no differences in core and skin temperatures and sweating observed. Collectively, these findings suggest that between-group comparisons and modelling of thermoregulatory responses must first consider biophysical factors related to metabolic heat production and body size, rather than factors related to VO2max and body fatness. Furthermore, lower levels of skin blood flow may not impair maximum heat dissipation from the skin to the external environment during severe passive heat stress as previously thought.
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Hunt, Andrew Philip. "Heat strain, hydration status, and symptoms of heat illness in surface mine workers." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/44039/1/Andrew_Hunt_Thesis.pdf.
Повний текст джерелаАнотація:
The aim of the research program was to evaluate the heat strain, hydration status, and heat illness symptoms experienced by surface mine workers. An initial investigation involved 91 surface miners completing a heat stress questionnaire; assessing the work environment, hydration practices, and heat illness symptom experience. The key findings included 1) more than 80 % of workers experienced at least one symptom of heat illness over a 12 month period; and 2) the risk of moderate symptoms of heat illness increased with the severity of dehydration. These findings highlight a health and safety concern for surface miners, as experiencing symptoms of heat illness is an indication that the physiological systems of the body may be struggling to meet the demands of thermoregulation. To illuminate these findings a field investigation to monitor the heat strain and hydration status of surface miners was proposed. Two preliminary studies were conducted to ensure accurate and reliable data collection techniques. Firstly, a study was undertaken to determine a calibration procedure to ensure the accuracy of core body temperature measurement via an ingestible sensor. A water bath was heated to several temperatures between 23 . 51 ¢ªC, allowing for comparison of the temperature recorded by the sensors and a traceable thermometer. A positive systematic bias was observed and indicated a need for calibration. It was concluded that a linear regression should be developed for each sensor prior to ingestion, allowing for a correction to be applied to the raw data. Secondly, hydration status was to be assessed through urine specific gravity measurement. It was foreseeable that practical limitations on mine sites would delay the time between urine collection and analysis. A study was undertaken to assess the reliability of urine analysis over time. Measurement of urine specific gravity was found to be reliable up to 24 hours post urine collection and was suitable to be used in the field study. Twenty-nine surface miners (14 drillers [winter] and 15 blast crew [summer]) were monitored during a normal work shift. Core body temperature was recorded continuously. Average mean core body temperature was 37.5 and 37.4 ¢ªC for blast crew and drillers, with average maximum body temperatures of 38.0 and 37.9 ¢ªC respectively. The highest body temperature recorded was 38.4 ¢ªC. Urine samples were collected at each void for specific gravity measurement. The average mean urine specific gravity was 1.024 and 1.021 for blast crew and drillers respectively. The Heat Illness Symptoms Index was used to evaluate the experience of heat illness symptoms on shift. Over 70 % of drillers and over 80 % of blast crew reported at least one symptom. It was concluded that 1) heat strain remained within the recommended limits for acclimatised workers; and 2) the majority of workers were dehydrated before commencing their shift, and tend to remain dehydrated for the duration. Dehydration was identified as the primary issue for surface miners working in the heat. Therefore continued study focused on investigating a novel approach to monitoring hydration status. The final aim of this research program was to investigate the influence dehydration has on intraocular pressure (IOP); and subsequently, whether IOP could provide a novel indicator of hydration status. Seven males completed 90 minutes of walking in both a cool and hot climate with fluid restriction. Hydration variables and intraocular pressure were measured at baseline and at 30 minute intervals. Participants became dehydrated during the trial in the heat but maintained hydration status in the cool. Intraocular pressure progressively declined in the trial in the heat but remained relatively stable when hydration was maintained. A significant relationship was observed between intraocular pressure and both body mass loss and plasma osmolality. This evidence suggests that intraocular pressure is influenced by changes in hydration status. Further research is required to determine if intraocular pressure could be utilised as an indirect indicator of hydration status.
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Chaimanonart, Nattapon. "Adaptively Radio Frequency Powered Implantable Multi-Channel Bio-Sensing Microsystem for Untethered Laboratory Animal Real-Time Monitoring." Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1247265060.
Повний текст джерелаАнотація:
Thesis (Ph.D.)--Case Western Reserve University, 2009Title from PDF (viewed on 19 August 2009) Department of Electrical Engineering and Computer Science Includes abstract Includes bibliographical references Available online via the OhioLINK ETD Center
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Brake, Derrick John. "The Deep Body Core Temperatures, Physical Fatigue and Fluid Status of Thermally Stressed Workers and the Development of Thermal Work Limit as an Index of Heat Stress." Thesis, Curtin University, 2002. http://hdl.handle.net/20.500.11937/621.
Повний текст джерелаАнотація:
Objectives: To determine the physiological strain on industrial workers under thermal stress on extended shifts. To continuously measure deep body core temperatures, heart rates, fluid intake, changes in hydration state and physical fatigue in order to establish acceptable levels of physiological strain. To develop a rational heat stress index compatible with these limits. To design working-in-heat protocols for a self-paced workforce. Methods: A series of studies was conducted over 77 shifts on a group of approximately 50 male volunteers working in thermally stressful environments. Continuously- recorded deep body core temperatures, heart rates, fluid consumption, urinary specific gravity and physical fatigue were measured and recorded. A new field protocol was developed to assess physical fatigue over the working shift. An original methodology was developed to allow any heat stress index to be assessed on a comparative basis with any other index. A review of the commonly used occupational heat stress indices was conducted. A new rational heat stress index was developed, based on existing biophysical relationships and recommended physiological strain limits of deep body core temperature and sweat rate. New protocols designed for self-paced work incorporating the significant risk factors for heat illness were developed and implemented in a workforce of approximately 2000 workers exposed to heat stress. The previous protocols used a shortened shift as the primary intervention to protect worker health. The subsequent protocols removed the shortened shift and replaced this with a range of other interventions. Deep body core temperature, heart rate, fluid consumption, hydration state and fatigue were measured before and after the changes in protocols.Results: Comparisons of heat stress indices confirmed the wide divergence in guidance provided by many of the commonly-used indices in terms of acceptable working environments. It also highlighted a number of serious shortcomings in the most widely-used indices, especially WBGT and ISO7933. A new, rational heat stress index called Thermal Work Limit (TWL) was developed. This included development of a computer model incorporating key thermal physiological parameters (deep body core temperature, mean skin temperature, sweat rate, skin wettedness). There was no increase in heat stress (as indicated by average workplace environmental conditions), deep body core temperature, mean heart rate, or changes in hydration status after the changes in protocols. Average environmental conditions were severe (WBGT 30.9° C, sd 2.0° C, range 25.7-35.2° C). Environmental conditions in the study were much hotter than those considered acceptable under standards such as the ACGIH. The results showed that miners regularly exceeded those limits allowable under most current indices in terms of maximum deep body core temperature (avg 38.3° C, std dev 0.4° C), maximum temperature rise (1.4° C, 0.4° C) and maximum heat storage (431 kJ, 163 kJ), without reporting any symptoms of heat illness. A significant component of the observed elevated core temperatures was due to the normal circadian rhythm, which was measured at 0.9° C (std dev 0.2° C). Evidence was found that workers "self-pace" when under thermal stress. Fluid intake averaged 0.8 l/h during exposure (sd 0.3 l/h, range 0.3-1.5 1/h). Average urinary specific gravity at start-, mid- and end of shift was 1.0251, 1.0248 and 1.0254 respectively; the differences between start and mid-shift, mid and end-shift, and start and end-shift were not significant.However, a majority of workers were coming to work in a moderately hypohydrated state (urinary specific gravity avg 1.024, std dev 0.0059). Involuntary dehydration was not found to occur in the study group. This is in contrast to several other studies and some of the leading heat stress standards, which are based on the premise that workers are unable to maintain their hydration status when working in the heat, even when their fluid consumption is equal to their sweat rate. Continuous heart rates measured over a shift (avg 103 bpm, 14% of shifts exceeding avg 110 bpm, 5% exceeding avg 120 bpm) were in excess of those allowable under most current indices On average, workers experienced a peak 10- minute heart rate of 140 bpm and a peak 30-minute heart rate of 130 bpm during their shifts. There was a significant increase in fatigue in the first half of the working shift (P=0.001), with workers on average showing a significant recovery in the second half of their shift (p=0.04). Conclusions: Current heat stress indices provide little common agreement as to acceptable levels of thermal strain or stress for workers, at equivalent levels of environmental stress. IS07933 is seriously flawed and the ACGIH WBGT guidelines are too conservative for acclimatised workers and are unlikely to become widely adopted by industries with well-acclimatised workers. Many of the existing indices show internal inconsistencies.Most of the physiological heat strain limits used in existing rational heat stress indices (in terms of deep body core temperature and heart rate) are conservative for self-paced, acclimatise d, non-dehydrating male workers. Involuntary dehydration is not unavoidable when acclimatised workers are exposed to thermal stress. Heat stress standards should not limit heat exposure durations for self- paced workers who have access to water on the basis of an unavoidable body water loss. Physical fatigue does occur in workers under heat stress on extended shifts; however, most workers show a significant increase in fatigue in the first half of their shift; whereas data indicates self-paced workers undergo significant recovery in terms of fatigue in the second half of the shift. As the heat exposures in this study cover a wide range of temperatures, humidity levels, wind speeds, body morphology and VO2max, these conclusions are applicable to most thermally stressful settings involving well-informed, well-acclimatised and self-paced male workers. The major category of work type not covered by this study is that of workers in fully-encapsulated (vapour-barrier) protective clothing. In addition, this study examined acute effects of heat stress and strain, not effects that might only be manifest with chronic exposure to heat.
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Brake, Derrick John. "The Deep Body Core Temperatures, Physical Fatigue and Fluid Status of Thermally Stressed Workers and the Development of Thermal Work Limit as an Index of Heat Stress." Curtin University of Technology, School of Public Health, 2002. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=12353.
Повний текст джерелаАнотація:
Objectives: To determine the physiological strain on industrial workers under thermal stress on extended shifts. To continuously measure deep body core temperatures, heart rates, fluid intake, changes in hydration state and physical fatigue in order to establish acceptable levels of physiological strain. To develop a rational heat stress index compatible with these limits. To design working-in-heat protocols for a self-paced workforce. Methods: A series of studies was conducted over 77 shifts on a group of approximately 50 male volunteers working in thermally stressful environments. Continuously- recorded deep body core temperatures, heart rates, fluid consumption, urinary specific gravity and physical fatigue were measured and recorded. A new field protocol was developed to assess physical fatigue over the working shift. An original methodology was developed to allow any heat stress index to be assessed on a comparative basis with any other index. A review of the commonly used occupational heat stress indices was conducted. A new rational heat stress index was developed, based on existing biophysical relationships and recommended physiological strain limits of deep body core temperature and sweat rate. New protocols designed for self-paced work incorporating the significant risk factors for heat illness were developed and implemented in a workforce of approximately 2000 workers exposed to heat stress. The previous protocols used a shortened shift as the primary intervention to protect worker health. The subsequent protocols removed the shortened shift and replaced this with a range of other interventions. Deep body core temperature, heart rate, fluid consumption, hydration state and fatigue were measured before and after the changes in protocols.Results: Comparisons of heat stress indices confirmed the wide divergence in guidance provided by many of the commonly-used indices in terms of acceptable working environments. It also highlighted a number of serious shortcomings in the most widely-used indices, especially WBGT and ISO7933. A new, rational heat stress index called Thermal Work Limit (TWL) was developed. This included development of a computer model incorporating key thermal physiological parameters (deep body core temperature, mean skin temperature, sweat rate, skin wettedness). There was no increase in heat stress (as indicated by average workplace environmental conditions), deep body core temperature, mean heart rate, or changes in hydration status after the changes in protocols. Average environmental conditions were severe (WBGT 30.9° C, sd 2.0° C, range 25.7-35.2° C). Environmental conditions in the study were much hotter than those considered acceptable under standards such as the ACGIH. The results showed that miners regularly exceeded those limits allowable under most current indices in terms of maximum deep body core temperature (avg 38.3° C, std dev 0.4° C), maximum temperature rise (1.4° C, 0.4° C) and maximum heat storage (431 kJ, 163 kJ), without reporting any symptoms of heat illness. A significant component of the observed elevated core temperatures was due to the normal circadian rhythm, which was measured at 0.9° C (std dev 0.2° C). Evidence was found that workers "self-pace" when under thermal stress. Fluid intake averaged 0.8 l/h during exposure (sd 0.3 l/h, range 0.3-1.5 1/h). Average urinary specific gravity at start-, mid- and end of shift was 1.0251, 1.0248 and 1.0254 respectively; the differences between start and mid-shift, mid and end-shift, and start and end-shift were not significant.
However, a majority of workers were coming to work in a moderately hypohydrated state (urinary specific gravity avg 1.024, std dev 0.0059). Involuntary dehydration was not found to occur in the study group. This is in contrast to several other studies and some of the leading heat stress standards, which are based on the premise that workers are unable to maintain their hydration status when working in the heat, even when their fluid consumption is equal to their sweat rate. Continuous heart rates measured over a shift (avg 103 bpm, 14% of shifts exceeding avg 110 bpm, 5% exceeding avg 120 bpm) were in excess of those allowable under most current indices On average, workers experienced a peak 10- minute heart rate of 140 bpm and a peak 30-minute heart rate of 130 bpm during their shifts. There was a significant increase in fatigue in the first half of the working shift (P=0.001), with workers on average showing a significant recovery in the second half of their shift (p=0.04). Conclusions: Current heat stress indices provide little common agreement as to acceptable levels of thermal strain or stress for workers, at equivalent levels of environmental stress. IS07933 is seriously flawed and the ACGIH WBGT guidelines are too conservative for acclimatised workers and are unlikely to become widely adopted by industries with well-acclimatised workers. Many of the existing indices show internal inconsistencies.
Most of the physiological heat strain limits used in existing rational heat stress indices (in terms of deep body core temperature and heart rate) are conservative for self-paced, acclimatise d, non-dehydrating male workers. Involuntary dehydration is not unavoidable when acclimatised workers are exposed to thermal stress. Heat stress standards should not limit heat exposure durations for self- paced workers who have access to water on the basis of an unavoidable body water loss. Physical fatigue does occur in workers under heat stress on extended shifts; however, most workers show a significant increase in fatigue in the first half of their shift; whereas data indicates self-paced workers undergo significant recovery in terms of fatigue in the second half of the shift. As the heat exposures in this study cover a wide range of temperatures, humidity levels, wind speeds, body morphology and VO2max, these conclusions are applicable to most thermally stressful settings involving well-informed, well-acclimatised and self-paced male workers. The major category of work type not covered by this study is that of workers in fully-encapsulated (vapour-barrier) protective clothing. In addition, this study examined acute effects of heat stress and strain, not effects that might only be manifest with chronic exposure to heat.
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Ross, Megan L. "Practical precooling strategies and cycling time trial performance." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2012. https://ro.ecu.edu.au/theses/511.
Повний текст джерелаАнотація:
Whole-body precooling can improve endurance exercise performance, especially in the heat; however there are logistical considerations that restrict the use of various precooling strategies prior to actual competition. Precooling is proposed to collectively reduce deep skin and body temperature and in effect, increase the heat storage capacity of an athlete, thereby allowing a greater amount of work to be completed prior to attainment of a critical core temperature. While there is a sound theoretical basis for implementing precooling to improve cycling time trial performance in the heat, the practicalities of employing effective precooling strategies in the field warrant further investigation. The purpose of this thesis was to investigate the effectiveness of various practical precooling strategies for reducing core temperature and improving cycling time trial performance in hot (32-35ºC; 50-60% r.h.) and temperate (20-22 ºC; 50-60% r.h.) conditions.
The first three studies of this thesis involved the manipulation of body temperature via a range of precooling strategies that were applied under hot and humid environmental conditions. In study 1, eight precooling strategies involving external application or internal ingestion of cold water and ice were evaluated for their effectiveness in lowering deep body temperature, with due consideration regarding their application in a practical setting. The novel strategy identified in this study, which involved the combined application of iced towels and ingestion of an ice-slurry (“slushie”) made from sports drink, was then compared with an established cooling strategy (Study 2). Both the new and established precooling strategies achieved noticeable cooling effects (moderate and very large, respectively) but only the new strategy enhanced mean power output (3%, 8W) during a 46.4 km laboratory-based cycling protocol, with performance improvements detected in the second half of the time trial. This strategy was also found to be practical to implement. In study 3, practical precooling and hyperhydration were evaluated to assess whether their combination offered further benefits to endurance cycling time trial performance, when assessed over the same laboroatory protocol. The main findings indicated that practical precooling and hyperhydration, with and without the co-ingestion of glycerol, failed to achieve a clear enhancement of cycling performance. However, when practical precooling and hyperhydration without glycerol was compared to the control condition (i.e., hyperhydration alone), there was a 2% (30 s) improvement in cycling performance time, which was detected in the second half (climb 2) of the time trial. These improvements may be partially explained by a lower percieved exertion, which was observed during the initial 10 km of the time trial.
Study 4 was conducted to validate anecdotal reports and laboratory-based observations of thermoregulatory strain in elite cyclists during a real-life event performed in temperate environmental conditions. The rationale for this study was to determine whether the magnitude of hyperthermia achieved during real-life cycling performed in temperate conditions was high enough to possibly benefit from precooling. Although fluid losses during racing were mild (1.3%), cyclists experienced hyperthermia, at magnitudes typically associated with heat-stress induced fatigue (>67% of observations). Therefore, in the final study of this thesis, the effects of practical precooling on 45.6 km cycling time trial performance was examined in both hot (32˚C) and temperate (21˚C) environmental conditions. The effectiveness of practical precooling was enhanced in temperate conditions, such that there was a greater magnitude of body cooling achieved. However, this strategy failed to provide a clear performance benefit in temperate conditions and instead, was likely to impair performance, particularly in the first (flat) section of the time trial course (-2.3%, 8 W).
Collectively, the studies contained within this thesis have contributed to the development of a practical precooling strategy involving the combined application of iced towels and ingestion of a slushie made from sports drink. These studies confirm the effectiveness of this novel strategy in reducing skin and core temperature and enhancing heat storage capacity prior to the commencement of exercise. However, the associated reduction in thermoregulatory strain translates into a performance enhancement in hot, but not temperate conditions. This thesis has provided detailed information regarding the range of factors that may be involved in altering the efficacy of a precooling manoeuvre and offers a highly practical insight into the application of precooling strategies aimed at improving field-based sports performance specific to time trial cycling.
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Petit, Élisabeth. "Effets d'un décalage horaire "simulé" et d'une sieste sur les performances physiques et psychomotrices du sportif." Thesis, Besançon, 2013. http://www.theses.fr/2013BESA0007.
Повний текст джерелаАнотація:
Résumé : Chez le sportif, le franchissement de plusieurs fuseaux horaires avec décalage horaire s'accompagne d'une fatigue avec somnolence diurne, d'une diminution des performances cognitives, sportives et de la vigilance. Une sieste de courte durée pourrait être une solution adaptée pour prévenir les effets du jet lag. A notre connaissance, aucune étude n'a évalué les effets d'une sieste et/ou les effets combinés du décalage horaire et d'une sieste sur les performances des athlètes.C'est pourquoi, l'objectif de cette thèse est d'étudier chez des athlètes, les effets d'une avance de phase de 5 heures (simulant un voyage transméridien vers l'Est) et d'une sieste post-prandiale de 20 minutes sur les réponses à un exercice physique de courte durée et à des tâches psychomotrices ainsi que sur le sommeil subséquent. Seize sujets jeunes, sains, de sexe masculin et sportifs (âge : 22.2 ± 1.7 ans ; taille : 178.3 ± 5.6 cm, poids : 73,6 ± 7,9 kg ; VC>2 max : 55.5 ± 9,1 ml.min.kg"' ; siesteurs non habituels) ont participé à cette étude. Aucun ne présentait de pathologie du sommeil. Chaque sujet a passé en laboratoire une nuit d'habituation et 8 nuits expérimentales dont 4 en condition normale (23H-7H, 2 nuits pré-tests et 2 post-tests) et 4 en avance de phase de 5 h ( 18H-2H, 2 nuits pré et 2 post-tests) avec enregistrement EEG continu. Après un repas standardisé au laboratoire, les sujets ont été soumis, entre 13 et 14H (condition normale), et entre 08 et 09H (condition de décalage), soit à une sieste (20 min de sommeil), soit à une période de repos en décubitus sans sommeil. A l'issue, les sujets ont réalisé un test de performance attentionnelle, évaluant 6 champs de l'attention, un test de Handgrip et un test Wingate avec mesure de la lactatémie en fin d'exercice et lors de la récupération. Ces mêmes tests ont été reconduits 2 heures plus tard dans le même ordre. La température rectale a été enregistrée par holter tout au long de la période expérimentale.Les résultats montrent que le décalage horaire modifie l'architecture du sommeil de la nuit pré tests avec un déficit de sommeil d"lh20, se traduisant par une moindre efficacité de sommeil. En revanche, ce décalage améliore la qualité du sommeil de la nuit subséquente (post-tests) avec une augmentation de la quantité du N3 et du sommeil paradoxal. Une baisse significative de l'amplitude de la température interne témoigne d'un réajustement actif des sujets. L'architecture de la sieste (stades 2 et 3) est similaire qu'elle ait lieu après une nuit normale ou après décalage horaire avec toutefois une quantité de SP qui tend à augmenter après la nuit en avance de phase. Elle n'a pas d'effets sur la composition du sommeil qui suit (condition normale ou en décalage), en dehors d'une augmentation de la latence d'endormissement en condition de décalagePurpose T he aim of thé study vvas to examine thé effects of a post-prandial 20 min nap on a short-term physicalexercise and subséquent sleep in athlètes keeping their usual sleep schedules and in 5-h phase-advance condition.Methods Sixteen healthy young mâle athlètes (âge 22.2 ± 1.7 years. non-habitual nappers) participated in thé study.After a baseline 8-h time in bed in normal and 5-h advanced sleep schedules, a standardized moming and lunch in alaboratory enviromnent, subjects undervvent either a nap (20 min of sleep elapsed from 3 epochs of stage 1 or 1 epochof stage 2), or a rest without sleep by lying in a bed, between 13:00 and 14:00 hours in non-shifted condition or 08:00and 09:00 hours in shifted condition, after vvhich anaerobic exercises were perforrned tvvice 2 h apart. Core bodytempérature vvas recorded throughout thé study period.Resuhs The nap extended sleep onset latency from6.72 ± 3.83 to 11.84 ± 13.44 min, after shifted condition but did not modify sleep architecture of thé post-trial nightamong athlètes, vvhether shifted or not. Moreover, napping did not improve physical performance but it delayedacrophase and batyphase of core body température rhythm pararneters.Conclusion N apping showed no reliable benefit on short-term performances of athlètes exercising at local time or aftera simulated jet lag
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Wilsmore, Bradley R. "Thermoregulation in people with spinal cord injury." School of Health Sciences - Faculty of Health and Behavioural Sciences, 2007. http://ro.uow.edu.au/theses/85.
Повний текст джерелаАнотація:
Thermoafferent information is integrated at multiple levels within the central nervous system. However, due to the difficulty in differentiating thermoregulatory functions of the spinal cord from those of higher centres in humans, the role of the spinal cord in certain aspects of thermoregulation remains unclear. Subjects with spinal cord injury have unique neural changes providing an opportunity to evaluate the role of the spinal cord, independently of higher thermoregulatory centres. Subjects with (N=11) and without (N=11) spinal cord injury were studied in a series of experiments, in which a wide range of local and whole-body temperature changes and postural manipulations were imposed. During these trials, various physiological (skin temperature, core temperature, local sweat rate and sweat expulsion frequency - a measure of central sympathetic drive), and psychophysical variables (thermal sensation and discomfort) were investigated. Six key observations arose from these experiments: (i) Subjects with spinal cord injury had a lower thermoafferent capacity (secondary to neural damage) and a corresponding reduction in thermoefferent drive (sudomotor sensitivity of 4.2 versus 8.8 expulsions•min-1•C-1 in able-bodied; P=0.03). (ii) Equations used to approximate thermoafferent drive in able-bodied subjects, overestimated thermal feedback in subjects with spinal cord injury. However, this could be corrected by modifying the skin area weightings to include only the sensate areas. (iii) No subjects with physiologically-confirmed thermoefferent spinal cord injury displayed sweating from insensate skin sites, indicating that a spinal cord that has been isolated from higher centres cannot induce thermal sweating. (iv) Subjects with spinal cord injury had higher forehead sweat rates (0.77 versus 0.52 mg•cm-2•min-1; P=0.03), but an equivalent sweat sensitivity (1.24 versus 1.27 mg•cm-2•min-1•°C-1; P=0.94), indicating the presence of a peripheral adaptation to sustain thermal homeostasis, and secondary to reduced thermal afferent and efferent flow. (v) Respiratory frequency increased more for a given increase in body temperature in subjects with spinal cord injury (2.4 versus 1.1 breaths•min-1•°C-1; P=0.042), but this did not provide a thermoregulatory benefit. (vi) Subjects with spinal cord injury demonstrated greater changes in behavioural thermoregulatory indicators (thermal sensation and discomfort) in response to standardised local and whole-body thermal loads. Collectively, these observations indicate the unique nature of thermoregulation in people with spinal cord injury and the adaptive ability of the human thermoregulatory system.
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Cham, Joo Lee, and julie cham@rmit edu au. "The role of the hypothalamic paraventricular nucleus in the cardiovascular responses to elevations in body temperature." RMIT University. Medical Sciences, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080805.114529.
Повний текст джерелаАнотація:
The hypothalamic paraventricular nucleus (PVN) is known to be a major integrative region within the forebrain. It is composed of functionally different subgroups of neurons, including the parvocellular neurons that project to important autonomic targets in the brainstem e.g. the rostral ventrolateral medulla (RVLM) and the intermediolateral cell column (IML) of the spinal cord, where the sympathetic preganglionic motor-neurons are located. These regions are critical in cardiovascular regulation; hence, these projections are likely to mediate the effects of the PVN on sympathetic nerve activity and hence may contribute to the cardiovascular changes induced by physiological stimuli such as elevations in body temperature. The neurotransmitter such as nitric oxide (NO) is important in cardiovascular regulation and it is now emerging as a major focus of investigation in thermoregulation. One of the most striking accumulations of NO containing-neurons is in the PVN where it appears to be playing an important role in cardiovascular regulation and body fluid homeostasis. The results of the work show; 1. That spinally-projecting and nitrergic neurons in the PVN may contribute to the central pathways activated by exposure to a hot environment. 2. Suggests that nitrergic neurons and spinally- projecting neurons in the brainstem may make a small contribution to the central pathways mediating the reflex responses initiated by hyperthermia. 3. The present study also illustrates that these PVN neurons projecting to the RVLM may make a smaller contribution than the spinal-projecting neurons in the PVN to the cardiovascular responses initiated by heat. 4. The results of my studies showed that the microinjection of muscimol to inhibit the neuronal activity in the PVN abolished the reflex decrease in renal blood flow following an elevation of core body temperature. In addition, this effect was specific to the PVN, since microinjections of muscimol into areas outside the PVN were not effective. These findings demonstrate that the PVN is critical for this reflex cardiovascular response initiated by hyperthermia. In conclusion, PVN is critical for the reflex decrease in renal blood flow during elevations in core body temperature. We hypothesise that projections from the PVN to the spinal cord and the RVLM contribute to the reflex cardiovascular responses. Additionally, nitrergic neurons in the PVN may contribute but the physiological role of those neurons in the reflex responses elicited by hyperthermia needs to be investigated.
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Nascimento, Sheila Tavares. "Determinação do balanço de calor em frangos de corte por meio das temperaturas corporais." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11131/tde-29112010-091752/.
Повний текст джерелаАнотація:
O objetivo desta pesquisa foi avaliar o comportamento térmico de diferentes linhagens de frangos de corte submetidas a estresse e conforto durante o ciclo de produção. Para isso, realizou-se um experimento em câmara climática, durante as seis semanas do ciclo de criação, em que os animais foram submetidos a duas condições ambientais: conforto e estresse. Foram adotados quatro tratamentos, sendo assim definidos: tratamento C60 (condição de conforto), com 60 minutos de exposição; tratamento E30, tratamento E60 e tratamento E90 (condição de estresse), com 30, 60 e 90 minutos de exposição, respectivamente. O delineamento experimental adotado foi o de quadrados latinos 4 x 4, sendo caracterizados por quatro lotes de aves, expostas aos quatro tratamentos, nos quatro primeiros dias de cada semana. As aves, das linhagens Avian e Cobb, foram divididas em lotes de 48 aves por semana, totalizando 96 animais, e totalizando 586 aves, de ambos os sexos, durante todo o período experimental. As variáveis climáticas adotadas para as condições de conforto e estresse diferiram ao longo das semanas, uma vez que as necessidades térmicas de frangos de corte diferem com o decorrer do ciclo produtivo. No primeiro capítulo, as variáveis fisiológicas, frequência respiratória e temperatura cloacal foram estudadas, estipulando-se, dessa maneira, faixas para as condições de conforto e estresse. Com base nessas variáveis, estudou-se a tolerância das linhagens ao estresse térmico, e observou-se que a linhagem Cobb é mais tolerante ao estresse térmico. No segundo capítulo, estudou-se a influência de tempo de exposição sobre a temperatura superficial das seguintes regiões corporais: asa, cabeça, pata, dorso e crista. O tempo de exposição não influenciou, em nenhuma das semanas, a temperatura superficial das aves, havendo diferenças significativas apenas entre a condição de conforto e estresse. Baseando-se nessas informações, e nessas regiões corporais, determinaram-se modelos de regressão linear múltipla para cada uma das semanas do ciclo de criação, para ambas as linhagens, sendo denominadas por TSM Nascimento. A escolha dos modelos foi realizada pelo método da máxima verossimilhança, pelo critério de Akaike (AIC) e pelo teste qui-quadrado para verificar o número de regiões corporais incluídas em cada um dos distintos modelos. No terceiro capítulo, efetuou-se o balanço de calor sensível e latente das aves, baseado nos modelos de temperatura superficial TSM Nascimento, na temperatura do núcleo corporal (adotada na pesquisa como a temperatura cloacal) e nas variáveis ambientais coletadas durante a pesquisa, para ambas as linhagens. Observou-se que, em condição de conforto, a partir da terceira semana, as trocas sensíveis correspondem a até 80% do total das trocas de calor. Em estresse térmico, as trocas latentes correspondem a até 84% do total. Verificou-se que as aves são mais susceptíveis ao estresse térmico na terceira semana do ciclo produtivo.The aim of this research was to evaluate thermal behaviour of different broiler chicken strains submitted to stress and comfort through lifecycle. Thereunto, an experiment was accomplished in climatic chamber, during the six weeks of life of the birds, with the animals submitted to two environmental conditions: comfort and stress. Four treatments were adopted, defined as: treatment C60 (comfort condition), with 60 minutes of exposure; treatment E30, treatment E60 and treatment E90 (stress condition), with 30, 60 and 90 minutes of exposure, respectively. Experimental design adopted was a 4 x 4 latin square, characterized by four lots of birds, exposed to the four treatments, in the first four days of each week. Broiler, from Avian and Cobb strains, were divided in lots of 48 birds per week, totalizing 96 animals, and totalizing 586 animals, both sexes, during all experimental period. Climatic variables adopted to comfort and stress conditions differd through the weeks, once that thermal requirements of broiler chickens differ throughout growing cycle. In the first chapter, physiological variables respiration rate and cloacal temperature were studied, stipulating in this way, bands to comfort and stress conditions. Based on these variables, the tolerance of strains to thermal stress was studied, and was observed that Cobb strain is more tolerant to heat stress. In the second chapter, the influence of exposure time on superficial temperature was studied in the following body regions: wing, head, feet, back and comb. Exposure time did not influence, in none of weeks, superficial temperature of birds, with significative differences only among comfort and stress conditions. Based on these boards, and on these body regions, multiple linear regression models were determined to each week of lifecycle, to both strains, being named as TSM Nascimento. The selection of the models was done by maximum likelihood method, by Akaikes criteria (AIC) and by qui-square test to verify the number of body regions included in each one of the models. In the third chapter, was accomplished sensible and latent heat balance of the birds, based on superficial temperature models TSM Nascimento, core body temperature (adopted in the research as cloacal temperature) and on environmental variables collected during the research, to both strains. It was observed that in comfort condition, from third week of lifecycle and on, sensible exchanges corresponded for up to 80% of the total exchanges. In thermal stress, latent exchanges corresponded for up to 84% of the total. It was verified that broiler chickens are more susceptible to thermal stress in the third week of lifecycle.
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Mathavakkannan, Suresh. "Techniques to assess volume status and haemodynamic stability in patients on haemodialysis." Thesis, University of Hertfordshire, 2010. http://hdl.handle.net/2299/4811.
Повний текст джерелаАнотація:
Volume overload is a common feature in patients on haemodialysis (HD). This contributes significantly to the cardiovascular disease burden seen in these patients. Clinical assessments of the volume state are often inaccurate. Techniques such as interdialytic blood pressure, relative blood volume monitoring, bioimpedance are available to improve clinical effectives. However all these techniques exhibit significant shortcomings in their accuracy, reliability and applicability at the bed side. We evaluated the usefulness of a dual compartment monitoring technique using Continuous Segmental Bioimpedance Spectroscopy (CSBIS) and Relative Blood Volume (RBV) as a tool to assess hydration status and determine dry weight. We also sought to evaluate the role of Atrial Natriuretic Peptide (ANP) and B-type Natriuretic Peptide (BNP) as a volume marker in dialysis patients. The Retrospective analysis of a historical cohort (n = 376, 55 Diabetic) showed a significant reduction in post-dialysis weights in the first three months of dialysis (72.5 to 70kg, p<0.027) with a non-significant increase in weight between months 6-12. The use of anti-hypertensive agents reduced insignificantly in the first 3 months, increased marginally between months 3-6 and significantly increased over the subsequent 6 months. The residual urea clearance (KRU) fell and dialysis times increased. The cohort was very different to that dialysing at Tassin and showed a dissociation between weight reduction and BP control. This may relate to occult volume overload. CSBIS-RBV monitoring in 9 patients with pulse ultrafiltration (pulse UF) showed distinct reproducible patterns relating to extra cellular fluid (ECF) and RBV rebound. An empirical Refill Ratio was then used to define the patterns of change and this was related to the state of their hydration. A value closer to unity was consistent with the attainment of best achievable target weight. The refill ratio fell significantly between the first (earlier) and third (last) rebound phase (1.97 ± 0.92 vs 1.32 ± 0.2). CSBIS monitoring was then carried out in 31 subjects, whilst varying dialysate composition, temperature and patient posture to analyse the effects of these changes on the ECF trace and to ascertain whether any of these interventions can trigger a change in the slope of the ECF trace distinct to that caused by UF. Only, isovolemic HD caused a change in both RBV and ECF in some patients that was explained by volume re-distribution due to gravitational shifts, poor vascular reactivity, sodium gradient between plasma and dialysate and the use of vasodilating antihypertensive agents. This has not been described previously. These will need to be explored further. The study did demonstrate a significant lack of comparability of absolute values of RECF between dialysis sessions even in the same patient. This too has not been described previously. This is likely to be due to subtle changes in fluid distribution between compartments. Therefore a relative changes must be studied. This sensitivity to subtle changes may increase the usefulness of the technique for ECF tracking through dialysis. The potential of dual compartment monitoring to track volume changes in real time was further explored in 29 patients of whom 21 achieved weight reductions and were able to be restudied. The Refill Ratio decreased significantly in the 21 patients who had their dry weights reduced by 0.95 ± 1.13 kg (1.41 ± 0.25 vs 1.25 ± 0.31). Blood pressure changes did not reach statistical significance. The technique was then used to examine differences in vascular refill between a 36oC and isothermic dialysis session in 20 stable prevalent patients. Pulse UF was carried out in both these sessions. There were no significant differences in Refill Ratios, energy removed and blood pressure response between the two sessions. The core temperature (CT) of these patients was close to 36oC and administering isothermic HD did not confer any additional benefit. Mean BNP levels in 12 patients during isovolemic HD and HD with UF did not relate to volume changes. ANP concentrations fell during a dialysis session in 11 patients from a mean 249 ± 143 pg/ml (mean ± SD) at the start of dialysis to 77 ± 65 pg/ml at the end of the session (p<0.001). During isolated UF levels did not change but fell in the ensuing sham phase indicating a time lag between volume loss and decreased generation. (136±99 pg/ml to 101±77.2 pg/ml; p<0.02) In a subsequent study ANP concentrations were measured throughout dialysis and in the post-HD period for 2 hours. A rebound in ANP concentration was observed occurring at around 90 min post-HD. The degree of this rebound may reflect the prevailing fluid state and merit further study. We have shown the utility of dual compartment monitoring with CSBIS-RBV technique and its potential in assessing volume changes in real time in haemodialysis patients. We have also shown the potential of ANP as an independent marker of volume status in the same setting. Both these techniques merit further study.
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Rickelmann, Mary Ann. "Comparison of core and rectal temperature measurements a research report submitted in partial fulfillment ... medical-surgical nursing /." 1989. http://catalog.hathitrust.org/api/volumes/oclc/68788469.html.
Повний текст джерела
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Sancheti, Ajay. "The influence of human core temperature on minute ventilation /." 2002.
Знайти повний текст джерела
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Shipp, Nicholas Jon. "The impact of core temperature corrections on exercise-induced hypoxemia." 2008. http://hdl.handle.net/2440/47970.
Повний текст джерелаАнотація:
The primary purpose of this doctoral dissertation was to investigate the effect of body temperature responses at physiologically relevant sites during an incremental exercise test on the phenomenon of exercise-induced hypoxemia (EIH). This phenomenon has been considered as an important limitation to physical performance with a prevalence of ~50 % in trained male athletes, but described in both sexes, across the range of both age and physical fitness in more recent literature. Previously this phenomenon has been described as a decrement in both arterial oxygen partial pressure (PaO₂) and oxy-haemoglobin saturation (SaO₂or SpO₂) with, particularly important for PaO₂, a lack of or inappropriate correction made for the change in body temperature during intense exercise. The initial study of this thesis determined the thermal response within the body at physiologically relevant sites measured simultaneously during an incremental exercise test. The results demonstrated the inadequacy of rectal temperature as an indicator of the acute temperature changes occurring during an incremental exercise test due to its slow response rate and relative thermal inertia. Radial arterial blood and oesophageal temperatures were shown to behave almost identically during the exercise test, albeit with an offset of approximately 1.3ºC, and were considered much more appropriate and relevant indicators of thermal changes during exercise. As an extension of the initial work active muscle temperature (vastus lateralis) was measured during the exercise test, demonstrating a significantly lower resting temperature than the oft-reported “core” temperatures (rectal and oesophageal) as well as a significantly greater increase in temperature in comparison to all other measurement sites. Overall, the results of this first study indicated that the physiologically relevant temperatures measured at the oesophageal and muscle sites differed markedly to the outdated rectal temperature measurement site and should be used as measures of thermal response when evaluating oxygen loading (oesophageal) or unloading (active muscle). Utilising the definition of EIH as a decrease in PaO₂ of ≥ 10 mmHg, the effect of temperature correcting PaO₂ was evaluated in the second study. Arterial blood gases measured simultaneously to the temperature measurements during the incremental exercise test were adjusted for the temperature changes at each site (every 1ºC increase in temperature will increase a PaO₂ value by ~5 mmHg). Whilst uncorrected PaO₂ values indicated an almost 100% prevalence of EIH in this group, oesophageal temperature corrected PaO₂ values decreased this prevalence to ~50% while muscle temperature corrections resolved all cases of EIH and demonstrated an HYPEROXAEMIA (i.e. the reverse of the well-established phenomenon) in the majority of subjects. Further investigation of arterial oxygen content during the exercise test indicates that there is no disruption in the delivery of oxygen to the active muscles and therefore any performance decrement should be attributed to another mechanism. Whilst the phenomenon of EIH is determined by the definition applied and the use of temperature corrections in the case of PaO₂, its reproducibility in a test-retest situation had not previously been determined. Utilising a subset of previously tested subjects, the reproducibility of both temperature and PaO₂ were determined with results indicating that the blood gas response was highly reproducible, especially the minimum PaO₂ value noted during each exercise test. However, comparing a more statistically relevant definition of a change in PaO₂ of ± 2 standard deviations from the mean resting PaO₂ to the previous delimiter of 10 mmHg indicated a lesser reproducibility of the prevalence of EIH. In summary, this thesis exposes the inadequacies of previous research into EIH with regard to the expected reproducibility of the phenomenon and the need to correctly adjust PaO₂ values for exercise-induce hyperthermia as well as demonstrating the difference in thermal responses to acute exercise in physiologically significant areas of the body. Furthermore, previously described correlations between the change in PaO₂ and VO₂ max were not evident in the subjects tested within this thesis, nor was there any indication of a diffusion limitation based on reduced pulmonary capillary transit time (by association with VO₂ max) or pulmonary oedema (rebuked by a rapid return of PaO₂ to above resting levels following exercise cessation).http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320633
Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008
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Shipp, Nicholas Jon. "The impact of core temperature corrections on exercise-induced hypoxemia." Thesis, 2008. http://hdl.handle.net/2440/47970.
Повний текст джерелаАнотація:
The primary purpose of this doctoral dissertation was to investigate the effect of body temperature responses at physiologically relevant sites during an incremental exercise test on the phenomenon of exercise-induced hypoxemia (EIH). This phenomenon has been considered as an important limitation to physical performance with a prevalence of ~50 % in trained male athletes, but described in both sexes, across the range of both age and physical fitness in more recent literature. Previously this phenomenon has been described as a decrement in both arterial oxygen partial pressure (PaO₂) and oxy-haemoglobin saturation (SaO₂or SpO₂) with, particularly important for PaO₂, a lack of or inappropriate correction made for the change in body temperature during intense exercise.
The initial study of this thesis determined the thermal response within the body at physiologically relevant sites measured simultaneously during an incremental exercise test. The results demonstrated the inadequacy of rectal temperature as an indicator of the acute temperature changes occurring during an incremental exercise test due to its slow response rate and relative thermal inertia. Radial arterial blood and oesophageal temperatures were shown to behave almost identically during the exercise test, albeit with an offset of approximately 1.3ºC, and were considered much more appropriate and relevant indicators of thermal changes during exercise. As an extension of the initial work active muscle temperature (vastus lateralis) was measured during the exercise test, demonstrating a significantly lower resting temperature than the oft-reported “core” temperatures (rectal and oesophageal) as well as a significantly greater increase in temperature in comparison to all other measurement sites. Overall, the results of this first study indicated that the physiologically relevant temperatures measured at the oesophageal and muscle sites differed markedly to the outdated rectal temperature measurement site and should be used as measures of thermal response when evaluating oxygen loading (oesophageal) or unloading (active muscle).
Utilising the definition of EIH as a decrease in PaO₂ of ≥ 10 mmHg, the effect of temperature correcting PaO₂ was evaluated in the second study. Arterial blood gases measured simultaneously to the temperature measurements during the incremental exercise test were adjusted for the temperature changes at each site (every 1ºC increase in temperature will increase a PaO₂ value by ~5 mmHg). Whilst uncorrected PaO₂ values indicated an almost 100% prevalence of EIH in this group, oesophageal temperature corrected PaO₂ values decreased this prevalence to ~50% while muscle temperature corrections resolved all cases of EIH and demonstrated an HYPEROXAEMIA (i.e. the reverse of the well-established phenomenon) in the majority of subjects. Further investigation of arterial oxygen content during the exercise test indicates that there is no disruption in the delivery of oxygen to the active muscles and therefore any performance decrement should be attributed to another mechanism.
Whilst the phenomenon of EIH is determined by the definition applied and the use of temperature corrections in the case of PaO₂, its reproducibility in a test-retest situation had not previously been determined. Utilising a subset of previously tested subjects, the reproducibility of both temperature and PaO₂ were determined with results indicating that the blood gas response was highly reproducible, especially the minimum PaO₂ value noted during each exercise test. However, comparing a more statistically relevant definition of a change in PaO₂ of ± 2 standard deviations from the mean resting PaO₂ to the previous delimiter of 10 mmHg indicated a lesser reproducibility of the prevalence of EIH.
In summary, this thesis exposes the inadequacies of previous research into EIH with regard to the expected reproducibility of the phenomenon and the need to correctly adjust PaO₂ values for exercise-induce hyperthermia as well as demonstrating the difference in thermal responses to acute exercise in physiologically significant areas of the body. Furthermore, previously described correlations between the change in PaO₂ and VO₂ max were not evident in the subjects tested within this thesis, nor was there any indication of a diffusion limitation based on reduced pulmonary capillary transit time (by association with VO₂ max) or pulmonary oedema (rebuked by a rapid return of PaO₂ to above resting levels following exercise cessation).Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2008
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Pretorius, Dorathea. "Whole head submersion and its effect on the rate of cooling of body core temperature." 2005. http://hdl.handle.net/1993/20187.
Повний текст джерела
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"TRAILER MICRO-CLIMATE DURING LONG-DISTANCE TRANSPORT OF FINISHED BEEF CATTLE FOR THE SUMMER MONTHS IN NORTH AMERICA." Thesis, 2013. http://hdl.handle.net/10388/ETD-2013-12-1378.
Повний текст джерелаАнотація:
Transporting cattle from southern Alberta into the United States (US) plays a substantial economic role in the western Canadian beef industry. Thermal environments within cattle transport trailers are dependent on ambient conditions, and if inadequately managed, can be a welfare concern. To effectively manage cattle transport, the environmental conditions throughout the livestock trailer must be understood. The objective of the present study was to investigate the trailer micro-climate and welfare during 5-paired commercial long-haul transports of slaughter cattle from Alberta, Canada to Washington State, US during summer months. In addition, the effect of compartment location and trailer porosity (8.7% vs 9.6%) on trailer micro-climate, shrink and core body temperature were also investigated during the warmest in-transit hour and stationary events. The compartment location had an effect on micro-climate variables where the upper compartment had greater (P < 0.05) temperature than the bottom deck compartments and relative humidity variables had the opposite effect for both the warmest in-transit hour and stationary events. There was also an effect of trailer porosity on micro-climate variables where it was generally warmer in the trailer with the higher porosity in the stationary event. Differences between trailers included 2 additional roof hatches on the trailer with lower side-wall porosity and lower internal temperatures, which could suggest the location of the trailer porosity, could be important for heat and moisture exchange during transit. The nose of the trailer with higher porosity had generally warmer internal conditions (larger T(trailer)°C and THI(trailer)) than the trailer with lower porosity. This study also found that the temperatures inside the trailer can be 10.5°C greater than ambient temperatures during stationary events and 9°C greater than ambient levels during the warmest in-transit hour. The average amount of per-animal weight loss was 4.3 0.3 % and was affected by trailer porosity and compartment, which followed the trends in thermal environment variables. The transit status (stationary or in-transit) and trailer porosity affected the vaginal core body temperature of the heifers in transit. The core body temperature was greater during stationary events for animals transported in the trailer with lower porosity. It is suggested that the lower side-wall porosity and/or the shape of perforation pattern could impair the movement of fresh air to the respiratory tract of heifers, thus impacting the main mechanism for dissipating heat. The difference in temperature from the trailer ceiling to the animal level was 3.38°C in the trailer with lower porosity (cooler at the ceiling) and 2.23°C in the trailer with the higher porosity. This relationship also had a compartment location effect that followed the micro-climate compartmental differences. This could suggest that excess heat in the trailer with the lower porosity, that also had lower overall temperatures, exited through roof hatches, while in the trailer with the higher porosity, the heat escaped through the side-wall perforations. This theory also supports the idea that the location of where the porosity is located on the trailer may be important to alleviating heat stress in summer months during transport. The results of this study also indicated that there was no difference in the location of the data logger plane (driver, middle passenger) and within the compartments (front, middle, back), suggesting that compartment location effect is substantial when considering micro-climate but temperatures within a compartment are mostly homogenous. The trip that had average ambient temperatures of 25.9 ± 6.06°C for the entire journey, had a temperature Humidity Index that was considered in the danger or emergency category according to the Livestock Weather Heat Index during 95% of the warmest in-transit hour. This suggests that during ambient temperatures of 25.9°C, both trailers used in this study did not have sufficient heat exchange to mitigate the risk of heat stress for cattle.