Experimental and Mathematical Analysis of Human Thermoregulatory Response to Cold Exposure PDF Download
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Author: Gary N. Byrd
Publisher:
ISBN:
Category : Cold
Languages : en
Pages : 236
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Book Description
Author: Gary N. Byrd
Publisher:
ISBN:
Category : Cold
Languages : en
Pages : 236
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Book Description
Author: Peter Tikuisis
Publisher:
ISBN:
Category :
Languages : en
Pages : 7
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Book Description
A multi-compartmental mathematical model for predicting human thermoregulatory responses was applied to immersion in moderately cold water. Data wer4e used from experiments where eight healthy male volunteers were used from experiments where eight healthy male volunteers were immersed nude and up to the neck for 1 h in water at 20 and 24c under conditions of rest and exercise. Rectal temperature and metabolic rate were measured before and during immersion. Once agreement between the model prediction and experimental observation was obtained, the model was used for prediction beyond the duration of the experiment. Stabilization of core temperature was predicted after 4-5 h of immersion for rest and after 2-4 for exercise. Stabilization for resting individuals has been observed in other experiments under similar conditions. These results suggest that linear extrapolations based on linear body cooling rates are inadequate for predicting endurance times in moderately cold water, In this study, predicted endurance times were based on the concept of relative exercise intensity and are in agreement with the limited data available. Keywords: Tolerances (Physiology), Body temperature, Reprints. (sdw).
Author: Peter Tikuisis
Publisher:
ISBN:
Category :
Languages : en
Pages : 35
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Book Description
A mathematical model of thermoregulation has been developed to simulate human physiological responses to cold-water immersion. Data were obtained from experiments where thirteen healthy male volunteers were totally immersed under resting and nude conditions for 1 h in water temperatures of 20 and 28 C. Mean measured rectal temperature (T sub re) fell by about 0.9 and 0.5 C in 20 and 28 C water for all subjects, yet mean measured metabolic rate (M) rose by about 275 and 90 W for the lean mass group (n=7) and 195 and 45 W for the normal mass group (n=6). To predict the observed T sub re and M values, the present model differed from its predecessors by a) determining a thermally neutral body temperature profile such that the measured and predicted initial values of T sub re and M were matched, b) including thermal inputs for shivering from the skin independent of their inclusion with the central temperature to account for the observed initial rapid rise in M, c) confining the initial shivering to the trunk region to avoid an overly large predicted initial rate of rectal cooling, and d) calculating the steady state of convective heat loss by assuming a zero rate of heat storage in the skin compartment.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 5
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Book Description
Due to low heat conductivity of body tissue, head surface cooling methods for management of the brain temperature during medical treatments often have limited utility. As blood flow rates and surface-to-volume ratios are generally high in the extremities, heat exchange between the body and the environment through the extremities is an important path for heat exchange. This study examines the effects of cold-water extremity immersion on brain temperature by simulation modeling. The work is based on a six-cylinder thermoregulatory model that predicts human thermoregulatory responses to heat, cold, and water immersion. An arteriovenous anastomosis (AVA) response algorithm was added to the base model. Arteriovenous anastomoses are assumed to be controlled by a combination of core and skin temperatures. Our series of simulation scenarios consists of resting in a hot environment (40 degrees C, 75% relative humidity) until the brain temperature rises to 39 degrees C, then continuing the rest for 1 h under one of the following treatments: (A) no cooling; (B) hands immersed in 10 degrees C; (C) feet immersed in 10 degrees C water; (D) hands/feet immersed in 10 degrees C water. The simulation results indicate that within the first 30 min, the hands, feet, or hands/feet immersion cooling resulted in brain temperature drops of 1.7 degrees C, 2.4 degrees C, and 3.3 degrees C, respectively, which correspond to cooling rates of 0.03 degrees C/min, 0.04 degrees C/min, and 0.05 degrees C/min. The predicted values show that extremity immersion cooling is a viable mechanism for simple and effective control of brain temperature.
Author: Institute of Medicine
Publisher: National Academies Press
ISBN: 0309175593
Category : Medical
Languages : en
Pages : 584
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Book Description
This book reviews the research pertaining to nutrient requirements for working in cold or in high-altitude environments and states recommendations regarding the application of this information to military operational rations. It addresses whether, aside from increased energy demands, cold or high-altitude environments elicit an increased demand or requirement for specific nutrients, and whether performance in cold or high-altitude environments can be enhanced by the provision of increased amounts of specific nutrients.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
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Book Description
A mathematical model for predicting shivering and thermoregulatory responses during long term cold exposure has been developed and validated. The basis for this model is a six-cylinder mathematical model of human temperature regulation which was well validated (Xu and Werner, Appl. Human Sci. 16:61-75, 1997) for dynamic conditions: incorporating heat, cold (less than 2 hours), clothing systems, and exercise. To what extent shivering is maintained over a long duration is not clearly known and a modeling technique has been sought to predict such responses.
Author:
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 1364
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Book Description
Author: Claus Jessen
Publisher: Springer Science & Business Media
ISBN: 3642594611
Category : Science
Languages : en
Pages : 202
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Book Description
How do mammals manage to maintain their body temperature within the same narrow range in environments as different as polar regions and hot deserts? This advanced text describes the morphological features and physiological mechanisms by which humans and other mammals maintain their body temperature within a narrow range despite large variations in climatic conditions and internal heat production. Its 19 chapters deal with the physics of heat exchange with the environment, and the autonomic and behavioural mechanisms available to control the loss and production of heat. The neuronal basis of temperature regulation and current concepts of the central nervous interface between temperature signals generated in the body and control mechanisms are examined in detail. This book is of invaluable help for undergraduates, postgraduates, teachers, physicians and scientists.
Author: R.C. Eberhart
Publisher: Springer Science & Business Media
ISBN: 1468482858
Category : Science
Languages : en
Pages : 453
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Book Description
Author: Institute of Medicine
Publisher: National Academies Press
ISBN: 0309172764
Category : Medical
Languages : en
Pages : 303
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Book Description
The activities of the Food and Nutrition Board's Committee on Military Nutrition Research (CMNR, the committee) have been supported since 1994 by grant DAMD17-94-J-4046 from the U.S. Army Medical Research and Materiel Command (USAMRMC). This report fulfills the final reporting requirement of the grant, and presents a summary of activities for the grant period from December 1, 1994 through May 31, 1999. During this grant period, the CMNR has met from three to six times each year in response to issues that are brought to the committee through the Military Nutrition and Biochemistry Division of the U.S. Army Research Institute of Environmental Medicine at Natick, Massachusetts, and the Military Operational Medicine Program of USAMRMC at Fort Detrick, Maryland. The CMNR has submitted five workshop reports (plus two preliminary reports), including one that is a joint project with the Subcommittee on Body Composition, Nutrition, and Health of Military Women; three letter reports, and one brief report, all with recommendations, to the Commander, U.S. Army Medical Research and Materiel Command, since September 1995 and has a brief report currently in preparation. These reports are summarized in the following activity report with synopses of additional topics for which reports were deferred pending completion of military research in progress. This activity report includes as appendixes the conclusions and recommendations from the nine reports and has been prepared in a fashion to allow rapid access to committee recommendations on the topics covered over the time period.
