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Results 351 - 400 of 1087
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Leon Lisa R - - 2005
Previous animal models of heat stress have been compromised by methodologies, such as restraint and anesthesia, that have confounded our understanding of the core temperature (T(c)) responses elicited by heat stress. Using biotelemetry, we developed a heat stress model to examine T(c) responses in conscious, unrestrained C57BL/6J male mice. Before ...
Wong Y T - - 2004
BACKGROUND: Carbon dioxide (CO(2)) is the most common gas used for insufflation in laparoscopy, but its effects on peritoneal physiology are poorly understood. This study looks at the changes in peritoneal and bowel serosal pH during CO(2) pneumoperitoneum, and whether heating and humidification with or without bicarbonate alters the outcomes. ...
Wells P B - - 2004
Most soft tissues that are treated clinically via heating experience multiaxial states of stress and strain in vivo and are subject to complex constraints during treatment. Remarkably, however, there are no prior data on changes in the multiaxial mechanical behavior of a collagenous tissue subjected to isometric constraints during heating. ...
Kilduff L P - - 2004
The effects of creatine (Cr) supplementation on cardiovascular, metabolic, and thermoregulatory responses, and on the capacity of trained humans to perform prolonged exercise in the heat was examined. Endurance-trained males (n = 21) performed 2 constant-load exercise tests to exhaustion at 63 +/- 5 % VO(2max) in the heat (ambient ...
Von Duvillard Serge P - - 2004
Numerous studies have confirmed that performance can be impaired when athletes are dehydrated. Endurance athletes should drink beverages containing carbohydrate and electrolyte during and after training or competition. Carbohydrates (sugars) favor consumption and Na(+) favors retention of water. Drinking during competition is desirable compared with fluid ingestion after or before ...
Wingo Jonathan E. - - 2004
OBJECTIVE: To determine if pre-exercise hydration with and without glycerol differentially affects physiologic and performance responses during mountain-bike races in the heat. DESIGN AND SETTING: Testing (random, crossover, double-blind design) included the following 3 treatments administered in conjunction with a 30-mile mountain-bike race consisting of three 10-mile (16-km) loops: (1) ...
Wilson Thad E - - 2004
Both heat stress and vestibular activation alter autonomic responses; however, the interaction of these two sympathetic activators is unknown. To determine the effect of heat stress on the vestibulosympathetic reflex, eight subjects performed static head-down rotation (HDR) during normothermia and whole body heating. Muscle sympathetic nerve activity (MSNA; peroneal microneurography), ...
Heled Yuval - - 2004
BACKGROUND: While wearing impermeable nuclear, biological, and chemical (NBC) clothing, reduction of thermal stress is of primary importance. We compared the effect between two cooling methods on the attenuation of heat strain. METHODS: There were six male subjects who were divided into two groups of three and exposed on two ...
Wallace Lance A - - 2004
Cooking, particularly frying, is an important source of particles indoors. Few studies have measured a full range of particle sizes, including ultrafine particles, produced during cooking. In this study, semicontinuous instruments with fine size discriminating ability were used to calculate particle counts in 124 size bins from 0.01 to 2.5 ...
Zaar Morten - - 2004
Reptiles are ectothermic, but regulate body temperatures (T(b)) by behavioural and physiological means. Body temperature has profound effects on virtually all physiological functions. It is well known that heating occurs faster than cooling, which seems to correlate with changes in cutaneous perfusion. Increased cutaneous perfusion, and hence elevated cardiac output, ...
Ribeiro G A - - 2004
Hydration is recommended in order to decrease the overload on the cardiovascular system when healthy individuals exercise, mainly in the heat. To date, no criteria have been established for hydration for hypertensive (HY) individuals during exercise in a hot environment. Eight male HY volunteers without another medical problem and 8 ...
Ogino J - - 2004
Idiopathic acquired generalized anhidrosis is a very rare disease of unknown pathogenesis. We report a 25-year-old man with acquired generalized anhidrosis due to occlusion of the coiled ducts. He did not have sweat secretion over the entire surface of the body, including the palms and soles. Sweat-inducing stimuli provoked tingling ...
Lawson D Scott - - 2004
In mid 2002, surveys of active extracorporeal membrane oxygenation (ECMO) centers in the United States and Canada were conducted via E-mail regarding neonatal equipment and personnel. Seventy-four out of 99 (75%) North American ECMO centers listed in the Extracorporeal Life Support Organization (ELSO) directory responded to the survey. Of the ...
Maresh C M - - 2004
During exercise-heat stress, ad libitum drinking frequently fails to match sweat output, resulting in deleterious changes in hormonal, circulatory, thermoregulatory, and psychological status. This condition, known as voluntary dehydration, is largely based on perceived thirst. To examine the role of preexercise dehydration on thirst and drinking during exercise-heat stress, 10 ...
Heled Yuval - - 2004
We hypothesized that there is an association between the angiotensin I-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism with the variability in exercise heat tolerance in humans. Fifty-eight Caucasian men were exposed to a 2-h exercise heat-tolerance test. We analyzed the association between their heat-tolerance levels with the ACE DD (n ...
Walsh Neil P - - 2004
OBJECTIVE: To identify whether saliva flow rate, total protein concentration and osmolality are sensitive non-invasive markers of whole body hydration status, we compared changes in these parameters with changes in body mass during progressive acute dehydration. DESIGN: Twelve euhydrated males reported to the laboratory following an overnight fast and cycled ...
Moran Daniel S - - 2004
A new method for non-invasive measurement of the human state of hydration is presented. This method is based on frequency-dependent absorptiometry of radio-waves passing through tissues. A device utilizing this method was constructed and applied to 12 young (24 +/- 1) male volunteers, who were dehydrated for 1-2.5% of their ...
McLellan T M - - 2004
It was the purpose of this study to examine whether replacing long pants (P) with shorts (S) would reduce the heat stress of wearing firefighting protective clothing during exercise in a warm environment. Twenty-four Toronto Firefighters were allocated to one of four groups that performed heavy (H, 4.8 km x ...
Shirreffs Susan M - - 2004
For a person undertaking regular exercise, any fluid deficit that is incurred during one exercise session can potentially compromise the next exercise session if adequate fluid replacement does not occur. Fluid replacement after exercise can, therefore, frequently be thought of as hydration before the next exercise bout. The importance of ...
Abu-Zidan Fikri M - - 2004
BACKGROUND: Ultrasound is widely accepted as a valuable diagnostic tool for detecting intra-abdominal and intrathoracic bleeding in trauma patients. Nevertheless, many doctors are reluctant to use it because they do not have sufficient training. This study aimed to define intra-abdominal and intrathoracic fluid volumes that can be detected by sonography ...
MarszaƂek Anna - - 2004
The aim of the study was to compare heat strain among different age groups of men in protective clothing during short-term physical work. Eight young (20-29 years), 6 middle-aged (41-55 years), and 6 older (58-65 years) men exercised for 30 min on a cycle ergometer (40% V(O2 max)) in 2 ...
Coyle Edward F - - 2004
The amounts of water, carbohydrate and salt that athletes are advised to ingest during exercise are based upon their effectiveness in attenuating both fatigue as well as illness due to hyperthermia, dehydration or hyperhydration. When possible, fluid should be ingested at rates that most closely match sweating rate. When that ...
Proquitté Hans - - 2004
During partial liquid ventilation (PLV) the knowledge of the quantity of exhaled perfluorocarbon (PFC) allows a continuous substitution of the PFC loss to achieve a constant PFC level in the lungs. The aim of our in vitro study was to determine the PFC loss in the mixed expired gas by ...
Lancaster G I - - 2004
The present study tested the hypothesis that in response to physical stress the human brain has the capacity to release heat shock protein 72 (Hsp72) in vivo. Therefore, 6 humans (males) cycled for 180 minutes at 60% of their maximal oxygen uptake, and the cerebral Hsp72 response was determined on ...
Romer Lee M - - 2004
Exercise in the heat has detrimental effects on circulation that might negatively influence endurance performance. If blood is diverted away from the inspiratory muscles to the skin during exercise in the heat, exercise-induced inspiratory muscle fatigue might be exacerbated. Thus, we hypothesised that prolonged heavy endurance exercise in the heat ...
Thornley Leo J - - 2003
BACKGROUND: We investigated the utility of finger temperature, hand heat flux, and mean skin temperature as indices of overall thermal balance during nonuniform thermal manipulations combined with exercise, with a view to identifying useful feedback sites for input into personal thermal control systems. METHODS: There were 16 subjects who performed ...
Patterson Mark J - - 2004
We tested the hypothesis that local sweat rates would not display a systematic postadaptation redistribution toward the limbs after humid heat acclimation. Eleven nonadapted males were acclimated over 3 wk (16 exposures), cycling 90 min/day, 6 days/wk (40 degrees C, 60% relative humidity), using the controlled-hyperthermia acclimation technique, in which ...
Shibasaki Manabu - - 2003
Isometric handgrip exercise (IHG) increases sweating rate without changing core or skin temperatures. The contribution of central command resulting in increases in sweating rate during IHG is unknown. To investigate this question, seven subjects performed IHG (35 % maximum voluntary contraction (MVC) for 2 min) followed by 2-min of post-exercise ...
Heymsfield S B - - 2003
Early investigators recognized a link between a mammal's rate of heat production and its body size and composition. A particular challenge has been to establish whether between- and within-species differences exist in the rate of cellular energy exchange, notably as resting metabolic rate. Between-species or between-individual differences in body size ...
LeBlanc J - - 2003
Tolerance to cold and heat exposure shows large variations for which there is still insufficient explanation. On the other hand the relationship between the responses to mental stress and individual personality is well documented. The aim of this study was then to find if personality traits have some influence on ...
Wagner A J - - 2003
We investigate by lattice Boltzmann methods the effect of inertia on the deformation and breakdown of stability of a two-dimensional fluid droplet surrounded by fluid of equal viscosity (in a confined geometry) whose shear rate is increased very slowly. We give evidence that in two dimensions inertia is necessary for ...
Roberts Stephen P - - 2003
In Drosophila, heat shock (HS) during the pupal stage chronically hinders adult locomotor performance by disrupting wing development and cellular and/or tissue-level mechanisms that support walking and flight. Furthermore, heat pretreatment (PT) protects locomotor function against these disruptions. HS flies with abnormal wings were less able to alter trajectory in ...
Niess A M - - 2003
AIM: Tolerance to exercise in heat exhibits great interindividual variability. We questioned whether individual differences in self-reported heat tolerance within a group of endurance trained athletes are linked to the cardiocirculatory, thermoregulatory and hormonal response to endurance exercise in heat. METHODS: Using a rating scale to assess the individual degree ...
Noakes Tim - - 2003
During endurance exercise, about 75% of the energy produced from metabolism is in the form of heat, which cannot accumulate. The remaining 25% of energy available can be used for movement. As running pace increases, the rate of heat production increases. Also, the larger one's body mass, the greater the ...
Marino Frank E - - 2004
The purpose of this study was to examine the running performances and associated thermoregulatory responses of African and Caucasian runners in cool and warm conditions. On two separate occasions, 12 (n = 6 African, n = 6 Caucasian) well-trained men ran on a motorized treadmill at 70% of peak treadmill ...
Prat Gwénaël - - 2003
OBJECTIVE: To evaluate the effects of the humidification device on respiratory, hemodynamic and gas exchange parameters in acute respiratory distress syndrome (ARDS) patients. DESIGN: A prospective open study. SETTING: A medical intensive care unit of a university hospital. PATIENTS: Acute respiratory distress syndrome patients, with hypercapnia (PaCO(2)>60 mmHg). INTERVENTION: A ...
Cheuvront Samuel N - - 2003
Dehydration alters cardiovascular, thermoregulatory, central nervous system, and metabolic functions. One or more of these alterations will degrade endurance exercise performance when dehydration exceeds 2% of body weight. These performance decrements are accentuated by heat stress. To minimize the adverse consequences of body water deficits on endurance exercise performance, it ...
Cadarette Bruce S - - 2003
This study compared endurance in a U.S. Army developmental Occupational Safety and Health Administration Level B personal protective equipment (PPE) system against the toxicological agent protective (TAP) suit, the Army's former standard PPE for Level A and Level B toxic environments. The developmental system consisted of two variations: the improved ...
Yamazaki Fumio - - 2003
In the present study, to test the hypothesis that exercise-heat acclimation increases orthostatic tolerance via the improvement of cardiac baroreflex control in heated humans, we examined cardiac baroreflex and thermoregulatory responses, including cutaneous vasomotor and sudomotor responses, during whole body heating before and after a 6-day exercise-heat acclimation program [4 ...
Demirel Haydar A - - 2003
Overexpression of heat shock protein (HSP)72 is associated with cardioprotection. Hyperthermia-induced HSP72 overexpression is attenuated with senescence. While exercise also increases myocardial HSP72 in young animals, it is unknown whether this effect is attenuated with aging. Therefore, we investigated the effect of aging on exercise-induced myocardial heat shock factor (HSF)-1 ...
Wald N - - 2003
Sodium supplementation during or after exertion improves hydration. We hypothesized that it may therefore improve well being after exercise-induced sodium loss. To avoid cognitive-biased interpretations of the taste of salt, we used untasted salt in swallowed capsules to condition preference for the flavor of a drink. In four 90 min ...
Rianon N - - 2003
The purpose of this study was to determine whether a simple noninvasive sweat collection method using skin patches would be useful in monitoring sweat Ca and to determine changes in dermal Ca loss during a bed rest study testing a resistive exercise countermeasure. The study showed that the technique was ...
Oh Robert Chu Hwan - - 2003
This is a case report of a highly trained, heat-acclimatized infantry soldier who suffered from exertional heatstroke during a 12-mile road march shortly after taking an ephedra-based supplement. Heatstroke is associated with systemic complications and a high mortality rate if not recognized early. Control of risk factors is key to ...
Donaldson G C - - 2003
This paper reviews the basic thermoregulatory physiology of healthy people in relation to hazards from external heat stress and internal heat loads generated by physical exercise or radiofrequency (RF) radiation. In addition, members of the population are identified who may be particularly vulnerable to the effects of heat stress. These ...
Marino Frank E - - 2003
It is equivocal whether glycerol hyperhydration improves exercise performance and thermoregulation in the heat. The purpose of this study was to compare the effectiveness of glycerol with water hyperhydration, using a reliable, self-paced variable-intensity cycling protocol under hot, humid conditions. Seven moderately-to-well trained subjects ingested either a solution consisting of ...
Smalley Brian - - 2003
OBJECTIVE: Exertional heat illnesses (heat stroke, heat exhaustion, and heat cramps) are a serious problem in military operations. Air Force basic military training at Lackland Air Force Base is a prime example of where exertional heat illnesses can occur. This project was conducted to evaluate the problem o exertional heat ...
Dirks Jesper - - 2003
The heat/capsaicin sensitization model induces cutaneous sensitization by using a combination of heat and topical capsaicin. It has been suggested that the stability and duration of the cutaneous sensitization are due to a synergistic effect between heat and capsaicin. The aim of this study was to evaluate a possible synergistic ...
Ormerod Jennifer K - - 2003
The purposes of this study were to characterize measures of fluid intake and perception of thirst in women over a 6-week period of exercise-heat acclimation and outdoor training and examine if this lengthy acclimation period would result in changes in fluid intake that differ from those previously reported in men ...
Gaussier Hélène - - 2003
Fourier transform infrared (FTIR) spectroscopy was used to investigate the secondary structure of pediocin PA-1 in different aqueous media in relation to its antimicrobial activity. The experiments were performed at pD (pH meter corrected for deuterium isotope effect) 6, 7, and 8 and during a heating-cooling cycle of 20-80 degrees ...
Crandall C G - - 2003
Cutaneous vasodilation and sweat rate are reduced during a thermal challenge after simulated and actual microgravity exposure. The effects of microgravity exposure on cutaneous vasodilator capacity and on sweat gland function are unknown. The purpose of this study was to test the hypothesis that simulated microgravity exposure, using the 6 ...
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