Search Results
Results 351 - 400 of 1103
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Kuwahara Tomoko - - 2005
We evaluated the effects of the menstrual cycle and physical training on heat loss (sweating and cutaneous vasodilation) responses during moderate exercise in a temperate environment. Ten untrained (group U) and seven endurance-trained (group T) women (maximal O2 uptake of 36.7+/-1.1 vs. 49.4+/-1.7 ml.kg-1.min-1, respectively; P<0.05) performed a cycling exercise ...
Webborn N - - 2005
Athletes with spinal cord injury (SCI), and in particular tetraplegia, have an increased risk of heat strain and consequently heat illness relative to able-bodied individuals. Strategies that reduce the heat strain during exercise in a hot environment may reduce the risk of heat illness. To test the hypotheses that precooling ...
McCord Gregg R - - 2005
The dramatic increase in skin blood flow and sweating observed during heat stress is mediated by poorly understood sympathetic cholinergic mechanisms. One theory suggests that a single sympathetic cholinergic nerve mediates cutaneous active vasodilation (AVD) and sweating via cotransmission of separate neurotransmitters, because AVD and sweating track temporally and directionally ...
Davis Scott L - - 2005
This investigation tested the hypothesis that cholinergic sweat function of individuals with multiple sclerosis (MS) (MS-Con; n = 10) is diminished relative to matched healthy control subjects (Con; n = 10). In addition, cholinergic sweat function was determined before and after 15 wk of aerobic training in a subgroup of ...
Maughan R J - - 2005
There are few data in the published literature on sweat loss and drinking behaviour in athletes training in a cool environment. Sweat loss and fluid intake were measured in 17 first-team members of an elite soccer team training for 90 min in a cool (5 degrees C, 81% relative humidity) ...
Houghton Belinda L - - 2005
PURPOSE: Oral contraceptives influence the regulation of cutaneous vascular tone, and both estrogen and progesterone have been shown to affect nitric oxide (NO)-mediated vasodilation. We tested the hypothesis that cutaneous vascular conductance (CVC) during passive heating would be lower in women taking oral contraceptives with higher progestational bioactivity compared with ...
Armstrong Lawrence E - - 2005
Although endogenous and exogenous steroid hormones affect numerous physiological processes, the interactions of reproductive hormones, chronic exercise training, and heat acclimation are unknown. This investigation evaluated the responses and adaptations of 36 inactive females [age 21 +/- 3 (SD) yr] as they undertook a 7- to 8-wk program [heat acclimation ...
Appleton K M - - 2005
It has previously been suggested that the perceived pleasantness of a food item in any situation may be directly related to the physiological usefulness of that item to the consumer in that situation. This study investigated changes in the perceived pleasantness of fluids before and after fluid loss through exercise-an ...
Elez-Martínez Pedro - - 2004
Saccharomyces cerevisiae is often associated with the spoilage of fruit juices. The purpose of this study was to evaluate the effect of high-intensity pulsed electric field (HIPEF) treatment on the survival of S. cerevisiae suspended in orange juice. Commercial heat-sterilized orange juice was inoculated with S. cerevisiae (CECT 1319) (10(8) ...
Lambert G Patrick - - 2004
Reduced splanchnic blood flow and hyperthermia during exercise-heat stress can produce gastrointestinal barrier dysfunction and increased gastrointestinal permeability. This may allow endotoxin to enter the internal environment, causing local and systemic immune responses. These responses may be involved in the cause and outcome of exertional heatstroke. Countermeasures may reduce gastrointestinal ...
Maltais Désirée - - 2004
PURPOSE: When metabolic rate during arm-cranking in the heat is equated between children and adolescents with cerebral palsy (CP) and matched controls (CON), there are no relevant intergroup differences in heat strain. The metabolic rate, however, is known to be higher in CP during treadmill walking. The purpose of this ...
Cheuvront Samuel N - - 2004
The purpose of this study was to quantify the variability and stability of 1st morning body mass (BM) fluctuations during daily exercise in the heat while following traditional fluid intake guidance. Data from 65 men were examined retrospectively. BM fluctuations were monitored over 4 to 15 consecutive days. Group daily ...
Maughan Ron - - 2004
Exercise in the heat poses a formidable challenge to the body's ability to control its internal environment due to the high rates of metabolic heat production and heat gain by physical transfer from the environment. In an attempt to restrict the rise in core temperature, an increased rate of sweat ...
Cheuvront Samuel N - - 2004
The serotonin system may contribute to reduced human performance when hypohydrated in the heat. This study determined whether branched-chain amino acid (BCAA) supplementation could sustain exercise and cognitive performance in the heat (40 degrees C dry bulb, 20% relative humidity) when hypohydrated by 4% of body mass. Seven heat-acclimated men ...
Morgan R M - - 2004
AIM: To determine whether acute exercise-heat-induced dehydration affects sweat composition, eight males cycled for 2 h at 39.5 +/- 1.6% VO2peak on two separate occasions in a hot-humid environment (38.0 +/- 0.0 degrees C, 60.0 +/- 0.1% relative humidity). METHODS: During exercise, subjects ingested either no fluid (dehydration) or a ...
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 ...
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