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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 ...
González-Alonso José - - 2003
BACKGROUND: A classic, unresolved physiological question is whether central cardiorespiratory and/or local skeletal muscle circulatory factors limit maximal aerobic capacity (VO2max) in humans. Severe heat stress drastically reduces VO2max, but the mechanisms have never been studied. METHODS AND RESULTS: To determine the main contributing factor that limits VO2max with and ...
Gavin Timothy P - - 2003
Exercise increases heat production. During exercise in both warm and cold conditions, the major dilemma is the dissipation of the heat produced from muscular activity. The use of clothing generally represents a layer of insulation and as such imposes a barrier to heat transfer and evaporation from the skin surface. ...
Nielsen Bodil - - 2003
This review focuses on cerebral changes during combined exercise and heat stress, and their relation to fatigue. Dynamic exercise can elevate the core temperature rapidly and high internal body temperatures seem to be an independent cause of fatigue during exercise in hot environments. Thus, in laboratory settings, trained participants become ...
Vangelova K - - 2002
The aim of the investigation was to study the effect of long term repeated heat exposure on the excretion rates of stress hormones of workers in glass manufacturing unit. Sixteen operators, exposed to heat, were studied during the hot period and compared to a control group of 16 subjects, working ...
Nybo Lars - - 2002
Brain temperature appears to be an important factor affecting motor activity, but it is not known to what extent brain temperature increases during prolonged exercise in humans. Cerebral heat exchange was therefore evaluated in seven males during exercise with and without hyperthermia. Middle cerebral artery mean blood velocity (MCA V(mean)) ...
Aoyagi Teruhiko T Department of Cardiovascular Medicine, Japanese Red Cross Medical Center , Tokyo, Japan - - 2002
Various substances have been introduced in relation with cardiac hypertrophy almost always with controversy in their roles in signal transduction. Those controversies may attribute to the diversity of cardiac hypertrophy. We previously showed that calcineurin was activated in physiological left ventricular hypertrophy (LVH) induced by voluntary exercise training, but not ...
Murakami Masamoto - - 2002
The eccrine gland is one of the major cutaneous appendages and secretes sweat. Its principal function is thermoregulation during exposure to a hot environment or physical exercise. In addition to this function, we show that LL-37, a member of cathelicidin family of anti-microbial peptides, is expressed in sweat. LL-37 protein ...
Bassett David R DR - - 2002
Beginning in 1910, A. V. Hill performed careful experiments on the time course of heat production in isolated frog muscle. His research paralleled that of the German biochemist Otto Meyerhof, who measured the changes in muscle glycogen and lactate during contractions and recovery. For their work in discovering the distinction ...
Minson Christopher T - - 2002
Cutaneous vasodilation is reduced in healthy older vs. young subjects; however, the mechanisms that underlie these age-related changes are unclear. Our goal in the present study was to determine the role of nitric oxide (NO) and the axon reflexes in the skin blood flow (SkBF) response to local heating with ...
DuBose, D. A.
Exposure of U.S. Army personnel to strenuous physical stress under harsh environments is often a necessary circumstance to accomplish a military mission. Such exposure can significantly contribute to the casualty rate. To reduce casualties, physiological markers are required to characterize training programs relative to their capacity to impart resistance to ...
Jimenez Chantal - - 2002
PURPOSE: The present study was assessed to study the restoration of the vascular compartment by rehydration after heat exposure or exercise. METHODS: Eight subjects completed four trials in a randomized order: 2.7% dehydration of body mass by passive controlled hyperthermia once with rehydration and once without rehydration during recovery, and ...
Tikuisis Peter - - 2002
PURPOSE: The physiological strain index (PSI) has been proposed as a universally applicable measure of exercise-heat strain. Unknown is whether this index, based on normalized increases in core temperature and heart rate, is matched by its perceptual analog. METHODS: By using a similar mathematical construct to the PSI, the perceptions ...
Johnson Arthur T - - 2002
Oxygen consumption, heat production, and muscular efficiency for walking are parameters important to know for ergonomics models and equipment design. Most of these assume that the oxygen consumption and heat production of downhill walking are the same as for uphill walking. Eight subjects wearing insulating clothing walked on a treadmill ...
Morgan Amy L - - 2002
BACKGROUND: The purpose was to study the effects of age on body fluid distribution during exercise and exercise combined with heat stress. METHODS: Ten young (Y; 23.2 +/-0.7 yr) and eight older (O; 65.3 +/- 1.0 yr) men performed two 80-min intermittent exercise bouts on a cycle ergometer at 50% ...
Matsumoto Yasuhiro - - 2002
The process of heat loss has been shown to be a key pathway regulating sleepiness in humans. The influence of physical exercise with its attending heat production on subjective sleepiness and performance levels during total sleep deprivation (SD) was assessed in eight healthy young volunteers (mean age 21.1 years). Each ...
Dejmek Petr - - 2002
The impedance at frequencies of 1-1000 kHz and dynamic bending storage modulus measured by the vibrating reed method were compared for potato tuber tissue, which had been processed by various methods. Raw potato tuber tissue strips were either heated for 30 min up to 100 degrees C or frozen-thawed. Some ...
Shastry S - - 2002
In this study, we examined expression of heat shock proteins (HSP) 70 and 90 in human leucocytes after moderate-to-heavy exercise. We also compared baseline levels of HSP70 and HSP90 in trained (TR) and untrained (UT) subjects. Eleven TR subjects ran on a treadmill for 1 h at 70% of maximal ...
Deptula Joseph - - 2002
Modified ultrafiltration (MUF) has been described and utilized for the removal of extracellular water in the immediate postcardiopulmonary bypass (CPB) period. This technique has been associated with improved hematological status and hemodynamic stability post cardiopulmonary bypass. Hypothermia during the MUF period has been described as a complication associated with this ...
Fleming Sherry D - - 2002
Prior induction of heat shock protein 70 (HSP70) protects against ischemia-reperfusion (I/R) mucosal injury, but the ability of HSP70 to affect I/R-induced alterations in epithelial cell function is unknown. Rats subjected to whole body hyperthermia (41.5-42 degrees C for 6 min) increased HSP70 and heat shock factor 1 mRNA expression, ...
Kondo Narihiko - - 2002
Changes in the number of activated sweat glands (ASGs) and sweat output per gland (SGO) with increased exercise intensity during sustained static exercise were investigated. Fourteen male subjects performed 20, 35, and 50% maximal voluntary contraction (MVC) for 60 s with the right hand (exercised arm) at an ambient temperature ...
Cypser James R - - 2002
We demonstrate here that the nematode Caenorhabditis elegans displays broad hormetic abilities. Hormesis is the induction of beneficial effects by exposure to low doses of otherwise harmful chemical or physical agents. Heat as well as pretreatment with hyperbaric oxygen or juglone (a chemical that generates reactive oxygen species) significantly increased ...
Eikesdal H P - - 2002
We investigated the anti-vascular activity of local hyperthermia (44 degrees C, 60 min) in s.c. BT4An rat gliomas, and the influence on tumour growth of hyperthermia and the anti-angiogenic compound batimastat (30 mg/kg i.p.). Heat-induced vascular damage was assessed in small (82 mm3) and large (171 mm3) tumours using confocal ...
Tisljar M - - 2002
1. The aim of this study was to investigate pathomorphological changes in broiler chicks fed with different doses of gizzerosine, a substance produced during the heat treatments of fish meal. 2. The experiment was carried out in Ross broiler chicks which were divided into three groups: group A received 100% ...
Brake Derrick J - - 2002
The development of a rational heat stress index called thermal work limit (TWL) is presented. TWL is defined as the limiting (or maximum) sustainable metabolic rate that euhydrated, acclimatized individuals can maintain in a specific thermal environment, within a safe deep body core temperature (< 38.20 degrees C) and sweat ...
Barry Leon - - 2002
The atmospheric heat transport on Earth from the Equator to the poles is largely carried out by the mid-latitude storms. However, there is no satisfactory theory to describe this fundamental feature of the Earth's climate. Previous studies have characterized the poleward heat transport as a diffusion by eddies of specified ...
Zacur Howard A - - 2002
OBJECTIVE: To assess the adhesive reliability of the contraceptive patch (Ortho Evra/Evra). DESIGN: Pooled data of 3,319 women from three contraceptive studies of up to 13 treatment cycles; a subset of 325 women of the pooled data from warm and humid climates; and 30 women from a three-period, crossover exercise ...
Armstrong Lawrence E - - 2002
The role of the central nervous system (CNS) in the control of human heat acclimation (HA) and HA adaptations at the ultrastructural and biochemical level are not well described, although empirical evidence demonstrates that the hypothalamus adjusts thermoregulation subsequent to 8-14 days of exercise in a hot environment. Therefore, numerous ...
Patterson M J - - 2002
To determine whether induced metabolic alkalosis affects sweat composition, 10 males cycled for 90 min at 62.5 +/- 1.3% peak oxygen uptake, on two separate occasions. Subjects ingested either empty capsules (placebo) or capsules containing NaHCO3- (0.3 g kg-1 body mass; six equal doses) over a 2-h period, which commenced ...
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