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Results 401 - 450 of 1087
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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)) ...
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 ...
Launay Jean-Claude - - 2002
OBJECTIVE: A survival sojourn in a tropical climate exposes subjects to 2 main constraints: food restriction and tropical climatic conditions. We hypothesized that such a sojourn could modify anthropological characteristics and thermoregulatory responses to heat and cold on return. METHODS: Eight European male subjects were submitted to a sweating test ...
Abrams L S - - 2001
The objectives of this randomized, open-label, three-period, incomplete block design study were to evaluate the pharmacokinetics of norelgestromin (NGMN) and ethinyl estradiol (EE) delivered by the contraceptive patch, Ortho Evra/Evra, and to evaluate patch adhesion under conditions of heat, humidity, and exercise. During each treatment period, 30 healthy women wore ...
Cian C - - 2001
This study investigated the effects of heat exposure, exercise-induced dehydration and fluid ingestion on cognitive performance. Seven healthy men, unacclimatized to heat, were kept euhydrated or were dehydrated by controlled passive exposure to heat (H, two sessions) or by treadmill exercise (E, two sessions) up to a weight loss of ...
Nadler S F - - 2001
OBJECTIVE: To investigate the influence of superficial heat on the fatigue cascade of the upper trapezius muscle in subjects with myofascial pain and matched normal controls. DESIGN: In a prospective randomized block crossover pilot study, eight female subjects, ages 20-35 yr, with upper trapezius muscle trigger points and eight matched ...
Krustrup P - - 2001
1. The aim of the present study was to examine muscle heat production, oxygen uptake and anaerobic energy turnover throughout repeated intense exercise to test the hypotheses that (i) energy turnover is reduced when intense exercise is repeated and (ii) anaerobic energy production is diminished throughout repeated intense exercise. 2. ...
Saunders P U - - 2001
To investigate the influence of heat stress on the regulation of skeletal muscle carbohydrate metabolism, six active, but not specifically trained, men performed 5 min of cycling at a power output eliciting 70% maximal O2 uptake in either 20 degrees C (Con) or 40 degrees C (Heat) after 20 min ...
Arcas J - - 2001
Topiramate (TPM) is an antiepileptic agent, first licensed in the United Kingdom in 1994, that is used in the treatment of patients with refractory seizure disorders. TPM is a monosaccharide d-fructose derivate, with sulfamate function, and so far, few adverse side effects have been reported. We describe three patients with ...
Mitlöhner F M - - 2001
One hundred twelve crossbred feedlot heifers were used in two experiments to assess the impact of heat stress and its relief by shade and(or) water misting on behavior, physiology, performance, and carcass traits. Treatments were 1) no shading or misting (CONT); 2) only misting (MIST); 3) only shading (SHADE); and ...
Grünenfelder J - - 2001
OBJECTIVE: Studies showed that the expression of heat shock protein 70 (HSP70) by whole-body hyperthermia or warming of the heart is associated with protection against ischemia/reperfusion injury. The aim of this study is to determine a time-related response of HSP70 expression through topical cardiac warming with correlation to cytokine production. ...
Hsieh C - - 2001
Although thermoregulatory sweat testing is commonly used to assess the autonomic nervous system, the power of this stimulus to induce sweating has not been studied. In 8 healthy male subjects, the authors quantitated sweat rates, core temperature, heart rate, and blood pressure during clinical thermoregulatory sweat testing, a separate exercise ...
Shibasaki M - - 2001
1. Isometric handgrip (IHG) exercise increases sweat rate and arterial blood pressure, and both remain elevated during post-exercise ischaemia. The purpose of this study was to identify whether the elevation in arterial blood pressure during post-exercise ischaemia contributes to the increase in sweating. 2. In normothermia and during whole-body heating, ...
Montain S J - - 2001
Exercise-related hyponatremia is an infrequent but potentially life-threatening accompaniment of prolonged exercise. This condition results from sodium losses in sweat, excessive water intake, or both. We review the risk factors for development of this condition and discuss evidence that there is a population at increased risk of hyponatremia during prolonged ...
Volek J S - - 2001
PURPOSE: This investigation was designed to examine the influence of creatine (Cr) supplementation on acute cardiovascular, renal, temperature, and fluid-regulatory hormonal responses to exercise for 35 min in the heat. METHODS: Twenty healthy men were matched and then randomly assigned to consume 0.3 g.kg(-1) Cr monohydrate (N = 10) or ...
Devlin L H - - 2001
The effects of exercise-induced hypohydration on the motor skill performance of cricket bowling was examined in seven medium-fast bowlers who performed a random order of two experimental trials. Trials consisted of a bowling test (36 deliveries; PREBOWL) in a thermoneutral (16+/-2 degrees C) environment followed by approximately 1 hr of ...
Forsthoff A - - 2001
For International Standard ISO 7933 (Hot environments-analytical determination and interpretation of thermal stress using calculation of required sweat rate. International Organization for Standardization, Geneva, 1989) it has been questioned whether the heat stress index "required sweat rate" is applicable in environments where mean radiant temperature (t(r)) exceeds dry air temperature ...
Maresh C M - - 2001
PURPOSE: The purpose of the study was to compare the effects of a brief period (20 min) of intravenous (IV) fluid rehydration and oral (ORAL) rehydration on ratings of perceived exertion (RPE), thirst, and thermal sensation (TS) during exercise in the heat. METHODS: After dehydration (-4% of body weight), eight ...
Smith C D - - 2001
A 40-year-old man awoke with exuberant sustained sweating of the entire left side of the body, which became intermittent over the next few days. MRI indicated a single linear hyperintensity in the right posterior hypothalamus, diminishing on a repeat scan. He continues to have episodes of left unilateral sweating precipitated ...
Kondo N - - 2001
The purpose of this study was to identify the pattern of change in the density of activated sweat glands (ASG) and sweat output per gland (SGO) during dynamic constant-workload exercise and passive heat stress. Eight male subjects (22.8 +/- 0.9 yr) exercised at a constant workload (117.5 +/- 4.8 W) ...
Levitus S - - 2001
We compared the temporal variability of the heat content of the world ocean, of the global atmosphere, and of components of Earth's cryosphere during the latter half of the 20th century. Each component has increased its heat content (the atmosphere and the ocean) or exhibited melting (the cryosphere). The estimated ...
Leiper J B - - 2001
Total body water (TBW) and water turnover rates (WTR) of six competitive male cyclists (CG) and six age-matched sedentary men (SG) were determined using deuterium oxide dilution and elimination. During the 7 day study, individuals in the CG cycled daily outside on average 50 (range 12-146) km at an average ...
Levine L - - 2001
BACKGROUND: The purpose of this study was to compare thermoregulatory and subjective responses of 12 test subjects (10 male, 2 female) wearing 5 different Joint Service Lightweight Integrated Suit Technology (JSLIST) prototype and 3 different currently fielded control chemical/ biological (CB) protective overgarments. METHODS: The overgarments were compared while subjects ...
Young A J - - 2001
Cold exposure facilitates body heat loss which can reduce body temperature, unless mitigated by enhanced heat conservation or increased heat production. When behavioral strategies inadequately defend body temperature, vasomotor and thermogenic responses are elicited, both of which are modulated if not mediated by sympathetic nervous activation. Both exercise and shivering ...
Wu T - - 2001
Antibodies against heat shock or stress proteins (Hsps) have been reported in a number of diseases in which they may be involved in the pathogenesis of the disease or may be of use for prognosis. Heat-induced diseases, such as heat cramps, heat exhaustion, or heat stroke, are frequent in hot ...
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