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Keating Charlotte C Monash Alfred Psychiatry Research Centre (MAPrc), The Alfred Hospital, 1st floor, Old Baker Building, Commercial Road, Prahran, VIC, 3181, Australia. - - 2011
In anorexia nervosa (AN), reward contamination likely plays a significant role in maintenance of the illness. Reward contamination is a context in which patients' behaviors of self-starvation and excessive exercise, while initially rewarding, become aversive, even punishing; but patients may not recognize the punishing and conflicted/contaminated behaviors. An emerging neurocircuit ...
Vanos Jennifer K - - 2010
Human thermal comfort assessments pertaining to exercise while in outdoor environments can improve urban and recreational planning. The current study applied a simple four-segment skin temperature approach to the COMFA (COMfort FormulA) outdoor energy balance model. Comparative results of measured mean skin temperature ([Formula: see text]) with predicted [Formula: see ...
Miyagawa Ken - - 2011
We examined whether less convective heat loss during exercise at high altitude than at sea level was partially caused by reduced cutaneous vasodilation due to enhanced plasma water loss into contracting muscles and whether it was caused by hypoxia rather than by hypobaria. Seven young men performed cycling exercise for ...
Elliott Jonathan E - - 2011
Concern has been raised that altering the fraction of inspired O₂ (Fi(O₂)) could accelerate or decelerate microbubble dissolution time within the pulmonary vasculature and thereby invalidate the ability of saline contrast echocardiography to detect intrapulmonary arteriovenous shunt in subjects breathing either a low or a high Fi(O₂). The present study ...
Ogawa Takeshi - - 2010
To test the hypothesis that maximal exercise pulmonary ventilation (VE max) is a limiting factor affecting maximal oxygen uptake (VO2 max) in moderate hypobaric hypoxia (H), we examined the effect of breathing a helium-oxygen gas mixture (He-O(2); 20.9% O(2)), which would reduce air density and would be expected to increase ...
Katayama Keisho - - 2010
PURPOSE: It is reported that the rate of locomotor muscle fatigue development during intermittent isometric exercise in hypoxia is accelerated compared with normoxia. In contrast, when sustained isometric contractions are used, some studies do not show any effect of hypoxia on fatigue development. Increased intramuscular pressure during sustained isometric exercise ...
Burtscher M - - 2010
We investigated the effects of two 5-wk periods of intermittent hypoxia on running economy (RE). 11 male and female middle-distance runners were randomly assigned to the intermittent hypoxia group (IHG) or to the control group (CG). All athletes trained for a 13-wk period starting at pre-season until the competition season. ...
Lodin-Sundström Angelica - - 2010
Spleen contraction occurs in humans during exercise, apnea, and simulated altitude, resulting in ejection of stored red blood cells into circulation. The mechanisms responsible for initiating the contraction are not fully known: hypoxia is likely involved, but other, unknown factors may also contribute. To reveal the initiating factors, we studied ...
Mollard Pascal - - 2010
The purpose of this study was to compare arterial and arterialized blood gases during normoxic and hypoxic exercise. In the same conditions, earlobe pulse oximetry O(2) saturation (Sp(O2)) was compared to arterial oxygen saturation (Sa(O2)). Ten men performed incremental cycle ergometer tests, in normoxia and hypoxia (FI(O2) = 0.127). Blood ...
Fukuda Taira - - 2010
It has been unclear how acute hypoxia at moderate altitude affects stroke volume (SV), an index of cardiac function, during exercise. The present study was conducted to reveal whether acute normobaric hypoxia might alter SV during exercise.Nine healthy male subjects performed maximal exercise testing under normobaric normoxic, and normobaric hypoxic ...
Wang Jong-Shyan - - 2010
Hypoxic preconditioning prevents cerebrovascular/cardiovascular disorders by increasing resistance to acute ischemic stress, but severe hypoxic exposure disturbs vascular hemodynamics. This study compared how various exercise regimens with/without hypoxia affect hemodynamics and oxygenation in cardiac, muscle, and cerebral tissues during severe hypoxic exposure. Sixty sedentary males were randomly divided into five ...
Heinonen Ilkka H - - 2010
Although many effects of both acute and chronic hypoxia on the circulation are well characterized, the distribution and regulation of blood flow (BF) heterogeneity in skeletal muscle during systemic hypoxia is not well understood in humans. We measured muscle BF within the thigh muscles of nine healthy young men using ...
Nordsborg Nikolai B - - 2010
It was investigated whether skeletal muscle K(+) release is linked to the degree of anaerobic energy production. Six subjects performed an incremental bicycle exercise test in normoxic and hypoxic conditions prior to and after 2 and 8 wk of acclimatization to 4,100 m. The highest workload completed by all subjects ...
Naeije R - - 2010
Altitude exposure is associated with decreased exercise capacity and increased pulmonary vascular resistance (PVR). Echocardiographic measurements of pulmonary haemodynamics and a cardiopulmonary exercise test were performed in 13 healthy subjects at sea level, in normoxia and during acute hypoxic breathing (1 h, 12% oxygen in nitrogen), and in 22 healthy ...
Debevec Tadej - - 2010
Although training in hypoxia has been suggested to improve sea level and altitude performance, most studies have only evaluated its effect on maximal aerobic capacity in either normoxia or hypoxia. The present study evaluated the effect of a live low-train high training regimen on both normoxic and hypoxic endurance performance ...
Slessarev Marat - - 2010
We used Duffin's isoxic hyperoxic ( mmHg) and hypoxic ( mmHg) rebreathing tests to compare the control of breathing in eight (7 male) Andean highlanders and six (4 male) acclimatizing Caucasian lowlanders after 10 days at 3850 m. Compared to lowlanders, highlanders had an increased non-chemoreflex drive to breathe, characterized ...
Farahani Ali Vasheghani - - 2010
Sudden death of a competitive athlete is a tragedy that is usually caused by a previously unsuspected cardiovascular disease. The aim of this study was to clarify the role of noninvasive testing in pre-participation cardiovascular evaluation of elderly wrestlers. We included 63 Iranian elderly wrestlers who participated in Tehran international ...
Schmutz Silvia - - 2010
Metabolic stress is believed to constitute an important signal for training-induced adjustments of gene expression and oxidative capacity in skeletal muscle. We hypothesized that the effects of endurance training on expression of muscle-relevant transcripts and ultrastructure would be specifically modified by a hypoxia complement during exercise due to enhanced glycolytic ...
Ando Soichi - - 2010
The purpose of this study was to test the hypothesis that decrease in cerebral oxygenation compromises an individual's ability to respond to peripheral visual stimuli during exercise. We measured the simple reaction time (RT) to peripheral visual stimuli at rest and during and after cycling at three different workloads [40%, ...
Esposito Fabio - - 2010
To assess the effects of respiratory muscle training (RMT) on maximum oxygen uptake (VO2max) in normoxia and hypoxia, 9 healthy males (age 24 +/- 4 years; stature 1.75 +/- 0.08 m; body mass 72 +/- 9 kg; mean +/- SD) performed on different days maximal incremental tests on a cycle ...
Morris Chloe - - 2010
Physical activity interventions have been demonstrated to improve health-related quality of life and to be of special benefit to older adults with specific chronic conditions including arthritis, hypertension, diabetes mellitus, and heart disease. This study examined the extent and social determinants of physical exercise in elderly men in Jamaica. ...
Osawa Takuya - - 2010
The purpose of this study was to investigate the effects of acute hypoxia on the inflection point of muscle oxygenation (IPMO) using near-infrared spectroscopy during incremental bicycle exercise. Eight male subjects (age: 22 +/- 2 years) performed two ramp incremental bicycle exercise tests until exhaustion under each normoxic and hypoxic ...
Jourdan-Pineau H?l?ne - - 2010
We investigated the ability of European sea bass (Dicentrarchus labrax) to respond simultaneously to the metabolic demands of specific dynamic action (SDA) and aerobic exercise and how this was influenced by moderate hypoxia (50% air saturation). At 3 h after feeding in normoxia at 20 degrees C, SDA raised the ...
Verges Samuel - - 2010
Greater diaphragm fatigue has been reported after hypoxic versus normoxic exercise, but whether this is due to increased ventilation and therefore work of breathing or reduced blood oxygenation per se remains unclear. Hence, we assessed the effect of different blood oxygenation level on isolated hyperpnoea-induced inspiratory and expiratory muscle fatigue. ...
Ponsot Elodie - - 2010
This study investigates the role of central vs. peripheral factors in the limitation of maximal oxygen uptake (Vo(2max)) with moderate hypoxia [inspired fraction (Fi(O(2))) =14.5%]. Fifteen endurance-trained athletes performed maximal cycle incremental tests to assess Vo(2max), maximal cardiac output (Q(max)), and maximal arteriovenous oxygen (a-vO(2)) difference in normoxia and hypoxia. ...
Lecoultre Virgile - - 2010
The aim of this study was to investigate the synergistic effects of endurance training and hypoxia on endurance performance in normoxic and hypoxic conditions (approximately 3000 m above sea level) as well as on lactate and glucose metabolism during prolonged exercise. For this purpose, 14 well-trained cyclists performed 12 training ...
Klok C J - - 2009
Greater oxygen availability has been hypothesized to be important in allowing the evolution of larger invertebrates during the Earth's history, and across aquatic environments. We tested for evolutionary and developmental responses of adult body size of Drosophila melanogaster to hypoxia and hyperoxia. Individually reared flies were smaller in hypoxia, but ...
Bai C - - 2010
Hypoxia and exertion are considered as the two main factors in the development of high-altitude pulmonary oedema (HAPE), however its pathophysiology remains unclear. Therefore, we established a model in which 32 Sprague-Dawley rats were randomly assigned to normoxic rest, hypoxic rest, normoxic exercise and hypoxic exercise. An altitude of 4,700 ...
Ogoh Shigehiko - - 2009
The response of cerebral vasculature to exercise is different from other peripheral vasculature; it has a small vascular bed and is strongly regulated by cerebral autoregulation and the partial pressure of arterial carbon dioxide (Pa(CO(2))). In contrast to other organs, the traditional thinking is that total cerebral blood flow (CBF) ...
Peltonen Juha E - - 2009
To examine if cerebral (frontal cortex) and skeletal muscle (m. vastus lateralis) deoxygenation and cerebral blood flow velocity (V(mean)) in the middle cerebral artery differentiated between normoxic and hypoxic (end-tidal P(O)(2) 71 mmHg) conditions, and if they were associated with hypoxic ventilatory chemosensitivity and cerebrovascular responsiveness, 8 men performed incremental ...
Janssen C - - 2010
1. The contribution of peripheral chemoreceptors to the regulation of ventilation during exercise remains incompletely understood. Digoxin has been reported to increase chemoreflex sensitivity in humans. In the present randomized, cross-over, double-blind study, we tested the hypothesis that this increases the ventilatory response to exercise in normal subjects, as assessed ...
Bourdillon Nicolas - - 2009
Acute exposure to hypoxia provokes a decrease in peak oxygen consumption ( V(O)(2peak)). At and above 4000 m, the decrease in V(O)(2peak) is greater than expected from the decrease in arterial oxygen content (C(a)O(2)) suggesting the participation of other factors. We hypothesized that O(2) transfer within the active muscle may ...
Burtscher Martin - - 2010
Repeated short-term hypoxia (interval hypoxia) has been suggested to increase exercise tolerance by enhancing stress resistance and/or improving oxygen delivery. As low exercise tolerance contributes to mortality in patients with coronary artery disease (CAD) and chronic obstructive pulmonary disease (COPD), interval hypoxia might be a valuable preventive and therapeutic tool ...
Herigstad Mari - - 2009
This study is concerned with the pulmonary vasculature in euoxia after preconditioning with 8h of hypoxia. The particular question we ask is whether the pulmonary vasculature will dilate normally with exercise or retain some degree of vasoconstriction, as has previously been reported in studies involving longer exposures to the hypoxia ...
Dupont-Prinet A - - 2009
Previous studies have shown that if European sea bass are exercised after feeding, they can achieve a significantly higher maximum metabolic rate (MMR) than when fasted. They can meet combined metabolic demands of digestion (specific dynamic action, SDA) and maximal aerobic exercise, with no decline in swimming performance. If, however, ...
Wiesner Susanne - - 2010
Previous studies suggested that hypoxia and exercise may have a synergistic effect on cardiovascular and metabolic risk factors. We conducted a single blind study in overweight to obese subjects to test the hypothesis that training under hypoxia (HG, n = 24, FiO(2) = 15%) results in similar or even greater ...
Grünig Ekkehard - - 2009
This large, prospective, multicentric study was performed to analyze the distribution of tricuspid regurgitation velocity (TRV) values during exercise and hypoxia in relatives of patients with idiopathic and familial pulmonary arterial hypertension (PAH) and in healthy control subjects. We tested the hypothesis that relatives of idiopathic/familial PAH patients display an ...
Stickland Michael K - - 2009
Control of exercising muscle blood flow is a balance between local vasodilatory factors and the increase in global sympathetic vasoconstrictor outflow. Hypoxia has been shown to potentiate the muscle sympathetic nerve response to exercise, potentially limiting the increase in muscle blood flow. Accordingly, we investigated sympathetic restraint to exercising muscle ...
Bonetti Darrell L - - 2009
PURPOSE: Adaptation to acutely intermittent hypoxic exposure appears to produce worthwhile enhancements in endurance performance, but the current 5-min duration of hypoxia and recovery intervals may not be optimal. METHODS: Eighteen male competitive cyclists and triathletes were randomized to one of two intermittent-hypoxia groups, and nine similar athletes represented a ...
Qutub Amina A - - 2009
Vascular disease, cancer, stroke, neurodegeneration, diabetes, inflammation, asthma, obesity, arthritis--the list of conditions that involve angiogenesis reads like main chapters in a book on pathology. Angiogenesis, the growth of capillaries from preexisting vessels, also occurs in normal physiology, in response to exercise or in the process of wound healing.Why and ...
Richardson Alan - - 2009
Evidence of the effect of dehydration on physiological responses to hypoxia is limited. The purpose of this study was to determine the effect of hypohydration severity on physiological, renal hormonal and psychological responses to acute hypoxia. Eight males completed intermittent walking tests under normobaric hypoxic conditions (FI O(2) = 0.13) ...
Subudhi Andrew W - - 2009
Reductions in prefrontal oxygenation near maximal exertion may limit exercise performance by impairing executive functions that influence the decision to stop exercising; however, whether deoxygenation also occurs in motor regions that more directly affect central motor drive is unknown. Multichannel near-infrared spectroscopy was used to compare changes in prefrontal, premotor, ...
Amann Markus - - 2009
Aerobic exercise capacity decreases with exposure to hypoxia. This article focuses on the effects of hypoxia on nervous system function and the potential consequences for the exercising human. Emphasis is put on somatosensory muscle afferents due to their crucial role in the reflex inhibition of muscle activation and in cardiorespiratory ...
Calbet Jos? A L - - 2009
Hypoxia-induced hyperventilation is critical to improve blood oxygenation, particularly when the arterial Po2 lies in the steep region of the O2 dissociation curve of the hemoglobin (ODC). Hyperventilation increases alveolar Po2 and, by increasing pH, left shifts the ODC, increasing arterial saturation (Sao2) 6 to 12 percentage units. Pulmonary gas ...
Mauget-Faysse M - - 2009
PURPOSE: To determine if hypoxia tolerance in patients with retinal vein occlusion (RVO) following exposure to transient hypoxia is different from the hypoxia tolerance of healthy patients without retinal vein occlusion. METHODS: Consecutive patients presenting with RVO following exposure to transient hypoxia (Group I) were compared with healthy subjects (Group ...
Steinback Craig D - - 2009
We compared the integrated cardiovascular and autonomic responses to hypercapnia and hypoxia to test the hypothesis that these stimuli differentially affect muscle sympathetic nerve activity (MSNA) discharge patterns and cardiovagal and sympathetic baroreflex function in a manner related to ventilatory chemoreflex sensitivity. Six males and six females underwent 5 min ...
Sears Jonathan E - - 2008
Oxygen-induced retinopathy (OIR) in the mouse, like the analogous human disease retinopathy of prematurity, is an ischemic retinopathy dependent on oxygen-induced vascular obliteration. We tested the hypothesis that chemically overriding the oxygen-induced downregulation of hypoxia-inducible factor (HIF) activity would prevent vascular obliteration and subsequent pathologic neovascularization in the OIR model. ...
Calbet José A L - - 2009
Peak aerobic power in humans (VO2,peak) is markedly affected by inspired O2 tension (FIO2). The question to be answered in this study is what factor plays a major role in the limitation of muscle peak VO2 in hypoxia: arterial O2 partial pressure (Pa,O2) or O2 content (Ca,O2)? Thus, cardiac output ...
Bernasconi C J - - 2008
The effects of prolonged emersion (24, 48 and 72 h) and subsequent re-immersion on Nephrops norvegicus (L.) held at 5 degrees C were assessed using an index of physical quality criteria and a suite of haemolymph constituent assays. Collectively, these showed classical hypoxia-induced changes over 48 h of emersion, but, ...
Wang Baodong - - 2009
Based on the seasonal surveying data and long-term data, the annual changes in the geographical locations, occurrence frequency, affected areas and the minimum oxygen level as well as the formation mechanism of the summer hypoxia off the Changjiang estuary are summarized and discussed in this paper. The historical data indicates ...
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