Search Results
Results 101 - 150 of 793
1 2 3 4 5 6 7 8 9 10 >
Thorsen E - - 2006
Decompression stress and exposure to hyperoxia may cause a reduction in transfer factor of the lung for carbon monoxide and in maximal aerobic capacity after deep saturation dives. In this study lung function and exercise capacity were assessed before and after a helium-oxygen saturation dive to a pressure of 2.5 ...
Watanabe Yuuki - - 2006
Buoyancy is one of the primary external forces acting on air-breathing divers and it can affect their swimming energetics. Because the body composition of marine mammals (i.e. the relative amounts of lower-density lipid and higher-density lean tissue) varies individually and seasonally, their buoyancy also fluctuates widely, and individuals would be ...
Løset Are A - - 2006
INTRODUCTION: Recent studies have shown that a nitric oxide releasing agent or a single bout of high-intensity exercise 20-24 h before a dive can prevent bubble formation following decompression. The aim of this study was to determine whether high-intensity exercise immediately prior to a dive eliminates the protective effect of ...
Billeh Rana - - 2006
Differential efficacy of immediate-release metoprolol tartrate and carvedilol in the treatment of congestive heart failure remains a subject of ongoing debate. The degree of beta1-blockade can be assessed by percentage reduction of exercise heart rate. Twelve healthy subjects underwent symptom-limited cardiopulmonary exercise testing repeated weekly and 2 hours after randomized, ...
Manohar M - - 2006
REASON FOR PERFORMING STUDY: Work is required to establish the role of endogenous nitric oxide (NO) in metabolism of resting and exercising horses. OBJECTIVES: To examine the effects of NO synthase inhibition on O2 extraction and anaerobic metabolism at rest, and during submaximal and maximal exertion. METHODS: Placebo and NO ...
Dujić Zeljko - - 2006
PURPOSE: Prevention of bubble formation is a central goal in standard decompression procedures. Previously we have shown that exercise 20-24 h prior to a dive reduces bubble formation and increases survival in rats exposed to a simulated dive. Furthermore, we have demonstrated that nitric oxide (NO) may be involved in ...
Lanfranconi Francesca - - 2006
PURPOSE: The main aim of the present study was to investigate skeletal muscle oxidative metabolism in heart transplant recipients (HTR) by noninvasive tools. METHODS: Twenty male HTR (age 50.4 +/- 2.6 yr; mean +/- SE) and 17 healthy untrained age-matched controls (CTRL) performed an incremental exercise (IE) and a series ...
Møllerløkken A - - 2006
It has previously been reported that a nitric oxide (NO) donor reduces bubble formation from an air dive and that blocking NO production increases bubble formation. The present study was initiated to see whether a short-acting NO donor (glycerol trinitrate, 5 mg/ml; Nycomed Pharma) given immediately before start of decompression ...
Houssière Anne - - 2006
Peripheral chemoreflex inhibition with hyperoxia decreases sympathetic nerve traffic to muscle circulation [muscle sympathetic nerve activity (MSNA)]. Hyperoxia also decreases lactate production during exercise. However, hyperoxia markedly increases the activation of sensory endings in skeletal muscle in animal studies. We tested the hypothesis that hyperoxia increases the MSNA and mean ...
Arena Ross - - 2006
PURPOSE: The analysis of oxygen (O2) uptake on-kinetics at the onset of aerobic exercise has been shown to be reflective of cardiovascular and skeletal muscle health in a number of previous investigations. The purpose of the present investigation is to assess the short-term reliability of O2 uptake on-kinetics in a ...
Dodd Jonathan D - - 2006
PURPOSE: To evaluate whether thin-section chest computed tomographic (CT) findings correlate with exercise capacity, body mass index (BMI), dyspnea, and leg discomfort in patients with cystic fibrosis (CF). MATERIALS AND METHODS: Institutional ethics committee approval was obtained, and patients provided written informed consent. Twenty-two patients (13 male and nine female ...
Mathie Natalie J - - 2006
In aquatic vertebrates that acquire oxygen aerially dive duration scales positively with body mass, i.e. larger animals can dive for longer periods, however in bimodally respiring animals the relationship between dive duration and body mass is unclear. In this study we investigated the relationships between body size, aquatic respiration, and ...
Green J A - - 2008
The relationship between heart rate (f(H)) and rate of oxygen consumption (V(.)O2) was investigated under changing conditions of ambient temperature, digestive state and exercise state in the little penguin (Eudyptula minor). Both f(H) and V(.)O2 were recorded simultaneously from 12 little penguins while they each (a) rested and exercised within ...
Gonzalez Norberto C - - 2006
We previously showed that after seven generations of artificial selection of rats for running capacity, maximal O2 uptake (VO2max) was 12% greater in high-capacity (HCR) than in low-capacity runners (LCR). This difference was due exclusively to a greater O2 uptake and utilization by skeletal muscle of HCR, without differences between ...
Schmitt Laurent - - 2006
This study tested the effects of "living high-training low" (Hi-Lo) on aerobic performance and economy of work in elite athletes. Forty endurance athletes (cross-country skiers, swimmers, runners) performed 13-18 consecutive days of training at 1,200 m altitude, by sleeping at 1,200 m (LL, n = 20) or in hypoxic rooms ...
Butler Patrick J - - 2006
The original definition of aerobic dive limit (ADL) was the dive duration after which there is an increase in post-dive concentration of lactate in the blood of Weddell seals freely diving in the field. The only other species in which such measurements have been made is the emperor penguin. For ...
Ades Philip A - - 2006
BACKGROUND: Symptom-limited treadmill testing is commonly performed on entry to cardiac rehabilitation (CR) for its prognostic value and to design a safe and effective exercise program. Normative values for this evaluation are not available. The primary goals of this study were to establish normative values for peak aerobic capacity (peak ...
Dujić Zeljko - - 2006
INTRODUCTION: The effect of post-dive exercise on bubble formation remains controversial, although the current practice of divers and aviators is to avoid strenuous exercise after diving. Previously, we have shown that exercising 24 h before a dive, or during a decompression stop, significantly reduces bubble formation in man. The objective ...
Chim Harvey - - 2006
Severe acute respiratory syndrome (SARS) is a highly infectious, rapidly progressive, emerging disease. Early diagnosis and preventive measures are key for treatment and minimization of secondary spread. In the context of the armed forces, aggressive containment measures are essential to prevent an outbreak. In this study, we present the first ...
Poole David - - 2006
Healthy aging acts to redistribute blood flow (Q) and thus O2 delivery (QO2 ) among and within the exercising muscles such that QO2 to highly oxidative muscle fibers may be compromised. Within the microcirculation of old muscles capillary hemodynamics are altered and the matching of QO2 to oxidative requirements (VO2) ...
Morgan Allyson M - - 2006
A better understanding of the controls on algae and dissolved O2 in agricultural streams of Illinois is needed to aid in development of nutrient standards. We investigated the relationships between dissolved nutrients, algal abundance, and dissolved O2 in five streams in east-central Illinois from March through November 2004. The streams ...
Berger Nicolas J A - - 2006
The purpose of this study was to examine the influence of acute plasma volume expansion (APVE) on oxygen uptake (V(O2)) kinetics, V(O2peak), and time to exhaustion during severe-intensity exercise. Eight recreationally active men performed "step" cycle ergometer exercise tests at a work rate requiring 70% of the difference between the ...
Arieli Ran - - 2006
INTRODUCTION: Oxygen toxicity is a problem in diving and can have fatal consequences in the water. Various aspects of oxygen diving have been studied in dry hyperbaric chambers, but there is a lack of information on in-water diving using closed-circuit oxygen apparatus. METHOD: We collected 2527 dive reports from 473 ...
Chuang M-L - - 2006
BACKGROUND: The wide 95% confidence interval for S(a)O2 measured by pulse oximetry (S(P)O2) and the inherent characteristics of the oxyhaemoglobin dissociation curve can lead to modest but significant decreases in P(a)O2 (deltaP(a)O2 > or = 5 mmHg) that may be under-appreciated. AIM: To avoid missing potentially significant deltaP(a)O2 by using ...
Mündel Toby - - 2006
Nicotine is widely reported to increase alertness, improve co-ordination and enhance cognitive performance; however, to our knowledge there have been no attempts to replicate these findings in relation to exercise endurance. The purpose of this study was to determine the effects nicotine might have on cycling endurance, perception of exertion ...
Hindle A G - - 2006
We tested the hypothesis that immersion hypothermia enhances the diving capabilities of adult and juvenile muskrats by reducing rates of oxygen consumption (V O2). Declines in abdominal body temperature (T(b)) comparable to those observed in nature (0.5-3.5 degrees C) were induced by pre-chilling animals in 6 degrees C water. Pre-chilling ...
Dane D Merrill - - 2006
The spleen acts as an erythrocyte reservoir in highly aerobic species such as the dog and horse. Sympathetic-mediated splenic contraction during exercise reversibly enhances convective O2 transport by increasing hematocrit, blood volume, and O2-carrying capacity. Based on theoretical interactions between erythrocytes and capillary membrane (Hsia CCW, Johnson RL Jr, and ...
Xiao Guo Qiang - - 2006
Two groups, each containing 10 young healthy male students, participated in the study. One group breathed 70% O2 after exercise (70% O2 group) while the other group breathed normal air (Normal air group) after exercise. The results of the study show the following: (1) in both groups, the Monodehydyoxygenbate (MDA) ...
Yano T - - 2007
The purpose of the present study was to examine whether the level of oxygen uptake (V(.)(O2) at the onset of decrement-load exercise (DLE) is lower than that at the onset of constant-load exercise (CLE), since power output, which is the target of V(.)(O2) response, is decreased in DLE. CLE and ...
Chavko Mikulas - - 2006
Intermittent air breaks during hyperbaric oxygen (HBO2) exposures protect against pulmonary and central nervous system (CNS) toxicity. The mechanisms of this beneficial effect from intermittency are not known. In this study, we examined if release of vasoconstriction during HBO2 exposure indicates a threshold for toxic dose of HBO2 and how ...
Wei Hui - - 2006
In response to changes in phloem supply, adenylate demand, and oxygen status, legume nodules are known to exercise rapid (seconds to hours) physiological control over their permeability to oxygen diffusion. Diffusion models have attributed this permeability control to the reversible flow of water into or out of intercellular spaces. To ...
Amann Markus - - 2006
The effect of arterial O2 content (Ca(O2)) on quadriceps fatigue was assessed in healthy, trained male athletes. On separate days, eight participants completed three constant-workload trials on a bicycle ergometer at fixed workloads (314 +/- 13 W). The first trial was performed while the subjects breathed a hypoxic gas mixture ...
Kondratiev Timofei V - - 2006
It has been postulated that unsuccessful resuscitation of victims of accidental hypothermia is caused by insufficient tissue oxygenation. The aim of this study was to test whether inadequate O2 supply and/or malfunctioning O2 extraction occur during rewarming from deep/profound hypothermia of different duration. Three groups of rats (n = 7 ...
Stensrud T - - 2006
RATIONALE: Exercise-induced bronchoconstriction (EIB) increases in cold and dry air and decreases in humid air in subjects with asthma. Few reports have reported on the effect of humid environment upon exercise capacity in subjects with EIB. OBJECTIVE: The primary aim of the present study was to examine the effect of ...
Fahlman A - - 2006
A mathematical model was created that predicted blood and tissue N(2) tension (P(N2)) during breath-hold diving. Measured muscle P(N2) from the bottlenose dolphin after diving repeatedly to 100 m (Tursiops truncatus [Ridgway and Howard, 1979, Science, 4423, 1182-1183]) was compared with predictions from the model. Lung collapse was modelled as ...
Richardson Russell S - - 2006
Intracellular oxygen (O2) availability and the impact of ambient hypoxia have far reaching ramifications in terms of cell signalling and homeostasis; however, in vivo cellular oxygenation has been an elusive variable to assess. Within skeletal muscle the extent to which myoglobin desaturates (deoxy-Mb) and the extent of this desaturation in ...
Iwata Masato - - 2006
BACKGROUND: Recent evidence suggested that propofol can deteriorate the cerebral oxygen balance compared with inhalational anesthetics. However, dose-related influences of propofol on cerebral oxygen balances were not clearly investigated. In the current study, the authors investigated the effects of increasing concentrations of propofol on jugular venous bulb oxygen saturation (Sj(O2)) ...
Ferreira Leonardo F - - 2006
An increase in muscle contraction frequency could limit muscle blood flow QM compromising the matching of QM and muscle oxygen uptake VO2M. This study examined the effects of pedal cadence on skeletal muscle oxygenation at low, moderate and peak exercise. Nine healthy subjects [24.7+/-6.3 years (SD)] performed incremental cycling exercise ...
Barron John T - - 2005
Arteries stimulated by angiotensin II (AII) to contract do not display the expected augmentation of O2 consumption seen with other cardiovascular contractile agonists. We tested the hypothesis that superoxide (O2-) or other reactive oxidant species generated by AII played a role in the paradoxical O2 consumption response in porcine carotid ...
Wilkerson Daryl P - - 2006
The purpose of this study was to examine the influence of hyperoxic gas (50% O2 in N2) inspiration on pulmonary oxygen uptake (V(O2)) kinetics during step transitions to moderate, severe and supra-maximal intensity cycle exercise. Seven healthy male subjects completed repeat transitions to moderate (90% of the gas exchange threshold, ...
Parent Robert - - 2006
The long-term benefits of nitroglycerin (NTG) therapy are limited by the development of vascular tolerance and endothelial dysfunction in conductance coronary arteries. We have determined whether nitrate tolerance extends to NTG effects on myocardial O2 consumption (MV(O2)) and the ability of endogenous nitric oxide (NO) to modulate MV(O2) during exercise. ...
Gordos Matthew A - - 2006
Changes in heart rate (f(H)) and cloacal ventilation frequency (f(C)) were investigated in the Fitzroy turtle, Rheodytes leukops, under normoxic (17.85 kPa) and hypoxic (3.79 kPa) conditions at 25 degrees C. Given R. leukops' high reliance on aquatic respiration via the cloacal bursae, the objective of this study was to ...
Duscha Brian D - - 2005
STUDY OBJECTIVES: Although increasing aerobic fitness by exercise training is advocated as part of a healthy lifestyle, studies examining the different effects of intensity and amount on peak consumption (V(O2)) remain sparse. DESIGN: This randomized controlled trial compared the effects of three different exercise regimens differing in amount and intensity ...
Esaki Kazuki - - 2005
It is not clear whether muscle oxygenation (O(2-NIRS)) measured by near-infrared spectroscopy (NIRS) correlates with femoral venous SO2 (S(fv)o2) during normoxic exercise. Therefore, the purpose of this study was to compare physiologically calibrated O(2-NIRS) with S(fv)o2 in subjects performing one-legged dynamic knee extension exercise (1L-KEE). Five healthy male subjects (age ...
Thornton Sheila J - - 2005
The aim of this study was to examine the effect of forced diving on cardiac dynamics in a diving mammal by evaluating cardiac output and heart rate. We used MR Imaging and phase contrast flow analysis to obtain accurate flow measurements from the base of the aorta. Heart rate (fh) ...
Maeder Micha - - 2005
To test the performance of a tool designed to estimate functional capacity in order to select a bicycle ramp protocol yielding a test duration from 8 to 12 min in healthy individuals, and to assess differences in exercise responses between bicycle and treadmill tests. Forty-one healthy and physically active volunteers ...
Romer Lee M - - 2006
The effect of exercise-induced arterial hypoxemia (EIAH) on quadriceps muscle fatigue was assessed in 11 male endurance-trained subjects [peak O2 uptake (VO2 peak) = 56.4 +/- 2.8 ml x kg(-1) x min(-1); mean +/- SE]. Subjects exercised on a cycle ergometer at >or=90% VO2 peak) to exhaustion (13.2 +/- 0.8 ...
Marino Franca - - 2006
Migration and superoxide anion (O2-) generation were studied in polymorphonuclear leukocytes (PMNs) from 14 athyreotic patients, previously treated by total thyroidectomy and radioiodine therapy for differentiated thyroid carcinoma, and from age- and sex-matched euthyroid healthy controls. Patients were studied twice: in hypothyroidism (visit 1) and after TSH-suppressive L-T4 replacement therapy ...
Kemming Gregor I - - 2005
Perfluorocarbon (PFC) emulsions are intravascular oxygen therapeutics that temporarily enhance tissue oxygenation in dilutional anemia. However, PFC emulsions are not resuscitation fluids because PFCs only work optimally in the presence of high O2 partial pressure (hyperoxia); moreover, because they have no oncotic potential, dosing limitations prevent their use to permanently ...
Shykoff B E - - 2005
Elevated inspired oxygen partial pressures (PO2) may cause pulmonary oxygen toxicity (PO2T). However, normal variability and water immersion also cause pulmonary function (PF) changes. In 21 subjects, we measured the variability of flow-volume parameters and diffusing capacity for carbon monoxide (DLCO) for six weeks without diving. In 24 divers, we ...
1 2 3 4 5 6 7 8 9 10 >