New technology allows cyclists to train via power output (PO) in addition to heart rate (HR). For those athletes undertaking seasonal laboratory testing (e.g., Vo(2), lactate threshold), it is imperative that athletes be able to directly apply this information to their training device. We examined the reliability of a standardized ...

The present study was conducted to examine (a) whether there is an association between maximal oxygen uptake (Vo(2)max) and reduction in postexercise heart rate (HR) and blood lactate concentrations ([La]) following resistance exercise and (b) how intensity and Volume of resistance exercise affect postexercise Vo(2). Eleven regularly weight-trained males (20.8 ...

Cordyceps sinensis (Cs) and Rhodiola rosea (Rr) are herbs used in traditional Chinese medicine to treat a multitude of ailments as well as to enhance performance. The purpose of this research was to examine the effects of a formula containing Cs and Rr (Cs-Rr) on circulatory dynamics, specifically muscle tissue ...

OBJECTIVES: Primary pulmonary hypertension (PPH) is a pulmonary vasculopathy resulting in exercise intolerance, usually due to dyspnea. We hypothesized that ventilation is increased during exercise in PPH relative to normal because the ventilated lung is underperfused, cardiac output increase is restricted, and arterial hypoxemia may develop. Our aim was to ...

OBJECTIVES: To clarify (1) differences in cardiovascular response during low-intensity exercise in the upright versus the recumbent position, and (2) whether the oxygen uptake (V o 2 ) calculated by the American College of Sports Medicine (ACSM) metabolic equation reflects the actual V o 2 at low-intensity testing. DESIGN: Repeated-measures ...

We tested the hypothesis that time course of O (2) uptake (VO (2)) measured during a supramaximal exercise performed in the field is driven to maximal oxygen uptake (VO (2max)). On an outdoor track, five middle-distance male runners first performed a test to determine VO (2max) and a supramaximal 800-m ...

BACKGROUND: Neuromuscular symptoms and impaired muscle energy metabolism have been described in subclinical hypothyroidism (sHT). AIM: The aim of the study was to evaluate the energy and substrate response to exercise in sHT patients using a standardized protocol and to test the effect of L-T(4) replacement in a double-blind, randomized, ...

CONTEXT: The impact of progestins on exercise performance in women has not been previously studied. OBJECTIVE: The objective of this study was to examine the effect of a synthetic progestin on aspects of exercise status in young women. DESIGN, PATIENTS, SETTING: Twenty-three young, healthy, habitually sedentary women participated in a ...

The purpose of this study was to assess the validity of predicting maximal oxygen uptake(VO(2max)) from sub-maximal VO(2) values elicited during a perceptually-regulated exercise test. We hypothesised that the strong relationship between the ratings of perceived exertion (RPE) and VO(2) would enable VO(2max) to be predicted and that this would ...

OBJECTIVE AND METHODS: A cohort of 100 patients with unexplained chronic fatigue (CF) was assessed longitudinally for 1.5 years to determine if physical activity (kcal expended), exercise capacity (VO(2)max), perceived exertion, and body mass index (BMI) changed over time and were associated with changes in CF-related clinical status. RESULTS: BMI ...

OBJECTIVE: To investigate the repeatability and criterion related validity of the 20 m multistage fitness test (MFT) for predicting maximal oxygen uptake (Vo(2max)) in active young men. METHODS: Data were gathered from two phases using 30 subjects (x+/-s; age = 21.8+/-3.6 years, mass = 76.9+/-10.7 kg, stature = 1.76+/-0.05 m). ...

Traditionally, it has been accepted that, during incremental exercise, stroke volume plateaus at 40% of Vo(2)max. However, recent research has documented that stroke volume progressively increases to Vo(2)max in both trained and untrained subjects. The stroke volume response to incremental exercise to Vo(2)max may be influenced by training status, age, ...

BACKGROUND: Exertional dyspnea is a frequent limiting symptom in patients with chronic heart failure. Furthermore, dyspnea and a plateau in VO(2) (oxygen consumption) at peak exercise often co-exist in chronic heart failure, especially in patients with severe regurgitant valvular heart disease (RVHD), their relevance to hemodynamics and subjective symptoms during ...

This case describes the physiological maturation from ages 21 to 28 yr of the bicyclist who has now become the six-time consecutive Grand Champion of the Tour de France, at ages 27-32 yr. Maximal oxygen uptake (Vo(2 max)) in the trained state remained at approximately 6 l/min, lean body weight ...

The present study examined the role of the cytokine IL-6 in the regulation of fatty acid metabolism during exercise in humans. Six well-trained males completed three trials of 120 min of cycle ergometry at 70% peak O(2) consumption (Vo(2 peak); MOD) and 40% Vo(2 peak) with (LOW + IL-6) and ...

The Fick equation holds that oxygen uptake (Vo(2)) is the product of cardiac output and arterial venous oxygen difference. Factors limiting Vo(2) (ie, maximal Vo(2)) with exercise have therefore been traditionally sought within the determinants of cardiac function. However, such an approach ignores a large body of research evidence indicating ...

Parra et al. (Acta Physiol. Scand 169: 157-165, 2000) showed that 2 wk of daily sprint interval training (SIT) increased citrate synthase (CS) maximal activity but did not change "anaerobic" work capacity, possibly because of chronic fatigue induced by daily training. The effect of fewer SIT sessions on muscle oxidative ...

INTRODUCTION: Noninvasive estimates of Paco(2) are usually done by measuring exhaled carbon dioxide at end-expiration (Petco(2)). While commonly used in studies involving healthy patients, it is less useful in sicker patients. Conditions that affect the terminal dead space and hence the accuracy of Petco(2) as a surrogate for Paco(2) may ...

STUDY OBJECTIVES: To identify the following in individuals with chronic stroke: (1) the relationship between the maximal oxygen consumption (Vo(2)max) during cycle ergometry and the distance covered in the 6-min walk test (6MWT), and (2) the stroke-specific impairments that are important determinants for the 6MWT distance. DESIGN: Cross-sectional study using ...

PURPOSE: Eight recreational and eight competitive athletes were studied to determine the cardiovascular and musculoskeletal effects of running in hypergravity conditions simulated by the use of lower body negative pressure (LBNP). Subjects are sealed in a LBNP chamber with the use of a flexible, neoprene waist seal and the chamber ...

INTRODUCTION/PURPOSE: This study investigated whether the progressive rise in heart rate (HR) and fall in stroke volume (SV) during prolonged, constant-rate, moderate-intensity exercise (cardiovascular drift, CVdrift) in a hot environment is associated with a reduction in VO(2max). METHODS: CVdrift was measured in nine male cyclists between 15 and 45 min ...

In older healthy men, aerobic exercise capacity is related to postischemic flow-mediated dilation of the brachial artery (FMD), but corresponding data in a younger population is not available. In addition, whether submaximal aerobic exercise performance also correlates with this kind of vasomotor reactivity is not known. Therefore, in 15 nonsmoking ...

It has been suggested that skeletal muscle O(2) uptake (Vo(2)) kinetics follow a first-order control model. Consistent with that, Vo(2) should show both 1) similar onset kinetics and 2) an on-off symmetry across submaximal work intensities regardless of the metabolic perturbation. To date, consensus on this issue has not been ...

The near-infrared spectroscopy (NIRS) signal (deoxyhemoglobin concentration; [HHb]) reflects the dynamic balance between muscle capillary blood flow (Q(cap)) and muscle O(2) uptake (Vo(2)(m)) in the microcirculation. The purposes of the present study were to estimate the time course of Q(cap) from the kinetics of the primary component of pulmonary O(2) ...

The purpose was to examine the adaptation of pulmonary O(2) uptake (Vo(2p)) and deoxygenation of the vastus lateralis muscle at the onset of heavy-intensity, constant-load cycling exercise in young (Y; 24 +/- 4 yr; mean +/- SD; n = 5) and older (O; 68 +/- 3 yr; n = 6) ...

Trans-sodium crocetinate (TSC), the isomer of the carotenoid compound crocetin, is found markedly to increase survival in hemorrhagic shock subsequent to 50-60% blood loss, mainly via restored resting oxygen consumption (VO(2)), blood pressure and heart rate. The proposed mechanism is that TSC increases oxygen diffusivity, and thus availability, in plasma. ...

BACKGROUND AND OBJECTIVES: Maximum oxygen uptake (VO(2) max) is internationally accepted parameter to evaluate the cardiorespiratory fitness. But determination of VO(2)max is restricted within well equipped laboratory because of its exhausting, hazardous and complicated experimental protocol. Various attempts have been made to enumerate indirect and easy protocols for prediction of ...

PURPOSE: There are conflicting reports on the kinetics of oxygen uptake at the onset of exercise in patients with cystic fibrosis (CF). The objective of the present study was, therefore, to compare oxygen uptake (VO(2) kinetics in patients with CF with those of healthy controls (CON). METHODS: Eighteen CF patients ...

PURPOSE: The purpose of this study was to determine the physiological responses of sedentary and endurance-trained female subjects during maximal exercise at different levels of acute hypoxia. METHODS: Fourteen women who were sea level residents were divided into two groups according to their level of fitness: 1) endurance-trained women (TW) ...

The purpose of this study was to compare the kinetics of oxygen uptake (VO(2)) during arm cranking with the legs inactive or exercising. Each subject (n = 8) performed three exercise protocols: 6-min arm cranking at an intensity of 60% of peak oxygen uptake (VO(2peak), AC(60)) and 6-min combined arm ...

The respiratory exchange ratio (RER) is a valid method for determining fat and carbohydrate oxidation during exercise when the exchange of respiratory gas is in a state of steady flux between the tissue and fluid compartments and the alveoli. However, under incremental intensity or heavy exercise conditions, the movement of ...

The balance between the capacities of RuBP (ribulose-1,5-bisphosphate) carboxylation (V(cmax)) and RuBP regeneration (expressed as the maximum electron transport rate, J(max)) determines the CO(2) dependence of the photosynthetic rate. As it has been suggested that this balance changes depending on the growth temperature, the hypothesis that the seasonal change in ...

BACKGROUND: A recommended component of heart transplant recipients (HTR) is endurance-oriented exercise therapy. However, the trainability of HTR after transplantation is vague. We examined the effect of high-volume and -intensity exercise training on exercise performance in HTR, compared with HTR undergoing regular rehabilitation training, and sedentary healthy subjects (SHS). METHODS: ...

Published literature asserts that cardiac output (Q(.) = V(.) >O(2)x1/C((a-v))O(2)) increases as a linear function of oxygen uptake with a slope of approximately 5-6 during constant work rate exercise. However, we have previously demonstrated that C((a-v))O(2) has a linear relationship as a function of V(.)O(2) during progressively increasing work rate ...

The purpose of this study was to compare O(2) uptake ((.)VO(2)) and muscle electromyography activity kinetics during moderate and severe exercise to test the hypothesis of progressive recruitment of fast-twitch fibers in the explanation of the VO(2) slow component. After an incremental test to exhaustion, 7 trained cyclists (mean +/- ...

AIM: Exercise induced arterial hypoxemia (EIAH) is a reduction in arterial oxygenation, which may result from a drop in arterial oxygen pressure and therefore in oxygen saturation. We examined EIAH in swimmers, while till now it was known to occur in cyclists and runners. METHODS: We studied 8 male highly ...

Previous studies of biomechanical efficiency (external work/energy input--Watt/O(2) consumed) in heart failure (HF) using cardiopulmonary exercise testing (CPET) and magnetic resonance spectroscopy (MRS) have had discordant results with increased efficiency by CPET and decreased efficiency by MRS. Compare biomechanical efficiency of HF subjects and normal controls during steady state (SS=35 ...

The dose contribution of (10)B(n,alpha)(7)Li reaction in BNCT using near threshold (7)Li(p,n)(7)Be direct neutrons can be increased through the use of materials referred to as boron-dose enhancers (BDE). In this paper, possible BDE optimization criteria were determined from the characteristics of candidate BDE materials namely (C(2)H(4))(n), (C(2)H(3)F)(n), (C(2)H(2)F(2))(n), (C(2)HF(3))(n), (C(2)D(4))(n), ...

The purpose of this study was to apply the session rating of perceived exertion (RPE) method, which is known to work with aerobic training, to resistance training. Ten men (26.1 +/- 10.2 years) and 10 women (22.2 +/- 1.8 years), habituated to both aerobic and resistance training, performed 3 x ...

The purpose of this investigation was to determine the level of cardiovascular stress elicited by continuous and prolonged circuit resistance training (CRT). Each of the 11 men who volunteered as a subject were tested to determine oxygen consumption and heart rate responses to a submaximal and maximal treadmill protocol and ...

The present study investigated the effect of preexercise metabolic alkalosis on the primary component of oxygen uptake (Vo(2)) kinetics, characterized by tau(1). Seven healthy physically active nonsmoking men, aged 22.4 +/- 1.8 (mean +/- SD) yr, maximum Vo(2) (Vo(2 max)) 50.4 +/- 4 ml.min(-1).kg(-1), performed two bouts of cycling, corresponding ...

We investigated whether dynamic cerebral autoregulation is affected by exhaustive exercise using transfer-function gain and phase shift between oscillations in mean arterial pressure (MAP) and middle cerebral artery (MCA) mean blood flow velocity (V(mean)). Seven subjects were instrumented with a brachial artery catheter for measurement of MAP and determination of ...

The stability of arterial PCO(2) (P(a)CO(2)) during moderate exercise in humans suggests a CO(2)-linked control that matches ventilation (V(E)) to pulmonary CO(2) clearance (VCO(2)). An alternative view is that V(E) is subject to long-term modulation (LTM) induced by "hyperpnoeic history". LTM has been reported with associative conditioning via dead-space (V(D)) ...

The arteriovenous oxygen difference (a-vO(2) difference), a measure of peripheral muscle oxygen extraction-utilization during exercise, is reduced in antiretroviral-treated patients with human immunodeficiency virus (HIV), thus causing a shift in the cardiac output-oxygen consumption (Q-VO(2)) relationship. We investigated the impact of recombinant human GH (rhGH) treatment on a-vO(2) difference and ...

OBJECTIVES: The respiratory compensation point (RCP) marks the onset of hyperventilation ("respiratory compensation") during incremental exercise. Its physiological meaning has not yet been definitely determined, but the most common explanation is a failure of the body's buffering mechanisms which leads to metabolic (lactic) acidosis. It was intended to test this ...

OBJECTIVE: To determine if stroke patients without specific aerobic training experience a change in the first 6 months after stroke. DESIGN: Descriptive, longitudinal study with repeated measures of exercise capacity at 1, 2, 3, and 6 months after stroke. SETTING: Exercise testing laboratory in a tertiary care hospital. PARTICIPANTS: Consecutive ...

The major avenues of extrapulmonary oxygen uptake were determined on submerged western painted turtles (Chrysemys picta bellii) at 10 degrees C by selectively blocking one or more potential pathways for exchange. Previous work indicated that the skin, the cloaca, and the buccopharyngeal cavity can all contribute significantly in various species ...

STUDY OBJECTIVES: To compare the effect of montelukast and the long-acting beta(2)-agonist salmeterol on cardiopulmonary exercise economy and physical performance in adult patients with asthma during exercise. DESIGN AND PATIENTS: Asthmatic patients (n = 18), aged 18 to 35 years with exercise-induced bronchoconstriction (EIB), using a double-blind, double-dummy cross-over design. ...

BACKGROUND: Exercise capacity, assessed by cardiopulmonary exercise treadmill testing (CPET), does not return to normal following heart transplantation. This study evaluated the ventilatory response to exercise and the kinetics of oxygen (O(2)) recovery in heart transplant recipients (HTR) compared to healthy volunteers (HV) and heart failure patients. METHODS: Eighteen patients ...

It has recently been reported that the 'gain' of Phase II increase in pulmonary oxygen uptake (i.e. the 'fundamental' increase in V(O(2)) per unit increase in work rate; G(p)) does not attain the anticipated value of approximately 10 ml min(-1)W(-1) following the onset of high-intensity exercise. In the present study, ...