Search Results
Results 601 - 650 of 1266
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Boone W T - - 1995
To determine if a 36-h fast affects the central and peripheral components of VO2 during submaximal exercise and peak oxygen uptake (VO2 peak), 10 physically healthy males exercised first for 10 min at approximately 60% of their VO2 peak and then to fatigue. Their cardiovascular responses were compared with those ...
Wilson J R - - 1995
OBJECTIVES: The purpose of this study was to determine how often peak exercise oxygen consumption (VO2) misclassifies the severity of cardiac dysfunction in potential heart transplant candidates. BACKGROUND: Cardiopulmonary exercise testing is being used to help select heart transplant candidates on the basis of the assumption that a low peak ...
Bonen A - - 1995
We compared the relationship between predicted VO2 max (ml kg-1min-1) and recreational exercise patterns, using secondary data analysis of a comprehensive national survey (18,293 subjects aged 15-69 years). Exercise participation and predicted VO2 max data were available for about 50% of this sample (4933 females, 4738 males). As expected, VO2 ...
Leyk D - - 1995
The adjustment of pulmonary oxygen uptake (VO2) following a step increase in work rate has been characterized as consisting of an early "cardiodynamic" component with unchanged mixed-venous O2-content ("phase 1") and a subsequent "metabolic" component ("phase 2") starting when venous blood from the muscle arrives at the lungs. The aim ...
Revelly J P - - 1995
OBJECTIVE: To determine whether, during hemorrhagic shock, the effect of epinephrine on energy metabolism could be deleterious, by enhancing the oxygen requirement at a given level of oxygen delivery (DO2). DESIGN: Prospective, randomized, control trial. SETTING: Experimental laboratory. SUBJECTS: Two groups of seven mongrel dogs were studied. The epinephrine group ...
Rundell K W - - 1995
Speed skaters have previously relied on cycle ergometry for physiological testing. Current evidence suggests skate-specific testing might be more appropriate. Unlike cycling, skating and off-ice low walk training involves a 'crouched' posture, placing the quadriceps in static contraction. This may compromise blood flow to working muscles and influence VO2. We ...
Kasch F W - - 1995
Various studies report a 0-22% per decade decline in circulatory function (VO2max) with advancing age. Twelve exercising men (E) were followed for 28 years, mean age 43 and 71 years, initial to final measurement, while 12 dropouts (C) detrained for 21 years, with a mean age from first to last ...
Pokan R - - 1995
In order to investigate the effect of an exercise protocol on the levelling-off O2 uptake and VO2 max values, ten male subjects aged 28 +/- 5 yrs, height 1.8 +/- 0.05 m, body mass 76 +/- 6 kg performed two treadmill exercise protocols: 1) constant grade (CG) of 5%, with ...
Gass E M - - 1995
The aim of the study was to compare the exercise responses during maximum wheelchair propulsion on a motor driven treadmill (TM) and maximum arm cranking (AC) in a homogenous group of nine paraplegic men with clinically complete spinal cord lesions between T4 and T6. The test order for each ergometer ...
Ye J M - - 1995
The Tasmanian bettong (Bettongia gaimardi) is a small marsupial rat kangaroo without detectable brown adipose tissue (BAT). The hindlimb was perfused with constant flow at 25 degrees C after cannulation under anesthesia of the femoral artery and vein to one hindlimb. Norepinephrine (NE, 25 nM-2.5 microM) and vasopressin (VP, 10 ...
Gray G L - - 1995
A common technique employed in flatwater kayak and canoe races is "wash riding", in which a paddler positions his/her boat on the wake of a leading boat and, at a strategic moment, drops off the wake to sprint ahead. It was hypothesized that this manoeuver was energy efficient, analogous to ...
Clark A L - - 1995
BACKGROUND: Adult patients with total correction of tetralogy of Fallot may have poor exercise capacity associated with impaired right heart function and in particular pulmonary regurgitation. The ventilatory responses to exercise were studied in a group of such patients to assess relations between ventilation, exercise capacity, and right ventricular function. ...
Lotgering F K - - 1995
In an effort to explore why CO2 output (VCO2) at peak exercise is lower during pregnancy than postpartum despite little change in the peak O2 uptake (VO2), we determined the VCO2/VO2 relationship during rapidly incremental exercise and estimated the anaerobic threshold (AT) and the respiratory compensation (RC) point. We measured ...
Green H J - - 1995
In previous studies we have been able to demonstrate tighter metabolic control of muscle metabolism during prolonged steady-state exercise 5 to 6 days after the initiation of training and well before changes in oxidative potential. To examine whether the metabolic adaptations are manifested during the non-steady-state adjustment to submaximal exercise, ...
Billat V - - 1995
The purpose of this study was to measure the running velocity corresponding to the individual maximal lactate steady-state of a group of 12-year old boys and girls on a treadmill. This running velocity (v MLST) was compared with the maximal aerobic running velocity (v a max) at which maximal oxygen ...
Belardinelli R - - 1995
We compared the slow rise in VO2 during heavy exercise (i.e., greater than lactic acidosis threshold (LAT)) with changes in muscle oxyhemoglobin+oxymyoglobin (O2Hb/O2Mb) saturation by reflectance near infrared spectroscopy. Ten subjects performed four 6-min cycle ergometer tests with two constant work rates less than and two greater than the LAT, ...
Koike A - - 1995
BACKGROUND: Symptom-limited incremental exercise tests are used to estimate the severity of cardiovascular disease and the patient's daily activity. However, there is a need for objective parameters for submaximal exercise. To test the hypothesis that a decrease in maximal exercise capacity can be estimated by oxygen uptake (VO2) kinetics, we ...
Patton J F - - 1995
While chemical protective (CP) clothing is known to adversely affect physical performance, few data exist regarding the physiological response of wearing US military CP clothing during incremental, dynamic exercise. To quantify the effects of CP clothing on energy cost and to test the hypothesis that the mask contributes little to ...
Reinhart K - - 1995
Hyperoxic ventilation, used to prevent hypoxemia during potential periods of hypoventilation, has been reported to paradoxically decrease whole body oxygen consumption (VO2). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O2 radical scavenger N-acetylcysteine ...
Bhambhani Y N - - 1995
This study examined the physiological responses during a 7.5-km simulated wheelchair race (SR) performed on rollers by 8 male quadriplegic marathon racers and analyzed the factors associated with SR time. Cardiac output (Q) was estimated during the SR using carbon dioxide rebreathing, from which stroke volume (SV) and (alpha-v)O2 diff ...
Unnithan V B - - 1995
With the increased use of oxygen consumption measurements in clinical and sporting studies, measurement variability has become more important to both the paediatric clinician and the sports scientist. In this study we assessed the reproducibility of cardiorespiratory measurements during submaximal and maximal running in children. Ten healthy, physically active boys ...
Jones M O - - 1995
Perioperative changes in heart rate (HR), respiratory rate (RR), physical activity, body temperature, oxygen consumption (VO2), carbon dioxide production (VCO2) and resting energy expenditure (REE) were studied in fourteen infants (weight 3.1 +/- 0.2 kg) who had a major operation. VO2 and VCO2 were measured by indirect calorimetry preoperatively, and ...
Fukuoka Y - - 1995
The purpose of this study was to evaluate the specificity of maximal oxygen uptake (VO2max) and the dynamic response of oxygen uptake (VO2) to sinusoidal work load in distance runners and in American-football players. Sinusoidal work load during ergometer cycling was carried from 30 W to 60% to VO2max (60% ...
Bottini P - - 1995
We investigated cardiovascular function and plasma catecholamine response during incremental exercise and recovery in diabetic patients with (DAN+) and without autonomic neuropathy (DAN-). The former group was divided according to the presence of parasympathetic (DAN+PH-) or associated parasympathetic and sympathetic (DAN+PH+) damage to the autonomic nervous system. A group of ...
Coyle E F - - 1995
This model is used to understand the interrelationships of the physiological factors determining endurance performance ability during prolonged exercise. Early studies found that marathon runners maintain a velocity in competition that corresponds to the intensity at which lactate begins to accumulate in blood and muscle [7, 8, 19]. From this ...
Colier W N - - 1995
The aim of this study was to determine oxygen consumption (VO2) during isometric exercise in human muscles using near infrared spectroscopy (NIRS). The technique was used to study the relationship between VO2 in the soleus muscle and the level of isometric exercise expressed as percentages of the maximum voluntary contraction ...
Ogita F - - 1995
To compare maximal cardio-respiratory stress between swim-bench exercise (SB) and arm stroke (AS), peak oxygen uptake (VO2peak) was measured in six trained swimmers. The SB was performed at stroke frequency of 50.min-1. Oxygen uptake (VO2) was measured during exercise at 3-min constant exercise intensities in SB and at 4-min constant ...
Manthous C A - - 1995
We measured oxygen consumption (VO2) during spontaneous breathing with continuous positive airway pressure (CPAP), assist control ventilation (AC), and control ventilation during muscle relaxation (AC-MR) in eight patients undergoing resuscitation from cardiopulmonary failure. VO2 decreased in all eight patients between CPAP and AC-MR; mean VO2 (255 +/- 92 ml/min) on ...
Liu Y - - 1995
On reaching the respiratory compensation point (RCP) during rapidly increasing incremental exercise, the ratio of minute ventilation (VE) to CO2 output (VCO2) rises, which coincides with changes of arterial partial pressure of carbon dioxide (PaCO2). Since PaCO2 changes can be monitored by transcutaneous partial pressure of carbon dioxide (PCO2,tc) RCP ...
Yano H - - 1995
Development-related changes in maximal oxygen uptake (VO2max) and work performance were examined in young sedentary rats 4-11 weeks after birth during exercise. The running speed to elicit VO2max increased from 4 to 8 weeks of age, whereas the exercise VO2max declined progressively. Therefore, the work performance during the developmental phase, ...
Francescato M P - - 1995
The energy cost of internal work and its relationships with lower limb mass and pedalling frequency were studied in four male subjects [age 22.2 (SD 1.5) years, body mass 81.0 (SD 5.1) kg, maximal O2 uptake (VO2max) above resting 3.06 (SD 0.4) l.min-1]. The subjects cycled at 40, 60, 80 ...
Kenny G P - - 1995
The purpose of this study was to evaluate the relationships between heart rate (fc), oxygen consumption (VO2), peak force and average force developed at the crank in response to submaximal exercise employing a racing bicycle which was attached to an ergometer (RE), ridden on a treadmill (TC) and ridden on ...
Takaki H - - 1995
Percutaneous transvenous mitral commissurotomy (PTMC) increases peak oxygen uptake (VO2) chronically, but not acutely, despite early symptomatic improvements. Analysis of transient VO2 responses to submaximal exercise (an exercise regimen more comparable to the patients' daily activities than that provided by maximal exercise testing), may be sensitive in detecting the acute ...
Stringer W - - 1995
Oxygen uptake (VO2) kinetics have been reported to be modified when lactic acid accumulates; however little attention has been given to the simultaneous carbon dioxide production (VCO2) kinetics. To demonstrate how VCO2 changes as a function of VO2 when lactic acid is buffered by bicarbonate, eight healthy subjects performed 6-min ...
Chamari K - - 1995
To investigate pulmonary gas exchange and ventilatory responses to brief intense intermittent exercise and to study the effects of physical fitness on these responses, nine trained and nine untrained healthy male subjects aged 18-33 years performed the force-velocity (F-v) exercise test. This test consisted of 6-s sprints against increasing braking ...
Fukuba Y - - 1994
We examined the effect of two different slope protocols to the reproducibility of the VO2-VCO2 relationship and the lactic acidosis threshold (LAT) during incremental exercise. Two adult male subjects performed a cycle ergometer exercise 2 to 4 times repeatedly in which the increase of work rate was 25 W every ...
Shoemaker J K - - 1994
The kinetics of femoral artery mean blood velocity (MBV; measured by pulsed Doppler) and whole body oxygen uptake (VO2; measured breath by breath) were assessed from the time constant during the on (tau on) and off (tau off) transients to step changes in work rate between complete rest and dynamic ...
Gaesser G A - - 1994
For constant-load, heavy exercise (i.e., above the lactate threshold (TLac)), a slow component of oxygen uptake (VO2) is observed. Endurance training reduces the magnitude of the slow component and, hence, end-exercise VO2. Reductions in exercise VO2 have been reported after 7-8 wk of training; unpublished observations suggest that the VO2 ...
Whipp B J - - 1994
During constant-load exercise of moderate intensity, pulmonary O2 uptake (VO2) is characterized by two temporal response components. The first occurs during the transit delay from the exercising limbs and is mediated predominantly by increased pulmonary blood flow. Thereafter, this response is supplemented by the influence of increased O2 extraction, causing ...
Poole D C - - 1994
This paper offers a brief synopsis of the five preceding papers which constitute the proceedings of the symposium "Mechanistic basis of the slow component of VO2 kinetics during heavy exercise." The key features have been taken from each paper and a coherent position regarding the site and potential underlying mechanisms ...
Barstow T J - - 1994
Characterizing oxygen uptake (VO2) kinetics yields valuable information regarding both a) the effectiveness of the coupling of O2 delivery to tissue metabolic demands, and b) the ability of the muscle itself to utilize O2 for oxidative phosphorylation. During moderate exercise VO2 reaches a new steady state within 3 min in ...
Poole D C - - 1994
This paper: 1) Reviews evidence for the location of the slow component of VO2 kinetics either within the exercising limbs or alternatively at some site in the rest of the body, e.g., ventilatory, cardiac or accessory muscles. 2) Presents evidence in support of both the fast and slow components (i.e., ...
Koike A - - 1994
BACKGROUND: Resting cardiac function does not necessarily affect exercise capacity. However, to determine whether it affects early dynamics of oxygen uptake (VO2) during exercise, we measured VO2 during a constant work rate and during incremental exercise testing in patients with a history of myocardial infarction. VO2 kinetics and exercise capacity ...
Gaesser G A - - 1994
We tested the hypothesis that infused epinephrine (Epi) would augment the slow phase of oxygen uptake (VO2) during heavy exercise. Six normal healthy males initially performed a ramp test on a cycle ergometer to estimate the lactate threshold (LT) and determine peak VO2. Each subject then performed two 20-min constant-load ...
Yoshida T - - 1994
1. We determined the kinetics of cardiac output (Q) with respect to oxygen uptake (VO2) at the on- and off-transients of constant-load exercise. Six subjects performed constant-load exercise which consisted of 5 min rest, 5 min one-legged pedalling at 50 W and a 5 min recovery period. 2. The transient ...
Hoffman M D - - 1994
The physiological responses to treadmill roller skiing with the double pole (DP) and diagonal stride (DS) techniques were compared at 1.7% and 7.1% grades among eight cross-country ski racers. Oxygen uptake (VO2) requirements were found to be lower (P < 0.05) for DP at the 1.7% grade, but similar at ...
Rozé J C - - 1994
Measurements of oxygen uptake (VO2) and CO2 output (VCO2) are useful in critically ill patients. However, VO2 is not routinely measured in intensive care during mechanical ventilation (MV) especially in premature newborns. The present study describes a new method of measuring VO2 and VCO2 using a double open circuit which ...
Cox G - - 1994
This study examined the influence of sodium citrate on changes in selected blood, ventilatory and performance variables in response to intermittent sprint exercise. Eight moderately active male students completed three tests over a 6 day experimental period. The first test involved incremental exercise to determine VO2 max, while the second ...
Kooyman G L - - 1994
Oxygen consumption (VO2), heart rate and blood chemistry were measured in four emperor penguins, Aptenodytes forsteri (Gray), during graded swimming exercise. The maximum VO2 obtained, 52 ml O2 kg-1 min-1, was 7.8 times the measured resting VO2 of 6.7 ml O2 kg-1 min-1 and 9.1 times the predicted resting VO2. ...
Paterson D H - - 1994
Our purpose was to examine the gas exchange response to exercise in heart transplant (HT) patients and to characterize the O2 uptake kinetics (tau VO2) during successive square-wave on-transients from loadless cycling to moderate exercise. We hypothesized that with a slow heart rate response (and O2 transport limitation) O2 kinetics ...
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