Is there a disassociation of maximal oxygen consumption and maximal cardiac output?

2001 ◽  
Vol 33 (8) ◽  
pp. 1265-1269 ◽  
Author(s):  
STEVE D. MCCOLE ◽  
ALLISON M. DAVIS ◽  
PATRICK T. FUEGER
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Maximal Oxygen Consumption ◽  
Maximal Cardiac Output

Effect of small vs large muscle mass endurance training on maximal oxygen uptake in organ transplanted recipients

2021 ◽  
pp. 1-10
Author(s):  
Alessio del Torto ◽  
Carlo Capelli ◽  
Roberto Peressutti ◽  
Adriana di Silvestre ◽  
Ugolino Livi ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Endurance Training ◽  
Maximal Oxygen Consumption ◽  
Factors Affecting ◽  
Maximal Cardiac Output ◽  
Leg Cycling ◽  
Before And After ◽  
Large Muscle

Maximal oxygen consumption (V̇O2max) is impaired in heart (HTx), kidney (KTx), and liver (LTx) transplanted recipients and the contribution of the cardiovascular, central, and peripheral (muscular) factors in affecting V̇O2max improvement after endurance training (ET) has never been quantified in these patients. ET protocols involving single leg cycling (SL) elicit larger improvements of the peripheral factors affecting O2 diffusion and utilization than the double leg (DL) cycling ET. Therefore, this study aimed to compare the effects of SL-ET vs DL-ET on V̇O2max. We determined the DL-V̇O2max and maximal cardiac output before and after 24 SL-ET vs DL-ET sessions on 33 patients (HTx = 13, KTx = 11 and LTx = 9). The DL-V̇O2max increased by 13.8% ± 8.7 (p < 0.001) following the SL-ET, due to a larger maximal O2 systemic extraction; meanwhile, V̇O2max in DL-ET increased by 18.6% ± 12.7 (p < 0.001) because of concomitant central and peripheral adaptations. We speculate that in transplanted recipients, SL-ET is as effective as DL-ET to improve V̇O2max and that the impaired peripheral O2 extraction and/or utilization play an important role in limiting V̇O2max in these types of patients. Novelty: SL-ET increases V̇O2max in transplanted recipients because of improved peripheral O2 extraction and/or utilization. SL-ET is as successful as DL-ET to improve the cardiorespiratory fitness in transplanted recipients. The model of V̇O2max limitation indicates the peripheral factors as a remarkable limitation to the V̇O2max in these patients.

Heart size and maximal cardiac output are limited by the pericardium

1992 ◽  
Vol 263 (6) ◽  
pp. H1675-H1681 ◽  
Author(s):  
H. K. Hammond ◽  
F. C. White ◽  
V. Bhargava ◽  
R. Shabetai
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Diastolic Pressure ◽  
Maximal Oxygen Consumption ◽  
Left Ventricular ◽  
Treadmill Running ◽  
Oxygen Utilization ◽  
End Diastolic Volume ◽  
Maximal Cardiac Output ◽  
Heart Size

We tested the hypothesis that the pericardium, by restricting heart size, limits maximal cardiac output and oxygen consumption. We studied 15 pigs. Five underwent maximal treadmill running before and 14–21 days after thoracotomy and pericardiectomy; these pigs also received sequential volume infusions to determine end-diastolic pressure-dimension relationships. Five underwent maximal treadmill running before and 14–21 days after thoracotomy (pericardium undisturbed) to determine the effect of thoracotomy on exercise performance. Finally, five underwent thoracotomy, instrumentation, loose closure of the pericardium, and sequential volume infusions to determine the effect of thoracotomy without pericardiectomy on end-diastolic pressure-dimension relationships. Pericardiectomy caused similar increases in maximal cardiac output (29% increase; P = 0.007) and maximal oxygen consumption (31% increase; P = 0.02). These results were associated with increased left ventricular end-diastolic dimension (10% increase; P = 0.01) and an estimated 33% increase in end-diastolic volume. In addition, left ventricular mass was increased by pericardiectomy (18% increase; P < 0.04). Thus the pericardium, by limiting utilization of the Starling mechanism, limits maximal cardiac output, and the limit to cardiorespiratory performance lies not in oxygen utilization, but in oxygen delivery. Furthermore, removal of pericardium is associated with myocardial hypertrophy.

scholarly journals The effect of pericardiectomy on maximal oxygen consumption and maximal cardiac output in untrained dogs.

1986 ◽  
Vol 58 (4) ◽  
pp. 523-530 ◽  
Author(s):  
J Stray-Gundersen ◽  
T I Musch ◽  
G C Haidet ◽  
D P Swain ◽  
G A Ordway ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Maximal Oxygen Consumption ◽  
Maximal Cardiac Output

Physiological factors associated with the lower maximal oxygen consumption of master runners

1989 ◽  
Vol 66 (2) ◽  
pp. 949-954 ◽  
Author(s):  
A. M. Rivera ◽  
A. E. Pels ◽  
S. P. Sady ◽  
M. A. Sady ◽  
E. M. Cullinane ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Maximal Oxygen Consumption ◽  
Maximal Heart Rate ◽  
Distance Runners ◽  
Physiological Factors ◽  
Factors Associated ◽  
Older Athletes ◽  
Maximal Cardiac Output

We examined the hemodynamic factors associated with the lower maximal O2 consumption (VO2max) in older formerly elite distance runners. Heart rate and VO2 were measured during submaximal and maximal treadmill exercise in 11 master [66 +/- 8 (SD) yr] and 11 young (32 +/- 5 yr) male runners. Cardiac output was determined using acetylene rebreathing at 30, 50, 70, and 85% VO2max. Maximal cardiac output was estimated using submaximal stroke volume and maximal heart rate. VO2max was 36% lower in master runners (45.0 +/- 6.9 vs. 70.4 +/- 8.0 ml.kg-1.min-1, P less than or equal to 0.05), because of both a lower maximal cardiac output (18.2 +/- 3.5 vs. 25.4 +/- 1.7 l.min-1) and arteriovenous O2 difference (16.6 +/- 1.6 vs. 18.7 +/- 1.4 ml O2.100 ml blood-1, P less than or equal to 0.05). Reduced maximal heart rate (154.4 +/- 17.4 vs. 185 +/- 5.8 beats.min-1) and stroke volume (117.1 +/- 16.1 vs. 137.2 +/- 8.7 ml.beat-1) contributed to the lower cardiac output in the older athletes (P less than or equal 0.05). These data indicate that VO2max is lower in master runners because of a diminished capacity to deliver and extract O2 during exercise.

Increased capacity for circulatory fatty acid transport in a highly aerobic mammal

1994 ◽  
Vol 266 (4) ◽  
pp. R1280-R1286 ◽  
Author(s):  
G. McClelland ◽  
G. Zwingelstein ◽  
C. R. Taylor ◽  
J. M. Weber
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Fatty Acid ◽  
Maximal Oxygen Consumption ◽  
Fatty Acid Transport ◽  
Plasma Fatty Acid ◽  
In Vitro Experiments ◽  
Acid Transport ◽  
Positive Effect

Plasma fatty acid (FA) and albumin concentrations, cardiac output, and hematocrit of dogs and goats [dog-to-goat ratio of maximal oxygen consumption (VO2max) = 2.2] were measured to determine rates of circulatory FA delivery during exercise. Our goals were 1) to characterize the mechanism(s) used by the endurance-adapted species (dog) to support higher rates of FA delivery to working muscles than the sedentary species (goat) and 2) to determine whether circulatory transport is scaled with VO2max. Lipid oxidation was 2.5 times higher in dogs than in goats. Dogs had higher cardiac outputs than goats, but this positive effect on their FA delivery was canceled by higher hematocrit. Dogs always had higher plasma FA concentrations than goats. In contrast, albumin was steady and identical in both species, showing that dogs transport FA at higher rates than goats only because they load more FA on their albumin. Average dog-to-goat ratios for FA delivery (1.5-2.0) were lower than would be expected if this rate were scaled with VO2max. In vitro experiments showed that dog albumin is designed for high rates of FA transport because it can bind 50% more FA than goat albumin. All endurance-adapted species may possess such "aerobic albumins" to supply more circulating FA to their working muscles than sedentary species.

Cardiovascular hemodynamics with increasing exercise intensities in postmenopausal women

1999 ◽  
Vol 87 (6) ◽  
pp. 2334-2340 ◽  
Author(s):  
Steve D. McCole ◽  
Michael D. Brown ◽  
Geoffrey E. Moore ◽  
Joseph M. Zmuda ◽  
Jeffrey D. Cwynar ◽  
...  
Keyword(s):  
Physical Activity ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Postmenopausal Women ◽  
Exercise Intensity ◽  
Maximal Oxygen Consumption ◽  
Activity Levels ◽  
Physically Active ◽  
Cardiovascular Hemodynamics ◽  
Physical Activity Levels

We sought to determine the cardiovascular responses to increasing exercise intensities in postmenopausal women with different physical activity levels and hormone replacement therapy (HRT) status. Forty-four women (11 sedentary, 19 physically active, 14 master athletes; 24 not on HRT, 20 on HRT) completed treadmill exercise at 40, 60, 80, and 100% of maximal oxygen consumption. Oxygen consumption, heart rate, blood pressure, and cardiac output, determined via acetylene rebreathing, were measured at each exercise intensity. HRT did not affect cardiovascular hemodynamics. Stroke volume (SV) decreased significantly between 40 and 100% of maximal oxygen consumption in all groups, and the decrease did not differ among groups. The greater oxygen consumption of the athletes at each intensity was due to their significantly greater cardiac output, which was the result of a significantly greater SV, compared with both of the less active groups. The athletes had significantly lower total peripheral resistance at each exercise intensity than did the two less active groups. There were no consistent significant hemodynamic differences between the physically active and sedentary women. These results indicate that SV decreases in postmenopausal women as exercise intensity increases to maximum, regardless of their habitual physical activity levels or HRT status.

Hemodynamic and metabolic responses to self-paced and ramp-graded exercise testing protocols

2018 ◽  
Vol 43 (6) ◽  
pp. 609-616 ◽  
Author(s):  
Nicholas M. Beltz ◽  
Fabiano T. Amorim ◽  
Ann L. Gibson ◽  
Jeffrey M. Janot ◽  
Len Kravitz ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Exercise Testing ◽  
Ventilatory Threshold ◽  
Maximal Oxygen Consumption ◽  
Oxygen Uptake Kinetics ◽  
Metabolic Responses ◽  
Graded Exercise Testing ◽  
Graded Exercise

Recent examinations have shown lower maximal oxygen consumption during traditional ramp (RAMP) compared with self-paced (SPV) graded exercise testing (GXT) attributed to differences in cardiac output. The current study examined the differences in hemodynamic and metabolic responses between RAMP and SPV during treadmill exercise. Sixteen recreationally trained men (aged23.7 ± 3.0 years) completed 2 separate treadmill GXT protocols. SPV consisted of five 2-min stages (10 min total) of increasing speed clamped by the Borg RPE6-20 scale. RAMP increased speed by 0.16 km/h every 15 s until volitional exhaustion. All testing was performed at 3% incline. Oxygen consumption was measured via indirect calorimetry; hemodynamic function was measured via thoracic impedance and blood lactate (BLa−) was measured via portable lactate analyzer. Differences between SPV and RAMP protocols were analyzed as group means by using paired-samples t tests (R Core Team 2017). Maximal values for SPV and RAMP were similar (p > 0.05) for oxygen uptake (47.1 ± 3.4 vs. 47.4 ± 3.4 mL·kg−1·min−1), heart rate (198 ± 5 vs. 200 ± 6 beats·min−1), ventilation (158.8 ± 20.7 vs. 159.3 ± 19.0 L·min−1), cardiac output (26.9 ± 5.5 vs. 27.9 ± 4.2 L·min−1), stroke volume (SV) (145.9 ± 29.2 vs. 149.8 ± 25.3 mL·beat−1), arteriovenous oxygen difference (18.5 ± 3.1 vs. 19.7 ± 3.1 mL·dL−1), ventilatory threshold (VT) (78.2 ± 7.2 vs. 79.0% ± 7.6%), and peak BLa− (11.7 ± 2.3 vs. 11.5 ± 2.4 mmol·L−1), respectively. In conclusion, SPV elicits similar maximal hemodynamic responses in comparison to RAMP; however, SV kinetics exhibited unique characteristics based on protocol. These results support SPV as a feasible GXT protocol to identify useful fitness parameters (maximal oxygen uptake, oxygen uptake kinetics, and VT).

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