Effects of epinephrine on cardiovascular and metabolic responses to leg exercise in man

1963 ◽  
Vol 18 (6) ◽  
pp. 1118-1122 ◽  
Author(s):  
Robert J. Marshall ◽  
John T. Shepherd
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Oxygen Content ◽  
Muscle Blood Flow ◽  
Venous Blood ◽  
Metabolic Responses ◽  
Leg Muscles ◽  
Leg Exercise ◽  
The Subject ◽  
The Mean

In studies on six experienced subjects lying supine, cardiac output and oxygen content of femoral venous blood were measured with the subject at rest, during the increase in muscle blood flow caused by intravenous infusion of epinephrine, during mild leg exercise, and during identical exercise combined with an infusion. The oxygen content of the blood from the exercising limb was much higher (average, 50%) during an infusion than when no infusion was given (average, 32%). The mean increase in cardiac output during the combined maneuver (8.2 liters/min) almost equaled the sum of the increases during the separate infusion (3.7 liters) and during exercise (4.7 liters). All individual studies showed approximately this same result. Thus, the additional blood supplied to the leg muscles by the infusion did not appear to be used for metabolic purposes during exercise. cardiac output; muscle blood flow Submitted on March 22, 1963

Regional distribution of blood flow during mild dynamic leg exercise in the baboon

1983 ◽  
Vol 55 (4) ◽  
pp. 1173-1177 ◽  
Author(s):  
A. R. Hohimer ◽  
J. R. Hales ◽  
L. B. Rowell ◽  
O. A. Smith
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cardiac Output ◽  
Muscle Blood Flow ◽  
Regional Distribution ◽  
Tissue Blood Flow ◽  
Blood Flows ◽  
Visceral Organs ◽  
Arterial Blood ◽  
Leg Exercise

Five chair-restrained baboons were trained with operant techniques and a food reward to perform dynamic leg exercise. Cardiac output and blood flows to most tissues were determined by radioactive microsphere distribution. After 2 min of exercise mean arterial blood pressure had increased by 11 +/- 3% (SE), heart rate by 34 +/- 7%, cardiac output by 50 +/- 12%, and O2 consumption by 157 +/- 17%. The blood flow to exercising leg muscle increased by 585 +/- 338% and to the myocardium by 35 +/- 19%. Blood flow to torso and limb skin fell by 38 +/- 4 and 38 +/- 6%, respectively, and similar reductions occurred in adipose tissue blood flow. Nonworking skeletal muscle blood flow decreased by 30 +/- 10%. Renal blood flow was lowered by 16 +/-2%. The lower visceral organs had more variable responses, but when grouped together total splanchnic blood flow fell by 21 +/- 9%. Blood flow to the brain was unchanged with exercise, whereas spinal cord perfusion increased 23 +/- 3%. Thus during short dynamic exercise baboons redistributed blood flow away from skin, fat, nonworking muscles, and visceral organs to supply the needs of exercising muscles. Our data suggest the baboon is a useful animal model for investigating vascular responses of tissues, such as torso skin, adipose, individual visceral organs, and the spinal cord, that cannot be examined in humans.

Human respiratory muscle blood flow measured by near-infrared spectroscopy and indocyanine green

2008 ◽  
Vol 104 (4) ◽  
pp. 1202-1210 ◽  
Author(s):  
Jordan A. Guenette ◽  
Ioannis Vogiatzis ◽  
Spyros Zakynthinos ◽  
Dimitrios Athanasopoulos ◽  
Maria Koskolou ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Infrared Spectroscopy ◽  
Respiratory Muscle ◽  
Near Infrared ◽  
Vastus Lateralis ◽  
Muscle Blood Flow ◽  
Work Of Breathing ◽  
Dilution Method ◽  
Transdiaphragmatic Pressure

Measurement of respiratory muscle blood flow (RMBF) in humans has important implications for understanding patterns of blood flow distribution during exercise in healthy individuals and those with chronic disease. Previous studies examining RMBF in humans have required invasive methods on anesthetized subjects. To assess RMBF in awake subjects, we applied an indicator-dilution method using near-infrared spectroscopy (NIRS) and the light-absorbing tracer indocyanine green dye (ICG). NIRS optodes were placed on the left seventh intercostal space at the apposition of the costal diaphragm and on an inactive control muscle (vastus lateralis). The primary respiratory muscles within view of the NIRS optodes include the internal and external intercostals. Intravenous bolus injection of ICG allowed for cardiac output (by the conventional dye-dilution method with arterial sampling), RMBF, and vastus lateralis blood flow to be quantified simultaneously. Esophageal and gastric pressures were also measured to calculate the work of breathing and transdiaphragmatic pressure. Measurements were obtained in five conscious humans during both resting breathing and three separate 5-min bouts of constant isocapnic hyperpnea at 27.1 ± 3.2, 56.0 ± 6.1, and 75.9 ± 5.7% of maximum minute ventilation as determined on a previous maximal exercise test. RMBF progressively increased (9.9 ± 0.6, 14.8 ± 2.7, 29.9 ± 5.8, and 50.1 ± 12.5 ml·100 ml−1·min−1, respectively) with increasing levels of ventilation while blood flow to the inactive control muscle remained constant (10.4 ± 1.4, 8.7 ± 0.7, 12.9 ± 1.7, and 12.2 ± 1.8 ml·100 ml−1·min−1, respectively). As ventilation rose, RMBF was closely and significantly correlated with 1) cardiac output ( r = 0.994, P = 0.006), 2) the work of breathing ( r = 0.995, P = 0.005), and 3) transdiaphragmatic pressure ( r = 0.998, P = 0.002). These data suggest that the NIRS-ICG technique provides a feasible and sensitive index of RMBF at different levels of ventilation in humans.

Effect of two methods of hand heating on body temperature, forearm blood flow, and deep venous oxygen saturation

1990 ◽  
Vol 259 (5) ◽  
pp. E639-E643 ◽  
Author(s):  
I. W. Gallen ◽  
I. A. Macdonald
Keyword(s):  
Blood Flow ◽  
Body Temperature ◽  
Oxygen Content ◽  
Forearm Blood Flow ◽  
Venous Blood ◽  
Blood Oxygen ◽  
Left Hand ◽  
Venous Oxygen Saturation ◽  
Baseline Values ◽  
Healthy Females

Two methods of hand heating [warmed blanket 40 degrees C (WB) and warm-air box 55 degrees C (WA)] were compared with the effect of no heating (control) in six healthy females. After 30 min baseline, the left hand was either heated for 1 h or not heated. Measurements were made of skin temperature (ST), core temperature (CT), right forearm (FBF) and skin blood flow (SBF), and right forearm deep venous blood oxygen content with and without occlusion of the hand circulation. CT rose above baseline in WB (by +0.2 degrees C, P less than 0.01) but not with control or WA. Abdominal ST rose only with WB (by +0.66 degrees C above baseline, P less than 0.01). FBF increased above baseline values with both WA (by +10 ml.l forearm-1.min-1) and WB (by +12 ml.l forearm-1.min-1), but neither was significantly greater than the control. SBF increased above baseline only with WB (by +202 mV, P less than 0.01), and this was significantly greater than control SBF. With an occluded hand circulation, deep venous oxygen content rose above baseline values with WB only (+6.0%, P less than 0.01) but was not greater than control with either method of hand heating. We conclude that using a warm-air box has less effect than a heated blanket on the measured variables.

Costal vs. crural diaphragmatic blood flow during submaximal and near-maximal exercise in ponies

1988 ◽  
Vol 65 (4) ◽  
pp. 1514-1519 ◽  
Author(s):  
M. Manohar
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Left Atrium ◽  
Maximal Exercise ◽  
Muscle Blood Flow ◽  
Intercostal Muscle ◽  
Quiet Breathing ◽  
Blood Flows ◽  
Graded Exercise ◽  
Crural Diaphragm

The present study was carried out 1) to compare blood flow in the costal and crural regions of the equine diaphragm during quiet breathing at rest and during graded exercise and 2) to determine the fraction of cardiac output needed to perfuse the diaphragm during near-maximal exercise. By the use of radionuclide-labeled 15-micron-diam microspheres injected into the left atrium, diaphragmatic and intercostal muscle blood flow was studied in 10 healthy ponies at rest and during three levels of exercise (moderate: 12 mph, heavy: 15 mph, and near-maximal: 19-20 mph) performed on a treadmill. At rest, in eucapnic ponies, costal (13 +/- 3 ml.min-1.100 g-1) and crural (13 +/- 2 ml.min-1.100 g-1) phrenic blood flows were similar, but the costal diaphragm received a much larger percentage of cardiac output (0.51 +/- 0.12% vs. 0.15 +/- 0.03% for crural diaphragm). Intercostal muscle perfusion at rest was significantly less than in either phrenic region. Graded exercise resulted in significant progressive increments in perfusion to these tissues. Although during exercise, crural diaphragmatic blood flow was not different from intercostal muscle blood flow, these values remained significantly less (P less than 0.01) than in the costal diaphragm. At moderate, heavy, and near-maximal exercise, costal diaphragmatic blood flow (123 +/- 12, 190 +/- 12, and 245 +/- 18 ml.min-1.100 g-1) was 143%, 162%, and 162%, respectively, of that for the crural diaphragm (86 +/- 10, 117 +/- 8, and 151 +/- 14 ml.min-1.100 g-1).(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Reduced submaximal leg blood flow after high-intensity aerobic training

2001 ◽  
Vol 91 (6) ◽  
pp. 2619-2627 ◽  
Author(s):  
David N. Proctor ◽  
Jordan D. Miller ◽  
Niki M. Dietz ◽  
Christopher T. Minson ◽  
Michael J. Joyner
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Power Output ◽  
High Intensity ◽  
Aerobic Training ◽  
Muscle Blood Flow ◽  
Splanchnic Blood Flow ◽  
Active Muscle ◽  
Leg Blood Flow ◽  
Power Outputs

This study evaluated the hypothesis that active muscle blood flow is lower during exercise at a given submaximal power output after aerobic conditioning as a result of unchanged cardiac output and blunted splanchnic vasoconstriction. Eight untrained subjects (4 men, 4 women, 23–31 yr) performed high-intensity aerobic training for 9–12 wk. Leg blood flow (femoral vein thermodilution), splanchnic blood flow (indocyanine green clearance), cardiac output (acetylene rebreathing), whole body O2 uptake (V˙o 2), and arterial-venous blood gases were measured before and after training at identical submaximal power outputs (70 and 140 W; upright 2-leg cycling). Training increased ( P < 0.05) peak V˙o 2(12–36%) but did not significantly change submaximalV˙o 2 or cardiac output. Leg blood flow during both submaximal power outputs averaged 18% lower after training ( P = 0.001; n = 7), but these reductions were not correlated with changes in splanchnic vasoconstriction. Submaximal leg V˙o 2 was also lower after training. These findings support the hypothesis that aerobic training reduces active muscle blood flow at a given submaximal power output. However, changes in leg and splanchnic blood flow resulting from high-intensity training may not be causally linked.

Dependence of muscleV˙o 2on blood flow dynamics at onset of forearm exercise

1996 ◽  
Vol 81 (4) ◽  
pp. 1619-1626 ◽  
Author(s):  
R. L. Hughson ◽  
J. K. Shoemaker ◽  
M. E. Tschakovsky ◽  
J. M. Kowalchuk
Keyword(s):  
Blood Flow ◽  
Muscle Blood Flow ◽  
Venous Blood ◽  
Lactate Concentration ◽  
Flow Dynamics ◽  
Cross Sectional ◽  
Mean Response Time ◽  
Rate Of Increase ◽  
Blood Flow Dynamics ◽  
Forearm Exercise

Hughson, R. L., J. K. Shoemaker, M. E. Tschakovsky, and J. M. Kowalchuk. Dependence muscle ofV˙o 2on blood flow dynamics at the onset of forearm exercise. J. Appl. Physiol. 81(4): 1619–1626, 1996.—The hypothesis that the rate of increase in muscle O2 uptake (V˙o 2 mus) at the onset of exercise is influenced by muscle blood flow was tested during forearm exercise with the arm either above or below heart level to modify perfusion pressure. Ten young men exercised at a power of ∼2.2 W, and five of these subjects also worked at 1.4 W. Blood flow to the forearm was calculated from the product of blood velocity and cross-sectional area obtained with Doppler techniques. Venous blood was sampled from a deep forearm vein to determine O2 extraction. The rate of increase inV˙o 2 musand blood flow was assessed from the mean response time (MRT), which is the time to achieve ∼63% increase from baseline to steady state. In the arm below heart position during the 2.2-W exercise, blood flow andV˙o 2 musboth increased, with a MRT of ∼30 s. With the arm above the heart at this power, the MRTs for blood flow [79.8 ± 15.7 (SE) s] and V˙o 2 mus(50.2 ± 4.0 s) were both significantly slower. Consistent with these findings were the greater increases in venous plasma lactate concentration over resting values in the above heart position (2.8 ± 0.4 mmol/l) than in the below heart position (0.9 ± 0.2 mmol/l). At the lower power, both blood flow andV˙o 2 musalso increased more rapidly with the arm below compared with above the heart. These data support the hypothesis that changes in blood flow at the onset of exercise have a direct effect on oxidative metabolism through alterations in O2transport.

Cardiovascular adjustments to laboratory diving in beavers and nutria

1982 ◽  
Vol 242 (5) ◽  
pp. R434-R440
Author(s):  
T. McKean
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Regional Blood Flow ◽  
Castor Canadensis ◽  
Venous Blood ◽  
Regional Distribution ◽  
Blood Gases ◽  
Myocastor Coypus ◽  
Recovery From Anesthesia ◽  
Rate Of Decline

Beavers (Castor canadensis) and nutria (Myocastor coypus) were anesthetized with halothane and catheters placed in the left ventricle, aorta and pulmonary artery, right ventricle or right atrium. The animals were strapped to a board and following recovery from anesthesia the following measurements were taken: regional distribution of blood flow, cardiac output, O2 consumption, arterial and venous blood gases, and pH. The animal was then immersed in 15-20 degrees C water for up to 2.75 min (nutria) or 4 min (beaver) and the measurements repeated. Heart rate and cardiac output decreased by 80 and 75%, respectively. Arterial and venous oxygen partial pressure and content fell as did pH whereas CO2 pressures rose during diving. Oxygen consumption at rest was 124 and 102% of that predicted on the basis of body mass for the beaver and nutria, respectively. Rate of decline of O2 stores during diving decreased by 93% in beavers and 89% in nutria compared to the predive value. Regional blood flow decreased to all organs except the adrenals, heart, and lungs. Blood flow to the brain increased during diving.

Circulation of sympathectomized dogs under pentobarbital anesthesia

1965 ◽  
Vol 208 (4) ◽  
pp. 790-794
Author(s):  
Shu Chien ◽  
Shunichi Usami
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Blood Volume ◽  
Total Blood Volume ◽  
Central Blood Volume ◽  
Total Blood ◽  
Pentobarbital Anesthesia ◽  
Blood Flows ◽  
The Mean ◽  
Mean Circulation

In sympathectomized-splenectomized dogs under pentobarbital anesthesia, the total blood volume averaged 78 ml/kg, with 20% in the splanchnic circulation and 28% in the central blood volume. These values are almost the same as those found in the splenectomized (control) dogs with the sympathetic system intact. The over-all and the splanchnic Fcells factors are also not significantly different between these two groups. The sympathectomized animals had lower arterial pressure, cardiac output, and splanchnic blood flow, but the resistances calculated for the total and the splanchnic circulations were not significantly different from those of the control dogs. The mean circulation times for the total, the central, and the splanchnic circulations were all longer in the sympathectomized dogs. The data indicate that, under pentobarbital anesthesia, sympathectomized dogs are characterized by slower blood flows without any significant changes in either the blood volume or vascular resistance.

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