scholarly journals Age and sex influence the balance between maximal cardiac output and peripheral vascular reserve

2010 ◽  
Vol 108 (3) ◽  
pp. 483-489 ◽  
Author(s):  
Samuel J. Ridout ◽  
Beth A. Parker ◽  
Sandra L. Smithmyer ◽  
Joaquin U. Gonzales ◽  
Kenneth C. Beck ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Knee Extensor ◽  
Peripheral Vascular ◽  
Younger Women ◽  
Vascular Reserve ◽  
Femoral Blood Flow ◽  
Maximal Cardiac Output ◽  
Younger Men ◽  
Femoral Blood ◽  
Age And Sex

We evaluated the influence of age and sex on the relationship between central and peripheral vasodilatory capacity. Healthy men (19 younger, 12 older) and women (17 younger, 17 older) performed treadmill and knee extensor exercise to fatigue on separate days while maximal cardiac output (Q, acetylene uptake) and peak femoral blood flow (FBF, Doppler ultrasound) were measured, respectively. Maximal Q was reduced with age similarly in men (Y: 23.6 ± 2.7 vs. O: 17.4 ± 3.5 l/min; P < 0.05) and women (Y: 17.7 ± 1.9 vs. O: 12.3 ± 1.6 l/min; P < 0.05). Peak FBF was similar between younger (Y) and older (O) men (Y: 2.1 ± 0.5 vs. O: 2.2 ± 0.7 l/min) but was lower in older women compared with younger women (Y: 1.9 ± 0.4 vs. O: 1.4 ± 0.4 l/min; P < 0.05). Maximal Q was positively correlated with peak FBF in men (Y: r = 0.55, O: r = 0.74; P < 0.05) but not in women (Y: r = 0.34, O: r = 0.10). Normalization of cardiac output to appendicular muscle mass and peak FBF to quadriceps mass reduced the correlation between these variables in younger men ( r = 0.30), but the significant association remained in older men ( r = 0.68; P < 0.05), with no change in women. These data suggest that 1) aerobic capacity is associated with peripheral vascular reserve in men but not women, and 2) aging is accompanied by a more pronounced sex difference in this relationship.

Influence of age and gender on cardiac output-V˙o 2 relationships during submaximal cycle ergometry

1998 ◽  
Vol 84 (2) ◽  
pp. 599-605 ◽  
Author(s):  
David N. Proctor ◽  
Kenneth C. Beck ◽  
Peter H. Shen ◽  
Tamara J. Eickhoff ◽  
John R. Halliwill ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Age Groups ◽  
Older Men ◽  
Cycle Ergometry ◽  
Age And Gender ◽  
Younger Women ◽  
Leg Cycle Ergometry ◽  
Younger Men ◽  
And Gender

Proctor, David N., Kenneth C. Beck, Peter H. Shen, Tamara J. Eickhoff, John R. Halliwill, and Michael J. Joyner. Influence of age and gender on cardiac output-V˙o 2 relationships during submaximal cycle ergometry. J. Appl. Physiol. 84(2): 599–605, 1998.—It is presently unclear how gender, aging, and physical activity status interact to determine the magnitude of the rise in cardiac output (Q˙c) during dynamic exercise. To clarify this issue, the present study examined theQ˙c-O2 uptake (V˙o 2) relationship during graded leg cycle ergometry in 30 chronically endurance-trained subjects from four groups ( n = 6–8/group): younger men (20–30 yr), older men (56–72 yr), younger women (24–31 yr), and older women (51–72 yr). Q˙c (acetylene rebreathing), stroke volume (Q˙c/heart rate), and whole bodyV˙o 2 were measured at rest and during submaximal exercise intensities (40, 70, and ∼90% of peakV˙o 2). Baseline resting levels of Q˙c were 0.6–1.2 l/min less in the older groups. However, the slopes of theQ˙c-V˙o 2relationship across submaximal levels of cycling were similar among all four groups (5.4–5.9 l/l). The absolute Q˙c associated with a given V˙o 2(1.0–2.0 l/min) was also similar among groups. Resting and exercise stroke volumes (ml/beat) were lower in women than in men but did not differ among age groups. However, older men and women showed a reduced ability, relative to their younger counterparts, to maintain stroke volume at exercise intensities above 70% of peakV˙o 2. This latter effect was most prominent in the oldest women. These findings suggest that neither age nor gender has a significant impact on theQ˙c-V˙o 2relationships during submaximal cycle ergometry among chronically endurance-trained individuals.

scholarly journals Sex differences in leg vasodilation during graded knee extensor exercise in young adults

2007 ◽  
Vol 103 (5) ◽  
pp. 1583-1591 ◽  
Author(s):  
Beth A. Parker ◽  
Sandra L. Smithmyer ◽  
Justin A. Pelberg ◽  
Aaron D. Mishkin ◽  
Michael D. Herr ◽  
...  
Keyword(s):  
Blood Flow ◽  
Femoral Artery ◽  
Knee Extensor ◽  
Activity Levels ◽  
Vascular Conductance ◽  
Arterial Blood ◽  
Vasodilatory Response ◽  
Femoral Blood Flow ◽  
Femoral Blood ◽  
Response To Exercise

Limb vascular conductance responses to pharmacological and nonexercise vasodilator stimuli are generally augmented in women compared with men. In the present investigation, we tested the hypothesis that exercise-induced vasodilator responses are also greater in women than men. Sixteen women and 15 men (20–30 yr) with similar fitness and activity levels performed graded quadriceps exercise (supine, single-leg knee extensions, 40 contractions/min) to maximal exertion. Active limb hemodynamics (left common femoral artery diameter and volumetric blood flow), heart rate (ECG), and beat-to-beat mean arterial blood pressure (MAP; radial artery tonometry) were measured during each 3-min workload (4.8 and 8 W/stage for women and men, respectively). The hyperemic response to exercise (slope of femoral blood flow vs. workload) was greater ( P < 0.01) in women as was femoral blood flow at workloads >15 W. The leg vasodilatory response to exercise (slope of calculated femoral vascular conductance vs. absolute workload) was also greater in women than in men ( P < 0.01) because of the sex difference in hyperemia and the women's lower MAP (∼10–15 mmHg) at all workloads ( P < 0.05). The femoral artery dilated to a significantly greater extent in the women (∼0.5 mm) than in the men (∼0.1 mm) across all submaximal workloads. At maximal exertion, femoral vascular conductance was lower in the men (men, 18.0 ± 0.6 ml·min−1·mmHg−1; women, 22.6 ± 1.4 ml·min−1·mmHg−1; P < 0.01). Collectively, these findings suggest that the vasodilatory response to dynamic leg exercise is greater in young women vs. men.

Peripheral vasodilatation induced by a vasopressin analogue with selective V2-agonism in dogs

1989 ◽  
Vol 256 (6) ◽  
pp. H1621-H1626 ◽  
Author(s):  
J. F. Liard
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Conscious Dogs ◽  
Hemodynamic Effects ◽  
Femoral Blood Flow ◽  
Peripheral Vasodilatation ◽  
Femoral Blood

The selective V2-agonist 4-valine-8-D-arginine vasopressin (VDAVP) increases cardiac output and heart rate and decreases total peripheral resistance in dogs. The mechanism of these hemodynamic effects was examined in the present studies. When infused into the left coronary artery of six conscious dogs for 1 h, VDAVP (10 ng.kg-1.min-1) increased cardiac output and decreased total peripheral resistance more than when given intravenously in the same animals. Administration of VDAVP into the carotid circulation elicited effects that did not differ significantly from those after intravenous infusion at the same rate in six conscious dogs. After destruction of the central nervous system in five dogs anesthetized with pentobarbital, VDAVP failed to increase cardiac output and heart rate but lowered mean arterial pressure and total peripheral resistance. Finally, infusion of VDAVP into the femoral artery of six anesthetized dogs increased femoral blood flow at rates of 1, 5, and 10 ng.kg-1.min-1, whereas none of these rates increased femoral blood flow when given intravenously. Thus the hemodynamic effects of VDAVP appear to result primarily from a peripheral vasodilatory action, with possible contribution from a positive inotropic effect. We found no evidence that central effects of VDAVP were importantly involved in its cardiovascular action.

scholarly journals Cardiovascular responses to dynamic exercise with acute anemia in humans

1997 ◽  
Vol 273 (4) ◽  
pp. H1787-H1793 ◽  
Author(s):  
Maria D. Koskolou ◽  
Robert C. Roach ◽  
José A. L. Calbet ◽  
Göran Rådegran ◽  
Bengt Saltin
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Hemoglobin Concentration ◽  
Cardiovascular Responses ◽  
Submaximal Exercise ◽  
Peak Exercise ◽  
Limb Blood Flow ◽  
Maximal Cardiac Output

We hypothesized that reducing arterial O2 content ([Formula: see text]) by lowering the hemoglobin concentration ([Hb]) would result in a higher blood flow, as observed with a low [Formula: see text], and maintenance of O2 delivery. Seven young healthy men were studied twice, at rest and during two-legged submaximal and peak dynamic knee extensor exercise in a control condition (mean control [Hb] 144 g/l) and after 1–1.5 liters of whole blood had been withdrawn and replaced with albumin {mean drop in [Hb] 29 g/l (range 19–38 g/l); low [Hb]}. Limb blood flow (LBF) was higher ( P < 0.01) with low [Hb] during submaximal exercise (i.e., at 30 W, LBF was 2.5 ± 0.1 and 3.0 ± 0.1 l/min for control [Hb] and low [Hb], respectively; P < 0.01), resulting in a maintained O2 delivery and O2 uptake for a given workload. However, at peak exercise, LBF was unaltered (6.5 ± 0.4 and 6.6 ± 0.6 l/min for control [Hb] and low [Hb], respectively), which resulted in an 18% reduction in O2 delivery ( P < 0.01). This occurred despite peak cardiac output in neither condition reaching >75% of maximal cardiac output (∼26 l/min). It is concluded that a low CaO2 induces an elevation in submaximal muscle blood flow and that O2 delivery to contracting muscles is tightly regulated.

scholarly journals Resistance training increases basal limb blood flow and vascular conductance in aging humans

2006 ◽  
Vol 101 (5) ◽  
pp. 1351-1355 ◽  
Author(s):  
Maria M. Anton ◽  
Miriam Y. Cortez-Cooper ◽  
Allison E. DeVan ◽  
Daria B. Neidre ◽  
Jill N. Cook ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cardiac Output ◽  
Strength Training ◽  
Whole Body ◽  
Control Group ◽  
Limb Blood Flow ◽  
Vascular Conductance ◽  
Femoral Blood Flow ◽  
Femoral Blood

Age-related reductions in basal limb blood flow and vascular conductance are associated with the metabolic syndrome, functional impairments, and osteoporosis. We tested the hypothesis that a strength training program would increase basal femoral blood flow in aging adults. Twenty-six sedentary but healthy middle-aged and older subjects were randomly assigned to either a whole body strength training intervention group (52 ± 2 yr, 3 men, 10 women) who underwent three supervised resistance training sessions per week for 13 wk or a control group (53 ± 2 yr, 4 men, 9 women) who participated in a supervised stretching program. At baseline, there were no significant differences in blood pressure, cardiac output, basal femoral blood flow (via Doppler ultrasound), vascular conductance, and vascular resistance between the two groups. The strength training group increased maximal strength in all the major muscle groups tested ( P < 0.05). Whole body lean body mass increased ( P < 0.05) with strength training, but leg fat-free mass did not. Basal femoral blood flow and vascular conductance increased by 55–60% after strength training (both P < 0.05). No such changes were observed in the control group. In both groups, there were no significant changes in brachial blood pressure, plasma endothelin-1 and angiotensin II concentrations, femoral artery wall thickness, cardiac output, and systemic vascular resistance. Our results indicate that short-term strength training increases basal femoral blood flow and vascular conductance in healthy middle-aged and older adults.

Audiences' Perceptions of Sources' Credibility in a Television Interview Setting

1996 ◽  
Vol 83 (2) ◽  
pp. 579-588 ◽  
Author(s):  
Erika Engstrom
Keyword(s):  
Older Women ◽  
Semantic Differential ◽  
Male And Female ◽  
Younger Women ◽  
Clothing Style ◽  
Younger Men ◽  
Television Interview ◽  
Age And Sex ◽  
Interview Setting

This experiment examined the differences between older and younger men and women's evaluations of differently dressed sources' credibility. 165 subjects viewed simulated interviews for television in which male and female sources dressed either conservatively or casually. Subjects then rated them according to semantic-differential scales which measured targets' competence, character, and dynamism. Subjects were categorized by age and sex. Over-all, younger women (those between the ages of 18 and 34 years) gave high ratings of competence, character, and dynamism to all sources regardless of clothing style, while older women (those 35 years and older) gave the lowest ratings. This was especially noted for their evaluations of female sources. Men, regardless of age rated all sources similarly.

Regional blood flow and vascular resistance during hypothermia in dog

1961 ◽  
Vol 201 (3) ◽  
pp. 485-491 ◽  
Author(s):  
Bjorn Westin ◽  
N. Sehgal ◽  
N. S. Assali
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Sine Wave ◽  
Blood Flows ◽  
Femoral Blood Flow ◽  
Regional Vascular Resistance ◽  
Femoral Blood ◽  
Carotid Flow

Changes in regional blood flow and regional vascular resistance during hypothermia in dogs with intact or abolished shivering mechanisms were measured with sine-wave electromagnetic flowmeters. In animals with shivering intact, cooling produced a fall in renal and carotid blood flows, despite a rise or no change in cardiac output. The fall was caused by an increase in renal and carotid vascular resistances. Femoral blood flow increased because of a decrease in vascular resistance. In animals with shivering abolished, cooling evoked a fall in the cardiac output and in renal and femoral blood flows, due to an increase in the vascular resistance. Upon rewarming, femoral flow immediately rose to values far above control. Carotid flow increased during cooling because of a decline in carotid resistance. Such a decline might have been related to the elevated blood Pco2 observed in the nonshivering animals.

Circulatory effects of moderately and severely increased intracranial pressure in the dog

1972 ◽  
Vol 36 (6) ◽  
pp. 721-727 ◽  
Author(s):  
Norberto C. Gonzalez ◽  
John Overman ◽  
John A. Maxwell
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Cardiac Output ◽  
Intracranial Pressure ◽  
Arterial Blood Pressure ◽  
Peripheral Resistance ◽  
Arterial Blood ◽  
Femoral Blood Flow ◽  
Femoral Blood

✓ Anesthetized dogs were subjected to elevated intracranial pressure (ICP) of 60 and 100 mm Hg. At 60 mm Hg, decreases in heart rate and arterial blood pressure were observed associated with an increase in femoral blood flow that suggested vasodilation in the somatic areas. Cardiac output showed little change. Subsequent elevation of ICP to 100 mm Hg was followed by an increase in arterial blood pressure; cardiac output increased, and femoral flow increased still further. Since resistance to flow did not change, the hypertension was thought to be due to an increase in flow rather than peripheral resistance. An increase in heart rate was associated with the elevation in cardiac output; the fact that femoral blood flow increased proportionately more than cardiac output suggested a redistribution of blood flow. The changes in peripheral blood flow and in cardiac output were associated with a decrease in the arteriovenous oxygen (A–VO2) difference. No signs of tissue hypoxia were observed; specifically there was no significant change in the lactate-to-pyruvate ratio; the changes in A–VO2 difference were correlated with changes in flow and the product of the two variables, namely, oxygen consumption, remained unchanged. The data show that experimental elevation of ICP restricted to moderate levels is followed by hemodynamic changes suggesting peripheral vasodilation, and that when an increase in blood pressure then occurs, it is due to an increase in blood flow despite the decrease in peripheral resistance.

scholarly journals Human muscle length-dependent changes in blood flow

2012 ◽  
Vol 112 (4) ◽  
pp. 560-565 ◽  
Author(s):  
John McDaniel ◽  
Stephen J. Ives ◽  
Russell S. Richardson
Keyword(s):  
Blood Flow ◽  
Knee Joint ◽  
Joint Angle ◽  
Muscle Blood Flow ◽  
Muscle Length ◽  
Limb Blood Flow ◽  
Knee Joint Angle ◽  
Femoral Blood Flow ◽  
Femoral Blood ◽  
Cyclic Changes

Although a multitude of factors that influence skeletal muscle blood flow have been extensively investigated, the influence of muscle length on limb blood flow has received little attention. Thus the purpose of this investigation was to determine if cyclic changes in muscle length influence resting blood flow. Nine healthy men (28 ± 4 yr of age) underwent a passive knee extension protocol during which the subjects' knee joint was passively extended and flexed through 100–180° knee joint angle at a rate of 1 cycle per 30 s. Femoral blood flow, cardiac output (CO), heart rate (HR), stroke volume (SV), and mean arterial pressure (MAP) were continuously recorded during the entire protocol. These measurements revealed that slow passive changes in knee joint angle did not have a significant influence on HR, SV, MAP, or CO; however, net femoral blood flow demonstrated a curvilinear increase with knee joint angle ( r2 = 0.98) such that blood flow increased by ∼90% (125 ml/min) across the 80° range of motion. This net change in blood flow was due to a constant antegrade blood flow across knee joint angle and negative relationship between retrograde blood flow and knee joint angle ( r2 = 0.98). Thus, despite the absence of central hemodynamic changes and local metabolic factors, blood flow to the leg was altered by changes in muscle length. Therefore, when designing research protocols, researchers need to be cognizant of the fact that joint angle, and ultimately muscle length, influence limb blood flow.

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