Differential effects of aging on limb blood flow in humans

2006 ◽  
Vol 290 (1) ◽  
pp. H272-H278 ◽  
Author(s):  
Anthony J. Donato ◽  
Abhimanyu Uberoi ◽  
D. Walter Wray ◽  
Steven Nishiyama ◽  
Lesley Lawrenson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Mass ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Vascular Conductance ◽  
Leg Blood Flow ◽  
Arterial Blood ◽  
Relative Exercise Intensity ◽  
Effects Of Aging ◽  
Forearm Muscle

Aging appears to attenuate leg blood flow during exercise; in contrast, such data are scant and do not support this contention in the arm. Therefore, to determine whether aging has differing effects on blood flow in the arm and leg, eight young (22 ± 6 yr) and six old (71 ± 15 yr) subjects separately performed dynamic knee extensor [0, 3, 6, 9 W; 20, 40, 60% maximal work rate (WRmax)] and handgrip exercise (3, 6, 9 kg at 0.5 Hz; 20, 40, 60% WRmax). Arterial diameter, blood velocity (Doppler ultrasound), and arterial blood pressure (radial tonometry) were measured simultaneously at each of the submaximal workloads. Quadriceps muscle mass was smaller in the old (1.6 ± 0.1 kg) than the young (2.1 ± 0.2 kg). When normalized for this difference in muscle mass, resting seated blood flow was similar in young and old subjects (young, 115 ± 28; old, 114 ± 39 ml·kg−1·min−1). During exercise, blood flow and vascular conductance were attenuated in the old whether expressed in absolute terms for a given absolute workload or more appropriately expressed as blood flow per unit muscle mass at a given relative exercise intensity (young, 1,523 ± 329; old, 1,340 ± 157 ml·kg−1·min−1 at 40% WRmax). In contrast, aging did not affect forearm muscle mass or attenuate rest or exercise blood flow or vascular conductance in the arm. In conclusion, aging induces limb-specific alterations in exercise blood flow regulation. These alterations result in reductions in leg blood flow during exercise but do not impact forearm blood flow.

Sex-specific influence of aging on exercising leg blood flow

2008 ◽  
Vol 104 (3) ◽  
pp. 655-664 ◽  
Author(s):  
Beth A. Parker ◽  
Sandra L. Smithmyer ◽  
Justin A. Pelberg ◽  
Aaron D. Mishkin ◽  
David N. Proctor
Keyword(s):  
Blood Flow ◽  
Older Women ◽  
Muscle Mass ◽  
Quadriceps Muscle ◽  
Work Rate ◽  
Healthy Human ◽  
Leg Blood Flow ◽  
Arterial Blood ◽  
Rate Interaction ◽  
Effects Of Aging

Our previous work suggests that healthy human aging is associated with sex-specific differences in leg vascular responses during large muscle mass exercise (2-legged cycling) (Proctor DN, Parker BA. Microcirculation 13: 315–327, 2006). The present study determined whether age × sex interactions in exercising leg hemodynamics persist during small muscle mass exercise that is not limited by cardiac output. Thirty-one young (20–30 yr; 15 men/16 women) and 31 older (60–79 yr; 13 men/18 women) healthy, normally active adults performed graded single-leg knee extensions to maximal exertion. Femoral artery blood velocity and diameter (Doppler ultrasound), heart rate (ECG), and beat-to-beat arterial blood pressure (mean arterial pressure, radial artery tonometry) were measured during each 3-min work rate (4.8 and 8 W/stage for women and men, respectively). The results (means ± SE) were as follows. Despite reduced resting leg blood flow and vascular conductance, older men exhibited relatively preserved exercising leg hemodynamic responses. Older women, by contrast, exhibited attenuated hyperemic (young: 52 ± 3 ml·min−1·W−1; vs. older: 40 ± 4 ml·min−1·W−1; P = 0.02) and vasodilatory responses (young: 0.56 ± 0.06 ml·min−1·mmHg−1·W−1 vs. older: 0.37 ± 0.04 ml·min−1·mmHg−1 W−1; P < 0.01) to exercise compared with young women. Relative (percentage of maximal) work rate comparisons of all groups combined also revealed attenuated vasodilator responses in older women ( P < 0.01 for age × sex × work rate interaction). These sex-specific age differences were not abolished by consideration of hemoglobin, quadriceps muscle, muscle recruitment, and mechanical influences on muscle perfusion. Collectively, these findings suggest that local factors contribute to the sex-specific effects of aging on exercising leg hemodynamics in healthy adults.

scholarly journals The role of muscle mass in exercise-induced hyperemia

2014 ◽  
Vol 116 (9) ◽  
pp. 1204-1209 ◽  
Author(s):  
Ryan S. Garten ◽  
H. Jonathan Groot ◽  
Matthew J. Rossman ◽  
Jayson R. Gifford ◽  
Russell S. Richardson
Keyword(s):  
Blood Flow ◽  
Muscle Mass ◽  
Coefficient Of Variation ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Thigh Muscle ◽  
Relative Exercise Intensity ◽  
Exercise Muscle ◽  
Exercise Induced ◽  
The Impact

Exercise-induced hyperemia is often normalized for muscle mass, and this value is sometimes evaluated at relative exercise intensities to take muscle recruitment into account. Therefore, this study sought to better understand the impact of muscle mass on leg blood flow (LBF) during exercise. LBF was assessed by Doppler ultrasound in 27 young healthy male subjects performing knee-extensor (KE) exercise at three absolute (5, 15, and 25 W) and three relative [20, 40, and 60% of maximum KE (KEmax)] workloads. Thigh muscle mass (5.2–8.1 kg) and LBF were significantly correlated at rest ( r = 0.54; P = 0.004). Exercise-induced hyperemia was linearly related to absolute workload, but revealed substantial between-subject variability, documented by the coefficient of variation (5 W: 17%; 15 W: 16%; 25 W: 16%). Quadriceps muscle mass (1.5–2.7 kg) and LBF were not correlated at 5, 15, or 25 W ( r = 0.09–0.01; P = 0.7–0.9). Normalizing blood flow for quadriceps muscle mass did not improve the coefficient of variation at each absolute workload (5 W: 21%; 15 W: 21%; 25 W: 22%), while the additional evaluation at relative exercise intensities resulted in even greater variance (20% KEmax: 29%; 40% KEmax: 29%; 60% KEmax: 27%). Similar findings were documented when subjects were parsed into high and low aerobic capacity. Thus, in contrast to rest, blood flow during exercise is unrelated to muscle mass, and simply normalizing for muscle mass or comparing normalized blood flow at a given relative exercise intensity has no effect on the inherent blood flow variability. Therefore, during exercise, muscle mass does not appear to be a determinant of the hyperemic response.

Lack of age-related decreases in basal whole leg blood flow in resistance-trained men

2005 ◽  
Vol 99 (4) ◽  
pp. 1384-1390 ◽  
Author(s):  
Motohiko Miyachi ◽  
Hirofumi Tanaka ◽  
Hiroshi Kawano ◽  
Mayumi Okajima ◽  
Izumi Tabata
Keyword(s):  
Blood Flow ◽  
Muscle Mass ◽  
Young Men ◽  
Middle Aged ◽  
Vascular Conductance ◽  
Leg Blood Flow ◽  
Age Related ◽  
Blood Pressures ◽  
Leg Muscle ◽  
Activity Groups

Reductions in basal leg blood flow have been implicated in the pathogenesis of metabolic syndrome and functional impairment in humans. We tested the hypothesis that reductions in basal whole leg blood flow with age are either absent or attenuated in those who perform regular strength training. A total of 104 normotensive men aged 20–34 yr (young) and 35–65 yr (middle aged), who were either sedentary or resistance trained, were studied. Mean and diastolic blood pressures were higher ( P < 0.05–0.001) in the middle-aged compared with the young men, but there were no significant differences between the sedentary and resistance-trained groups. In the sedentary group, basal whole leg blood flow (duplex Doppler ultrasound) and vascular conductance were lower (∼30 and ∼38%, respectively; P < 0.01) in the middle-aged compared with the young men. There were no such age-related differences in the resistance-trained group. In the young men, basal whole leg blood flow and vascular conductance were not different between the two activity groups, but, in the middle-aged men, they were higher (∼35 and ∼36%, respectively; P < 0.01) in the resistance-trained men than in the sedentary men. When blood flow and vascular conductance were expressed relative to the leg muscle mass, the results were essentially the same. We concluded that the age-related reduction in basal whole leg blood flow is absent in resistance-trained men. These results suggest that resistance training may favorably influence leg perfusion in aging humans, independent of its impact on leg muscle mass.

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.

Influence of skin temperature on central thermoregulatory control of leg blood flow

1981 ◽  
Vol 50 (5) ◽  
pp. 974-978 ◽  
Author(s):  
D. W. Proppe
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Skin Temperature ◽  
Major Influence ◽  
Papio Anubis ◽  
Vascular Conductance ◽  
Leg Blood Flow ◽  
Blood Temperature ◽  
Arterial Blood ◽  
Arterial Blood Temperature

This study examined the influence of elevated skin temperature (Tsk) on the central thermoregulatory control of leg blood flow in five unanesthetized, chronically instrumented, resting baboons (Papio anubis and P. cynocephalus). In each experiment, mean iliac blood flow (MIBF), mean arterial blood pressure, arterial blood temperature (Tbl), and Tsk were measured, and iliac vascular conductance (IVC) was calculated. A heat exchanger was incorporated into a chronic arteriovenous femoral shunt to control Tbl. The protocol consisted of raising Tbl approximately 2.6 degrees C in thermoneutral environment (cool Tsk) an then again after Tsk had been elevated by environmental heating. A major influence of raising Tsk was the lowering of threshold Tbl at which the rise in MIBF and IVC commenced. This threshold Tbl was lowered at least 0.8 degrees C on the average. Also, over the whole range of Tbl studied (37.0-39.6 degrees C), MIBF and IVC were higher at high Tsk than at cool Tsk. Thus an elevation of Tsk significantly influences the control of skin blood flow by central thermoreceptors.

scholarly journals Taming the “sleeping giant”: the role of endothelin-1 in the regulation of skeletal muscle blood flow and arterial blood pressure during exercise

2013 ◽  
Vol 304 (1) ◽  
pp. H162-H169 ◽  
Author(s):  
Zachary Barrett-O'Keefe ◽  
Stephen J. Ives ◽  
Joel D. Trinity ◽  
Garrett Morgan ◽  
Matthew J. Rossman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiovascular Response ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Leg Blood Flow ◽  
Arterial Blood ◽  
Before And After ◽  
Exercise Induced ◽  
Response To Exercise

The cardiovascular response to exercise is governed by a combination of vasodilating and vasoconstricting influences that optimize exercising muscle perfusion while protecting mean arterial pressure (MAP). The degree to which endogenous endothelin (ET)-1, the body's most potent vasoconstrictor, participates in this response is unknown. Thus, in eight young (24 ± 2 yr), healthy volunteers, we examined leg blood flow, MAP, tissue oxygenation, heart rate, leg arterial-venous O2 difference, leg O2 consumption, pH, and net ET-1 and lactate release at rest and during knee extensor exercise (0, 5, 10, 15, 20, and 30 W) before and after an intra-arterial infusion of BQ-123 [ET subtype A (ETA) receptor antagonist]. At rest, BQ-123 did not evoke a change in leg blood flow or MAP. During exercise, net ET-1 release across the exercising leg increased approximately threefold. BQ-123 increased leg blood flow by ∼20% across all work rates (changes of 113 ± 76, 176 ± 83, 304 ± 108, 364 ± 130, 502 ± 117, and 570 ± 178 ml/min at 0, 5, 10, 15, 20, and 30 W, respectively) and attenuated the exercise-induced increase in MAP by ∼6%. The increase in leg blood flow was accompanied by a ∼9% increase in leg O2 consumption with an unchanged arterial-venous O2 difference and deoxyhemoglobin, suggesting a decline in intramuscular efficiency after ETA receptor blockade. Together, these findings identify a significant role of the ET-1 pathway in the cardiovascular response to exercise, implicating vasoconstriction via the ETA receptor as an important mechanism for both the restraint of blood flow in the exercising limb and maintenance of MAP in healthy, young adults.

Aging attenuates vascular and metabolic plasticity but does not limit improvement in muscle Vo2 max

2004 ◽  
Vol 286 (4) ◽  
pp. H1565-H1572 ◽  
Author(s):  
L. Lawrenson ◽  
J. Hoff ◽  
R. S. Richardson
Keyword(s):  
Blood Flow ◽  
Exercise Training ◽  
Muscle Mass ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Whole Body ◽  
Metabolic Adaptation ◽  
Metabolic Plasticity ◽  
Small Muscle

The interactions between exercise, vascular and metabolic plasticity, and aging have provided insight into the prevention and restoration of declining whole body and small muscle mass exercise performance known to occur with age. Metabolic and vascular adaptations to normoxic knee-extensor exercise training (1 h 3 times a week for 8 wk) were compared between six sedentary young (20 ± 1 yr) and six sedentary old (67 ± 2 yr) subjects. Arterial and venous blood samples, in conjunction with a thermodilution technique facilitated the measurement of quadriceps muscle blood flow and hematologic variables during incremental knee-extensor exercise. Pretraining, young and old subjects attained a similar maximal work rate (WRmax) (young = 27 ± 3, old = 24 ± 4 W) and similar maximal quadriceps O2 consumption (muscle V̇o2 max) (young = 0.52 ± 0.03, old = 0.42 ± 0.05 l/min), which increased equally in both groups posttraining (WRmax, young = 38 ± 1, old = 36 ± 4 W, Muscle V̇o2 max, young = 0.71 ± 0.1, old = 0.63 ± 0.1 l/min). Before training, muscle blood flow was ∼500 ml lower in the old compared with the young throughout incremental knee-extensor exercise. After 8 wk of knee-extensor exercise training, the young reduced muscle blood flow ∼700 ml/min, elevated arteriovenous O2 difference ∼1.3 ml/dl, and increased leg vascular resistance ∼17 mmHg·ml–1·min–1, whereas the old subjects revealed no training-induced changes in these variables. Together, these findings indicate that after 8 wk of small muscle mass exercise training, young and old subjects of equal initial metabolic capacity have a similar ability to increase quadriceps muscle WRmax and muscle V̇o2 max, despite an attenuated vascular and/or metabolic adaptation to submaximal exercise in the old.

Human femoral artery diameter in relation to knee extensor muscle mass, peak blood flow, and oxygen uptake

2000 ◽  
Vol 278 (1) ◽  
pp. H162-H167 ◽  
Author(s):  
G. Rådegran ◽  
B. Saltin
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Muscle Mass ◽  
Femoral Artery ◽  
Knee Extensor ◽  
Common Femoral Artery ◽  
Quadriceps Muscle ◽  
Cycle Exercise ◽  
Pulmonary Oxygen Uptake ◽  
The Common

It is not known whether the diameter of peripheral conduit arteries may impose a limitation on muscle blood flow and oxygen uptake at peak effort in humans, and it is not clear whether these arteries are dimensioned in relation to the tissue volume they supply or, rather, to the type and intensity of muscular activity. In this study, eight humans, with a peak pulmonary oxygen uptake of 3.90 ± 0.31 (range 2.29–5.03) l/min during ergometer cycle exercise, performed one-legged dynamic knee extensor exercise up to peak effort at 68 ± 7 W (range 55–100 W). Peak values for knee extensor blood flow (thermodilution) and oxygen uptake of 6.06 ± 0.74 (range 4.75–9.52) l/min and 874 ± 124 (range 590–1,521) ml/min, respectively, were achieved. Pulmonary oxygen uptake reached a peak of 1.72 ± 0.19 (range 1.54–2.33) l/min. Diameters of common and profunda femoral arteries determined by ultrasound Doppler were 10.6 ± 0.4 (range 8.2–12.7) and 6.0 ± 0.4 (range 4.5–8.0) mm, respectively. Thigh and quadriceps muscle volume measured by computer tomography were 10.06 ± 0.66 (range 6.18–10.95) and 2.36 ± 0.19 (range 1.31–3.27) liters, respectively. The common femoral artery diameter, but not that of the profunda branch, correlated with the thigh volume and quadriceps muscle mass. There were no relationships between either of the diameters and the absolute or muscle mass-related resting and peak values of blood flow and oxygen uptake, peak pulmonary oxygen uptake, or peak power output during knee extensor exercise. However, common femoral artery diameter correlated to peak pulmonary oxygen uptake during ergometer cycle exercise. In conclusion, common and profunda femoral artery diameters are sufficient to ensure delivery to the quadriceps muscle. However, the common branch may impose a limitation during ergometer cycle exercise.

Hemodynamics and O2 uptake during maximal knee extensor exercise in untrained and trained human quadriceps muscle: effects of hyperoxia

2004 ◽  
Vol 97 (5) ◽  
pp. 1796-1802 ◽  
Author(s):  
M. Mourtzakis ◽  
J. González-Alonso ◽  
T. E. Graham ◽  
B. Saltin
Keyword(s):  
Blood Flow ◽  
Peak Power ◽  
Fiber Type ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Capillary Density ◽  
Quadriceps Muscle ◽  
Peak Power Output ◽  
Vascular Conductance ◽  
Type Composition

To elucidate the potential limitations on maximal human quadriceps O2 capacity, six subjects trained (T) one quadriceps on the single-legged knee extensor ergometer (1 h/day at 70% maximum workload for 5 days/wk), while their contralateral quadriceps remained untrained (UT). Following 5 wk of training, subjects underwent incremental knee extensor tests under normoxic (inspired O2 fraction = 21%) and hyperoxic (inspired O2 fraction = 60%) conditions with the T and UT quadriceps. Training increased quadriceps muscle mass (2.9 ± 0.2 to 3.1 ± 0.2 kg), but did not change fiber-type composition or capillary density. The T quadriceps performed at a greater peak power output than UT, under both normoxia (101 ± 10 vs. 80 ± 7 W; P < 0.05) and hyperoxia (97 ± 11 vs. 81 ± 7 W; P < 0.05) without further increases with hyperoxia. Similarly, thigh peak O2 consumption, blood flow, vascular conductance, and O2 delivery were greater in the T vs. the UT thigh (1.4 ± 0.2 vs. 1.1 ± 0.1 l/min, 8.4 ± 0.8 vs. 7.2 ± 0.8 l/min, 42 ± 6 vs. 35 ± 4 ml·min−1·mmHg−1, 1.71 ± 0.18 vs. 1.51 ± 0.15 l/min, respectively) but were not enhanced with hyperoxia. Oxygen extraction was elevated in the T vs. the UT thigh, whereas arteriovenous O2 difference tended to be higher (78 ± 2 vs. 72 ± 4%, P < 0.05; 160 ± 8 vs. 154 ± 11 ml/l, respectively; P = 0.098) but again were unaltered with hyperoxia. In conclusion, the present results demonstrate that the increase in quadriceps muscle O2 uptake with training is largely associated with increases in blood flow and O2 delivery, with smaller contribution from increases in O2 extraction. Furthermore, the elevation in peak muscle blood flow and vascular conductance with endurance training seems to be related to an enhanced vasodilatory capacity of the vasculature perfusing the quadriceps muscle that is unaltered by moderate hyperoxia.

Vascular and metabolic response to isolated small muscle mass exercise: effect of age

2003 ◽  
Vol 285 (3) ◽  
pp. H1023-H1031 ◽  
Author(s):  
L. Lawrenson ◽  
J. G. Poole ◽  
J. Kim ◽  
C. Brown ◽  
P. Patel ◽  
...  
Keyword(s):  
Blood Flow ◽  
Muscle Mass ◽  
Vascular Resistance ◽  
Metabolic Response ◽  
Muscle Blood Flow ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Vasodilatory Response ◽  
Small Muscle ◽  
Effect Of Age

To determine the effect of age on quadriceps muscle blood flow (QMBF), leg vascular resistance (LVR), and maximum oxygen uptake (QV̇O2 max), a thermal dilution technique was used in conjunction with arterial and venous femoral blood sampling in six sedentary young (19.8 ± 1.3 yr) and six sedentary old (66.5 ± 2.1 yr) males during incremental knee extensor exercise (KE). Young and old attained a similar maximal KE work rate (WRmax) (young: 25.2 ± 2.1 and old: 24.1 ± 4 W) and QV̇O2 max (young: 0.52 ± 0.03 and old: 0.42 ± 0.05 l/min). QMBF during KE was lower in old subjects by ∼500 ml/min across all work rates, with old subjects demonstrating a significantly lower QMBF/W (old: 174 ± 20 and young: 239 ± 46 ml · min–1 · W–1). Although the vasodilatory response to incremental KE was ∼142% greater in the old (young: 0.0019 and old: 0.0046 mmHg · min · ml–1 · W–1), consistently elevated leg vascular resistance (LVR) in the old, ∼80% higher LVR in the old at 50% WR and ∼40% higher LVR in the old at WRmax (young: 44.1 ± 3.6 and old: 31.0 ± 1.7 mmHg · min · ml–1), dictated that during incremental KE the LVR of the old subjects was never less than that of the young subjects. Pulse pressures, indicative of arterial vessel compliance, were ∼36% higher in the old subjects across all work rates. In conclusion, well-matched sedentary young and old subjects with similar quadriceps muscle mass achieved a similar WRmax and QV̇O2 max during incremental KE. The old subjects, despite a reduced QMBF, had a greater vasodilatory response to incremental KE. Given that small muscle mass exercise, such as KE, utilizes only a fraction of maximal cardiac output, peripheral mechanisms such as consistently elevated leg vascular resistance and greater pulse pressures appear to be responsible for reduced blood flow persisting throughout graded KE in the old subjects.

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