The Influence Of Age On The Regulation Of Cerebral Blood Flow During Dynamic Exercise In Humans

Cerebral blood flow (CBF) in humans was measured at rest and during dynamic exercise on a cycle ergometer corresponding to 56% (range 27–85) of maximal O2 uptake (VO2max). Exercise bouts were performed by 16 male and female subjects, lasted 15 min each, and were carried out in a semisupine position. CBF (133Xe clearance) was expressed as the initial slope index (ISI) and as the first compartment flow (F1). CBF at rest [ISI, 58 (range 45–73); F1, 76 (range 55–98) ml.100 g-1.min-1] increased during exercise [ISI to 79 (57–94) and F1 to 118 (75–164) ml.100 g-1.min-1, P less than 0.01]. CBF did not differ significantly between work loads from 32 (24–33) to 86% (74–96) of VO2max (n = 10). During exercise, mean arterial pressure increased from 84 (60–100) to 101 (78–124) Torr (P less than 0.01) and PCO2 remained unchanged [5.1 (4.6–5.6) vs. 5.4 (4.4–6.3) kPa, n = 6]. These results demonstrate a median increase of 31% (0–87) in CBF by ISI and a median increase of 58% (0–133) in CBF by F1 during dynamic exercise in humans.

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Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans

Journal of Applied Physiology ◽

10.1152/jappl.1997.83.4.1383 ◽

1997 ◽

Vol 83 (4) ◽

pp. 1383-1388 ◽

Cited By ~ 188

Author(s):

G. Rådegran

Keyword(s):

Blood Flow ◽

Femoral Artery ◽

Coefficient Of Variation ◽

Knee Extensor ◽

Dynamic Exercise ◽

Artery Blood Flow ◽

Ultrasound Doppler ◽

Femoral Artery Blood Flow ◽

Human Limb ◽

Exercise In Humans

Rådegran, G. Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans. J. Appl. Physiol.83(4): 1383–1388, 1997.—Ultrasound Doppler has been used to measure arterial inflow to a human limb during intermittent static contractions. The technique, however, has neither been thoroughly validated nor used during dynamic exercise. In this study, the inherent problems of the technique have been addressed, and the accuracy was improved by storing the velocity tracings continuously and calculating the flow in relation to the muscle contraction-relaxation phases. The femoral arterial diameter measurements were reproducible with a mean coefficient of variation within the subjects of 1.2 ± 0.2%. The diameter was the same whether the probe was fixed or repositioned at rest (10.8 ± 0.2 mm) or measured during dynamic exercise. The blood velocity was sampled over the width of the diameter and the parabolic velocity profile, since sampling in the center resulted in an overestimation by 22.6 ± 9.1% ( P< 0.02). The femoral arterial Doppler blood flow increased linearly ( r = 0.997, P < 0.001) with increasing load [Doppler blood flow = 0.080 ⋅ load (W) + 1.446 l/min] and was correlated positively with simultaneous thermodilution venous outflow measurements ( r = 0.996, P < 0.001). The two techniques were linearly related (Doppler = thermodilution ⋅ 0.985 + 0.071 l/min; r = 0.996, P < 0.001), with a coefficient of variation of ∼6% for both methods.

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Cerebral Blood Flow during Dynamic Exercise Correlates with Blood Pressure in Autonomic Brain Regions

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000519212.46630.43 ◽

2017 ◽

Vol 49 (5S) ◽

pp. 824

Author(s):

Mikio Hiura ◽

Akitaka Muta ◽

Muneyuki Sakata ◽

Satoshi Wagatsuma ◽

Tetsurou Tago ◽

...

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Brain Regions ◽

Dynamic Exercise

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Middle cerebral artery blood velocity and cerebral blood flow and O2 uptake during dynamic exercise

Journal of Applied Physiology ◽

10.1152/jappl.1993.74.1.245 ◽

1993 ◽

Vol 74 (1) ◽

pp. 245-250 ◽

Cited By ~ 111

Author(s):

P. L. Madsen ◽

B. K. Sperling ◽

T. Warming ◽

J. F. Schmidt ◽

N. H. Secher ◽

...

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Transcranial Doppler Sonography ◽

Dynamic Exercise ◽

Global Average ◽

Proportional Increase ◽

Exercise Induced

Results obtained by the 133Xe clearance method with external detectors and by transcranial Doppler sonography (TCD) suggest that dynamic exercise causes an increase of global average cerebral blood flow (CBF). These data are contradicted by earlier data obtained during less-well-defined conditions. To investigate this controversy, we applied the Kety-Schmidt technique to measure the global average levels of CBF and cerebral metabolic rate of oxygen (CMRO2) during rest and dynamic exercise. Simultaneously with the determination of CBF and CMRO2, we used TCD to determine mean maximal flow velocity in the middle cerebral artery (MCA Vmean). For values of CBF and MCA Vmean a correction for an observed small drop in arterial PCO2 was carried out. Baseline values for global CBF and CMRO2 were 50.7 and 3.63 ml.100 g-1.min-1, respectively. The same values were found during dynamic exercise, whereas a 22% (P < 0.0001) increase in MCA Vmean was observed. Hence, the exercise-induced increase in MCA Vmean is not a reflection of a proportional increase in CBF.

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CEREBRAL BLOOD FLOW IN MAN DURING DYNAMIC EXERCISE

Medicine & Science in Sports & Exercise ◽

10.1249/00005768-198004001-00015 ◽

1980 ◽

Vol 21 (Supplement) ◽

pp. S3

Author(s):

S. N. Thomas ◽

T. Schroeder ◽

N. H. Secher ◽

J. H. Mitchell

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Dynamic Exercise

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CEREBRAL BLOOD FLOW IN MAN DURING DYNAMIC EXERCISE

Medicine & Science in Sports & Exercise ◽

10.1249/00005768-198904001-00015 ◽

1989 ◽

Vol 21 (Supplement) ◽

pp. S3

Author(s):

S. N. Thomas ◽

T. Schroeder ◽

N. H. Secher ◽

J. H. Mitchell

Keyword(s):

Blood Flow ◽

Cerebral Blood Flow ◽

Dynamic Exercise

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Faculty Opinions recommendation of Central command contributes to increased blood flow in the noncontracting muscle at the start of one-legged dynamic exercise in humans.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.14267213.15779391 ◽

2012 ◽

Author(s):

James Duffin

Keyword(s):

Blood Flow ◽

Dynamic Exercise ◽

Central Command ◽

Increased Blood Flow ◽

Exercise In Humans

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Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

The Journal of Physiology ◽

10.1111/j.1469-7793.2000.t01-2-00305.x ◽

2000 ◽

Vol 524 (1) ◽

pp. 305-313 ◽

Cited By ~ 92

Author(s):

Robert Boushel ◽

Henning Langberg ◽

Simon Green ◽

Dorthe Skovgaard ◽

Jens Bülow ◽

...

Keyword(s):

Blood Flow ◽

Dynamic Exercise ◽

Calf Muscle ◽

Exercise In Humans

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Effect of healthy aging on cerebral blood flow, CO2 reactivity, and neurovascular coupling during exercise

Journal of Applied Physiology ◽

10.1152/japplphysiol.00050.2018 ◽

2018 ◽

Vol 125 (6) ◽

pp. 1917-1930 ◽

Cited By ~ 7

Author(s):

Daniela Nowak-Flück ◽

Philip N. Ainslie ◽

Anthony R. Bain ◽

Amar Ahmed ◽

Kevin W. Wildfong ◽

...

Keyword(s):

Carbon Dioxide ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Carotid Artery ◽

Internal Carotid Artery ◽

Healthy Aging ◽

Internal Carotid ◽

Neurovascular Coupling ◽

Dynamic Exercise ◽

Older Individuals

We sought to make the first comparisons of duplex Doppler ultrasonography-derived measures of cerebral blood flow during exercise in young and older individuals and to assess whether healthy aging influences the effect of exercise on neurovascular coupling (NVC) and cerebral vascular reactivity to changes in carbon dioxide (CVRco2). In 10 healthy young (23 ± 2 yr; mean ± SD) and 9 healthy older (66 ± 3 yr) individuals, internal carotid artery (ICA) and vertebral artery (VA) blood flows were concurrently measured, along with middle and posterior cerebral artery mean blood velocity (MCAvmean and PCAvmean). Measures were made at rest and during leg cycling (75 W and 35% maximum aerobic workload). ICA and VA blood flow during dynamic exercise, undertaken at matched absolute (ICA: young 336 ± 95, older 352 ± 155; VA: young 95 ± 43, older 100 ± 30 ml/min) and relative (ICA: young 355 ± 125, older 323 ± 153; VA: young 115 ± 48, older 110 ± 32 ml/min) intensities, were not different between groups ( P > 0.670). The PCAvmean responses to visual stimulation (NVC) were blunted in older versus younger group at rest (16 ± 6% vs. 23 ± 7%, P < 0.026) and exercise; however, these responses were not changed from rest to exercise in either group. The ICA and VA CVRco2 were comparable in both groups and unaltered during exercise. Collectively, our findings suggest that 1) ICA and VA blood flow responses to dynamic exercise are similar in healthy young and older individuals, 2) NVC is blunted in healthy older individuals at rest and exercise but is not different between rest to exercise in either group, and 3) CVRco2 is similar during exercise in healthy young and older groups. NEW & NOTEWORTHY Internal carotid artery and vertebral artery blood flow responses to dynamic exercise are similar in healthy young and older individuals. Neurovascular coupling and cerebrovascular carbon dioxide reactivity, two key mechanisms mediating the cerebral blood flow responses to exercise, are generally unaffected by exercise in both healthy young and older individuals.

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