Middle cerebral artery flow velocity and pulse pressure during dynamic exercise in humans

Ogoh, Shigehiko; Fadel, Paul J.; Zhang, Rong; Selmer, Christian; Jans, Øivind; Secher, Niels H.; Raven, Peter B.

doi:10.1152/ajpheart.00979.2004

Cited by 107 publications

(134 citation statements)

References 28 publications

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“…This magnitude of increase is similar to that observed by other authors using transcranial Doppler to assess blood flow velocity in the MCA during exercise (Hellstrom et al 1996;Jorgensen et al 1992;Linkis et al 1995;Moraine et al 1993;Ogoh et al 2005). However, MCAv at 70 % HRR was similar or slightly reduced compared with that observed at 30 % HRR.…”

Section: Discussionsupporting

confidence: 90%

Cerebral blood flow and cerebrovascular reactivity at rest and during sub-maximal exercise: Effect of age and 12-week exercise training

Murrell

Cotter

Thomas

et al. 2012

AGE

165

180

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Chronic reductions in cerebral blood flow (CBF) and cerebrovascular reactivity to CO 2 are risk factors for cerebrovascular disease. Higher aerobic fitness is associated with higher CBF at any age; however, whether CBF or reactivity can be elevated following an exercise training intervention in healthy individuals is unknown. The aim of this study was to assess the effect of exercise training on CBF and cerebrovascular reactivity at rest and during exercise in young and older individuals. Ten young (23±5 years; body mass index ) previously sedentary individuals breathed 5 % CO 2 for 3 min at rest and during steady-state cycling exercise (30 and 70 % heart rate range (HRR)) prior to and following a 12-week aerobic exercise intervention. Effects of training on middle cerebral artery blood velocity (MCAv) at rest were unclear in both age groups. The absolute MCAv response to exercise was greater in the young (9 and 9 cm s −1 (30 and 70 % HRR, respectively) vs. 5 and 4 cm s −1 (older), P<0.05) and was similar following training. Cerebrovascular reactivity was elevated following the 12-week training at rest (2.87±0.76 vs. 2.54± 1.12 cm s −1 mm Hg −1 , P00.01) and during exercise, irrespective of age. The finding of a training-induced elevation in cerebrovascular reactivity provides further support for exercise as a preventative tool in cerebrovascular and neurological disease with ageing.

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Section: Discussionsupporting

confidence: 90%

Cerebral blood flow and cerebrovascular reactivity at rest and during sub-maximal exercise: Effect of age and 12-week exercise training

Murrell

Cotter

Thomas

et al. 2012

AGE

165

180

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“…Maintained CBF during exercise with aging: influence of blood pressure During cycling exercise, MAP and SBP increase, combined with a slight decrease or no change in DBP (Rowell 1993;Ogoh et al 2005b). In the present study, both YA and OA increased MAP and SBP (Table 2, P < 0.001) at each workload until the cessation of exercise.…”

Section: Discussionmentioning

confidence: 99%

“…and Sheel 2007; Pott et al 1996;Hellstrom et al 1996;Madsen et al 1993;Ogoh et al 2005b). This increase is reflected with a parallel increase in regional CBF, neuronal activity and metabolism (reviewed in Ogoh and Ainslie 2009).…”

mentioning

confidence: 99%

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Marsden

Haykowsky

Smirl

et al. 2011

AGE

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Cerebral blood flow (CBF) increases from rest to ∼60% of peak oxygen uptake (VO 2peak ) and thereafter decreases towards baseline due to hyperventilation-induced hypocapnia and subsequent cerebral vasoconstriction. It is unknown what happens to CBF in older adults (OA), who experience a decline in CBF at rest coupled with a blunted ventilatory response during VO 2peak . In 14 OA (71±10 year) and 21 young controls (YA; 23±4 years), we hypothesized that OA would experience less hyperventilationinduced cerebral vasoconstriction and therefore an attenuated reduction in CBF at VO 2peak . Incremental exercise was performed on a cycle ergometer, whilst bilateral middle cerebral artery blood flow velocity (MCA V mean ; transcranial Doppler ultrasound), heart rate (HR; ECG) and end-tidal PCO 2 (P ET CO 2 ) were monitored continuously. Blood pressure (BP) was monitored intermittently. From rest to 50% of VO 2peak , despite greater elevations in BP in OA, the change in MCA V mean was greater in YA compared to OA (28% vs. 15%, respectively; P<0.0005). In the YA, at intensities >70% of VO 2peak , the hyperventilationinduced declines in both P ET CO 2 (14 mmHg (YA) vs. 4 mmHg (OA); P<0.05) and MCA V mean (−21% (YA) vs. −7% (OA); P<0.0005) were greater in YA compared to OA. Our findings show (1), from rest-tomild intensity exercise (50% VO 2peak ), elevations in CBF are reduced in OA and (2) age-related declines in hyperventilation during maximal exercise result in less hypocapnic-induced cerebral vasoconstriction.

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“…The fluid was maintained at room temperature (20°C). Elevating the saline reservoir 105-110 cm above the anastomosis produced a steady pressure of 78 mm Hg, which is similar to the intracranial mean arterial pressure in a healthy adult during exercise (Ogoh et al 2005). The volume of fluid that flowed through the anastomosis in 30 s was measured using a calibrated cylinder.…”

Section: Ex Vivo Experimentsmentioning

confidence: 87%

Fluid dynamic characterization of a novel branching anastomosis design

Samuelson

Nair

Snyder

et al. 2015

International Biomechanics

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Geometric characteristics of a vascular anastomosis can have important biomechanical impacts, particularly in the hemodynamic context of wall shear stress (WSS). In this study, we propose a new branching anastomosis design, the Hybrid anastomosis, to connect a donor vessel to two recipient vessels. The central obstruction characteristic of the traditional Figure 8 anastomosis is mitigated by creating a recessed lumen at the bifurcation. Chicken vessels were used to create and test three Figure 8 and three Hybrid anastomoses ex vivo. Computational fluid dynamics (CFD) simulations of idealized anastomosis designs were then used to verify the experiments and further studied the WSS and WSS gradient (WSSG) profiles of the designs. Experimental results showed increased flow through the Hybrid anastomosis (0.40 ml/s vs. 0.23 ml/s). The mean suture time averaged 20 and 28 min for the Figure 8 and Hybrid anastomoses, respectively. CFD simulations agreed with the experiments; the simulations showed lower flow resistance in the Hybrid anastomosis (1.89 kPa-s/ml vs. 6.77 kPa-s/ml). Most importantly, a set of more physiologically realistic simulations showed that the Hybrid anastomosis reduced WSS and WSSG by over 60% as compared to the Figure 8. Results demonstrated that the proposed Hybrid anastomosis can be created on a comparable surgical time scale (and from the same initial vasculature) as compared to the Figure 8 anastomosis, while decreasing flow resistance and reducing WSS and WSSG considerably. These findings support that the new Hybrid anastomosis may represent a favorable surgical alternative to the Figure 8 design.

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Middle cerebral artery flow velocity and pulse pressure during dynamic exercise in humans

Cited by 107 publications

References 28 publications

Cerebral blood flow and cerebrovascular reactivity at rest and during sub-maximal exercise: Effect of age and 12-week exercise training

Cerebral blood flow and cerebrovascular reactivity at rest and during sub-maximal exercise: Effect of age and 12-week exercise training

Aging blunts hyperventilation-induced hypocapnia and reduction in cerebral blood flow velocity during maximal exercise

Fluid dynamic characterization of a novel branching anastomosis design

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