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Cerebral blood flow during exercise: mechanisms of regulation.

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  • Ref Cerebral blood flow during exercise: mechanisms of regulation.

    Cerebral blood flow during exercise: mechanisms of regulation.
    Ogoh S1, Ainslie PN.

    Abstract

    The response of cerebral vasculature to exercise is different from other peripheral vasculature; it has a small vascular bed and is strongly regulated by cerebral autoregulation and the partial pressure of arterial carbon dioxide (Pa(CO(2))). In contrast to other organs, the traditional thinking is that total cerebral blood flow (CBF) remains relatively constant and is largely unaffected by a variety of conditions, including those imposed during exercise. Recent research, however, indicates that cerebral neuronal activity and metabolism drive an increase in CBF during exercise. Increases in exercise intensity up to approximately 60% of maximal oxygen uptake produce elevations in CBF, after which CBF decreases toward baseline values because of lower Pa(CO(2)) via hyperventilation-induced cerebral vasoconstriction. This finding indicates that, during heavy exercise, CBF decreases despite the cerebral metabolic demand. In contrast, this reduced CBF during heavy exercise lowers cerebral oxygenation and therefore may act as an independent influence on central fatigue. In this review, we highlight methodological considerations relevant for the assessment of CBF and then summarize the integrative mechanisms underlying the regulation of CBF at rest and during exercise. In addition, we examine how CBF regulation during exercise is altered by exercise training, hypoxia, and aging and suggest avenues for future research.
    https://www.ncbi.nlm.nih.gov/pubmed/19729591

    Effects of Strenuous Exercise on Visual Perception Are Independent of Visual Resolution
    S Ando et al. Physiol Behav 106 (2), 117-121. 2012

    The premotor time during exercise at 40% peak VO(2) was not different from that at rest. In contrast, the premotor time during exercise at 75% peak VO(2) was significantly longer than that at rest (p=0.018). The increase in the premotor time was observed irrespective of eccentricity, and the detrimental effects were not exaggerated toward the periphery of the visual field. The motor time was not affected by exercise. The current findings suggest that the detrimental effects of strenuous exercise on visual perception are independent of visual resolution.
    https://www.ncbi.nlm.nih.gov/labs/articles/22285211/

    Exercise increases blood flow to locomotor, vestibular, cardiorespiratory and visual regions of the brain in miniature swine
    Michael D Delp et al 2001

    DISCUSSION

    The present study demonstrates that blood flow to the brain increases during submaximal and maximal exercise (Fig. 1). The increase, however, is not uniformly distributed throughout the brain. As has previously been shown by others (Foreman et al. 1976; Manohar, 1986, 1987; Manohar & Goetz, 1998), there is no change in the perfusion rate to cortical areas of the cerebrum associated with motor and somatosensory function during locomotor exercise. This study extends these observations to indicate that blood flow to regions of the brain related to hearing and smell are also unaltered by physical exertion. However, perfusion is elevated to regions of the brain that are related to locomotion (subcortical locomotor regions), the maintenance of equilibrium, cardiorespiratory control and vision. Furthermore, the data indicate that blood flow increases as a function of exercise intensity to several areas of the brain associated with integrating sensory input and motor output (anterior and dorsal cerebellar vermis) and the maintenance of equilibrium (vestibular nuclear area of medulla).
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2278667/

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    New Horizons in Neurovascular Coupling: A Bridge Between Brain Circulation ...
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    "Evolution is a tinkerer not an engineer" F.Jacob
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  • #2
    Promoting Motor Function by Exercising the Brain
    Stephane Perrey
    Brain Sci. 2013 Mar; 3(1): 101–122.
    Published online 2013 Jan 25. doi: 10.3390/brainsci3010101

    Abstract

    Exercise represents a behavioral intervention that enhances brain health and motor function. The increase in cerebral blood volume in response to physical activity may be responsible for improving brain function. Among the various neuroimaging techniques used to monitor brain hemodynamic response during exercise, functional near-infrared spectroscopy could facilitate the measurement of task-related cortical responses noninvasively and is relatively robust with regard to the subjects’ motion. Although the components of optimal exercise interventions have not been determined, evidence from animal and human studies suggests that aerobic exercise with sufficiently high intensity has neuroprotective properties and promotes motor function. This review provides an insight into the effect of physical activity (based on endurance and resistance exercises) on brain function for producing movement. Since most progress in the study of brain function has come from patients with neurological disorders (e.g., stroke and Parkinson’s patients), this review presents some findings emphasizing training paradigms for restoring motor function.
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4061835/
    Marcel

    "Evolution is a tinkerer not an engineer" F.Jacob
    "Without imperfection neither you nor I would exist" Stephen Hawking

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