Cerebral hemodynamic reactions to low-intensity physical exercise |
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Authors: | V P Kulikov N L Doronina K K Gatal’skii |
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Institution: | (1) Federal Agency for Health and Social Development, Altai State Medical University, Altai Region, Russia;(2) Altai Branch, Research Institute of Physiology, Siberian Branch, Russian Academy of Medical Sciences, 40 Lenin Prospekt, 656038 Barnaul, Altai Region, Russia |
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Abstract: | Cerebral hemodynamic reactions to light physical exercise increasing stepwise on a bicycle ergometer were studied in healthy
young male subjects. Hemodynamic parameters were measured by transcranial Doppler ultrasonography from the middle cerebral
artery (MCA) before the start of the study and during the last few seconds of each exercise step. Cerebral hemodynamic reactions
to physical exercise were characterized by a significant increase in systolic blood flow rate in the middle cerebral artery
only at exercise levels of about 0.25 W/kg body weight (90 rpm at 0 W/kg) with no further increase in the blood flow rate
with increases in loading to 0.5 W/kg body weight. The mechanism stabilizing blood flow rate in the cerebral arteries as physical
exercise increased and, thus, the mechanism of cerebral circulatory autoregulation consisted of a arterial pressure-dependent
increase in regional cerebral vascular resistance. The threshold at which the cerebral blood flow rate autoregulatory mechanism
was triggered in normal subjects corresponded to a loading of about 0.25 W/kg and a systolic arterial pressure of about 140–145
mmHg.
Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 94, No. 7, pp. 790–798, July, 2008. |
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Keywords: | cerebral hemodynamics autoregulation physical exercise |
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