Cerebral hemodynamics response to low intensity physical exercise
Kulikov, V.P.; Doronina, N.L.; Gatal'skiĭ, K.K.
Rossiiskii Fiziologicheskii Zhurnal Imeni I.M. Sechenova 94(7): 790-798
2008
ISSN/ISBN: 0869-8139 PMID: 18767391 Document Number: 620015
The aim of this research was to study the cerebral hemodynamics reaction to step increase of physical exercises intensity during bicycle ergometer test in young healthy male subjects. Hemodynamics parameters were registered with the transcranial Doppler ultrasonography of middle cerebral artery (MCA) prior to the study and during the last seconds of every step of physical exercise. Cerebral hemodynamics response to physical exercise was characterized by a significant increase of peak systolic blood velocity in the MCA up to 0.25 W/kg of the body weight (90 rpm with regard to 0 W/kg) without further increase of blood velocity in the same physical exercise becoming more intensive up to 0.5 W/kg of the body weight. The stabilization mechanism of blood velocity in cerebral arteries in case of physical exercise increase and, hence, the autoregulation mechanism of cerebral circulation means that the increase of regional cerebral vascular resistance depends on the value of arterial pressure. The autoregulation mechanism of cerebral circulation starts working with he exercise intensity of 0.25 W/kg and the value of systolic blood pressure about 140-145 mm Hg.