[The effect of physical stress on the blood flow velocity in the middle cerebral artery. A transcranial Doppler sonographic study].
Changes in blood flow velocity of the middle cerebral artery (MCA) were measured by transcranial Doppler Sonography in 10 healthy subjects during a 10-minute period of moderate bicycle exercise. During physical exercise, a marked increase in heart rate (+63%) und ventilation rate (+48%) and a moderate increase in mean arterial blood pressure (+16%) were found. The end tidal carbon dioxide partial pressure rose in all cases by a mean value of 6.7 mmHg. The MCA flow velocity increased from 62 cm/s to 75 cm/s by 13 cm/s or 21% (mean values). When corrected to a standard pCO2 of 40 mmHg no significant changes in flow velocities (-1 cm/s) were found. Our Doppler sonographic findings indicate that during moderate physical exercises the MCA flow velocity - and the cerebral circulation - are regulated by the carbon dioxide partial pressure and not by cardiac output.
Briebach
T
T
Abteilung für Neurologie, Klinikum der Johann-Wolfgang-Goethe-Universität, Frankfurt.
Laubenberger
J
J
Fischer
P A
PA
D000328:Adult; D001783:Blood Flow Velocity; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D002536:Cerebral Arteries; D002560:Cerebrovascular Circulation; D004453:Echoencephalography / Q000379:methods*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male
D002245:Carbon Dioxide
Der Einfluss körperlicher Belastung auf die Flussgeschwindigkeit in der Arteria cerebri media. Eine transkraniell dopplersonographische Untersuchung.