The realtime cerebral hemodynamics was noninvasively observed in ergometeric exercise test 50W, 3 minutes on 5 young healty adults. The blood flow velocity of middle cerebral artery (MCA) was monitored by a transcranial Doppler method (TCD) and recorded at 30- second intervals. Simultaneously, the brachial blood pressure was measured every minute by electric cuff pressure method. As the result, MCA mean flow velocity was increased 33% and the blood pressure was increased 15%. On the other hand, the increasing ratio of cardiac output was previously reported to be about 45〜60% in the corresponding exercise test. In comparison with increasing ratio of 1.33 in MCA blood flow, 1.15 in blood pressure and 1.6 in cardiac output, the cerebral circulation was controled by changing about 15% decrease in cerebral vascular resistance in spite of about 30% decrease in systemic circulation resistance in this exercise.
　It was suggested quantitatively that control mechanism of cerebral circulation is different from control mechanism of systemic circulation.

DESCENTE SPORTS SCIENCE Vol.17/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE