Hellström G, Wahlgren N G
Department of Neurology, Karolinska Institute, Stockholm, Sweden.
Neurosurg Rev. 1993;16(2):151-6. doi: 10.1007/BF00258249.
The effect on the middle cerebral artery blood flow velocity (VMCA) of moderate and hard physical exercise on an ergometer cycle was examined in 10 healthy volunteers using transcranial Doppler sonography (TCD). During exercise, the heart rate increased by 136% and the systolic blood pressure by 37% (mean values). During initial moderate exercise, VMCA increased by 51%; in a following period of maximal physical work, VMCA decreased again by 20% in 9 of 10 volunteers although the heart rate continued to increase by 10% and the systolic blood pressure by 5% (mean values). Constriction of the MCA may explain the initial increase of VMCA, suggesting a role for large cerebral arteries in autoregulation. Our data indicate that the subsequent decrease of VMCA is caused by arteriolar constriction, a likely cause of which was hyperventilation during the excessive work period.
使用经颅多普勒超声（TCD）对10名健康志愿者进行了研究，以检测在测力计自行车上进行中等强度和高强度体育锻炼对大脑中动脉血流速度（VMCA）的影响。运动期间，心率平均增加了136%，收缩压平均增加了37%。在最初的中等强度运动期间，VMCA增加了51%；在随后的最大体力劳动阶段，10名志愿者中有9人的VMCA再次下降了20%，尽管心率继续增加了10%，收缩压继续增加了5%（平均值）。大脑中动脉（MCA）的收缩可能解释了VMCA最初的增加，这表明大脑大动脉在自动调节中发挥作用。我们的数据表明，VMCA随后的下降是由小动脉收缩引起的，其可能原因是过度工作期间的过度通气。
