准备运动与放松运动对剧烈运动中及运动后颈总动脉血流速度的影响

８名男性大学生参加了下列３组实验：（１）单纯５分钟的剧烈运动（大于９０％ｏｆＶＯ２ｍａｘ）；（２）５分钟的准备运动（５０％ｏｆＶＯ２ｍａｘ）后再进行上述剧烈运动；（３）上述剧烈运动后再进行５分钟的放松运动（５５％ｏｆＶＯ２ｍａｘ）。在上述实验的同时，检测了每位被试者的颈总动脉血流平均速度（平均ＶＣＣＡ）、心率（ｆｃ）、左肱动脉平均血压（Ｐｍ），并根据血流速度参数计算出反映脑血流阻力的指标———阻抗指数（ＲＩ）。结果显示：在５分钟的剧烈运动中，不论有否准备运动，上述４种参数均明显增加。在准备运动中，平均ＶＣＣＡ和ｆｃ均有所增加，ＲＩ的增加几乎达到了剧烈运动时的水平。剧烈运动后，Ｐｍ和ｆｃ很快恢复，放松运动中这两个指标有所恢复。但是平均ＶＣＣＡ和ＲＩ在放松运动中保持着剧烈运动时的高水平。准备运动中阻抗指数明显增加提示脑血流阻力增加，这可防止由于颈总动脉平均血流速度和心率的增加而引起脑血流的过多增加（尤其是对那些有脑血管缺陷的人），有利于机体接着进行剧烈的运动。本研究中的放松运动可减缓颈总动脉血流平均速度等几种生理指标在剧烈运动后的恢复速度，使剧烈运动后机体（尤其是心脑血管调节功能差的人）的生理功能逐渐得到恢复，?

Influences of warm-up and cool-down on blood flow velocity in the common carotid artery in man during and after streneous exercise

Eight male students with 1_2 years regular exercise underwent a streneous exercise under following three different conditions:(1)no warm_up or cool_down,(2)warm_up,50% of VO 2max ,(3)cool_down,55% of VO 2max .Mean blood flow velocity in the common carotid artery(mean V CCA ) was measured to see whether maneuver of warm_up and cool_down affect mean V CCA or its recovery during and after streneous exercise,respectively.Resistance index(RI),heart rate(f c) and mean blood pressure(P m) in the left brachial artery were determined simultaneously.Mean V CCA ,RI,f c and P m increased during the streneous exercise,but no differences in these increases were found between the streneous exercisees with or without warm_up.During the warm_up period,mean V CCA and f c increased moderately,RI increased similar to the level of streneous exercise.After 5_min streneous exercise,f c and P m recovered rapidly to baseline.During the cool_down period,these two parameters recovered significantly, whereas,mean V CCA and RI remained as high as during the streneous exercise.Immediate increase in RI in the warm_up period reflects an increase in the cerebral flow resistance,this increase may prevent cerebral over_perfusion caused by the increases in f c and V CCA ,it is advantageous to human body being ready to sudden streneous exercise,especially for some subjects with cerebrovascular defects. The lower intensity of cool_down in this study slowed down the recovery of above four physiologic parameters after streneous exercise.Therefore,especially for some subjects whose regulatory functions of circulation are not very well,cool_down is advantageous for human body to recover from sudden streneous exercise,and to avoid sudden decrease of CBF after sudden streneous exercise as reported by Lee et al.(1991) and by Sollmann et al.(1989).