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观察了－６．６７ｋＰａ下体负压（ＬＢＮＰ）持续作用期间人心率变异性（ＨＲＶ）、血压变异性（ＳＢＰＶ）谱的变化，并探讨了谱特征与心血管反应之间的关系。结果表明：耐力良好者ＨＲＶ谱的高频峰功率（ＨＦＨＲＶ）显著降低，归一化高频参数（ＨＦＨＲＶ，ｎ）与低频参数（ＬＦＨＲＶ，ｎ）分别呈明确的降低或升高变化；ＳＢＰＶ谱的低频峰功率（ＬＦＳＢＰＶ）ＬＢＮＰ作用时降低，后又回升，至实验终止时已超出对照水平。ＬＢＮＰ作用初期，耐力不良被试者ＨＲＶ、ＳＢＰＶ谱特征的变化趋势与耐力良好者相同，但在出现晕厥前症状时，ＬＦＳＢＰＶ及ＬＦＳＢＰＶ，ｎ均有较大幅度的降低。上述结果提示：耐力不良被试者心血管反应失代偿主要与外周血管交感神经活动水平的迅速降低有关。
The changes of HRV and SBPV during the continuous effect of -6.67 kPa LBNP were observed, and the relationship between spectral characteristics and cardiovascular responses was also discussed. The results showed that HFHRV of HRV spectrum of endurance patients decreased significantly, and the changes of normalized HFHRV, n and LFHRV, n showed a clear decrease or increase respectively. Peak power (LFSBPV) LBNP decreased when the effect, and then rose, to the end of the experiment has exceeded the control level. In the early stage of LBNP, the characteristics of HRV and SBPV in endurance poor subjects were similar to those in endurance. However, LFSBPV and LFSBPV, n both had a significant decrease in the pre-syncope symptoms. The above results suggest that cardiovascular decompensation in subjects with poor endurance is mainly due to the rapid decrease of peripheral sympathetic nerve activity.