有氧锻炼前后立位应激下血压变异性的比较

Comparison of blood pressure variability under orthostatic stress before and after aerobic training

目的阐明下体负压（ＬＢＮＰ）作用下血压变异性的特征，以及有氧锻炼是否对其有一定影响。方法用常规ＡＲ谱、时变ＡＲ谱、粗粒化谱分析（ＣＧＳＡ）及近似熵（ＡｐＥｎ）四种方法，分析六个月有氧锻炼前、后大学生在两种ＬＢＮＰ作用下的收缩压变异性（ＳＢＰＶ），并与一组中、长跑运动员的结果进行横向比较。结果ＬＢＮＰ作用时，ＳＢＰＶ信号谐波成份的总功率及低频段（ＬＦ）功率增大，分形成份的谱指数（无显著变化，而ＡｐＥｎ则呈持续升高变化。有氧锻炼后，ＬＢＮＰ作用下各种ＳＢＰＶ指标的响应变化较锻炼前并无显著差别。大学生组与运动员组之间亦无显著差别。结论ＳＢＰＶ信号与心率变异性（ＨＲＶ）迥然不同：ＬＢＮＰ作用下，ＳＢＰＶ的ＬＦ成份被进一步激活，信号的复杂度显著升高；但ＳＢＰＶ信号的这种特征性变化并不受有氧锻炼的影响。

Objective The aims of the present study were to investigate the signal characteristics of short term systolic blood pressure variability (SBPV) during lower body negative pressure (LBNP) testing and to see the effect of aerobic training on them. Methods The SBPV signals during both supine and upright seated LBNP tests, obtained from a group of 8 student subjects before and after a 6 mon aerobic training, as well as from 6 athletes (medium and long distance runners) were analyzed by conventional and dynamic autoregressive (AR) spectral analyses, coarse graining spectral analysis (CGSA), and approximate entropy (ApEn) measurement. Results During supine resting, SBPV showed a typical pattern of primarily low frequency oscillations with spectral exponent β being ～2. During LBNP tests, the total spectral power (TP) and low frequency power (LF) of the harmonic component, as well as the ApEn value of SBPV signals showed significant increases, whereas the slope β of the fractal component was unchanged for SBPV. There was no significant change in the above stated spectral and non linear indexes of SBPV under LBNP after aerobic training. Conclusion These data indicate that there are important differences between SBPV and heart rate variability (HRV) signals during LBNP test. For SBPV, the LF power component is further activated, the process of regulation appears to be more complicated under orthostatic stress, and the signal characteristics are not changed after aerobic training.