心率/血压变异性与压力反射敏感度的年龄依赖性

目的 比较中年与青年男子心率变异性（ＨＲＶ）、收缩压变异性（ＳＢＰＶ）和压力反射敏感度（ＢＲＳ）的差别,探讨不同年龄组心血管自主神经调节的特点。方法 用自回归模型方法计算仰卧位与站立位ＨＲＶ和ＳＢＰＶ的谱指标,用序费法计算ＢＲＳ,并分析其间的相关性。结果 中年组两种体位下的ＨＲＶ谱指标及仰卧位时的ＢＲＳ均显著低于青年组（Ｐ〈０．０５,或Ｐ〈０．０１）。由仰卧位转为站立位后,中年组ＨＲＶ的总功率（Ｔ

Age Dependency of Heart Rate Variability,Blood Pressure Variability and Baroreflex Sensitivity.

Objective To compare the cardiovascular autonomic regulatory function between young and middle aged male subjects and to assess the effects of aging. Method Spectral indices of short term heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreflex sensitivity (BRS) in both supine and upright positions were obtained by AR spectral analysis and the sequential method, respectively, for both groups. Result HRV spectral indices in both supine and upright, and the BRS in supine were lower in the middle aged subjects than in the young subjects (P<0.05, or P<0.01). From supine to upright position total power (TP), low frequency power (LF) and high frequency power (HF) of HRV spectrum did not show any significant changes in the middle aged subjects, whereas in the young subjects typical changes were observed. SBPV spectral indices did not show significant differences between the two groups in both supine and upright positions. However, SBPV HF was an exception, being lower in supine position in the middle aged than in the young subjects (P<0.01). For the young subjects, in supine position, BRS was correlated with LF and HF of HRV, respectively, and the spectral indices of HRV in supine position were also correlated with their corresponding indices in upright position. For the middle aged subjects these correlations did not exist. Conclusion In the middle aged, both HRV and BRS are reduced and the correlations between HRV indices and BRS are not existent. However, the short term blood pressure variability seems to be not age dependent. It suggests that different regulatory mechanisms might account for it and that under resting condition the feed forward regulation from HRV to SBPV might be unimportant.