Wang S Y, Zhang L F, Wang X B, Cheng J H
Department of Aerospace Physiology, The Fourth Military Medical University, Xi'an, China.
Space Med Med Eng (Beijing). 2000 Oct;13(5):318-22.
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.
目的。比较青年男性与中年男性受试者的心血管自主调节功能，并评估衰老的影响。方法。分别采用AR谱分析和序贯法，获取两组受试者仰卧位和直立位时短期心率变异性（HRV）、收缩压变异性（SBPV）及压力反射敏感性（BRS）的频谱指标。结果。中年受试者仰卧位和直立位的HRV频谱指标以及仰卧位的BRS均低于青年受试者（P<0.05或P<0.01）。从中年受试者仰卧位到直立位，HRV频谱的总功率（TP）、低频功率（LF）和高频功率（HF）无显著变化，而青年受试者有典型变化。两组受试者仰卧位和直立位的SBPV频谱指标无显著差异。然而，SBPV的HF是个例外，中年受试者仰卧位时低于青年受试者（P<0.01）。对于青年受试者，仰卧位时BRS分别与HRV的LF和HF相关，且仰卧位HRV的频谱指标也与其直立位相应指标相关。中年受试者不存在这些相关性。结论。中年时，HRV和BRS均降低，且HRV指标与BRS之间不存在相关性。然而，短期血压变异性似乎与年龄无关。这表明可能存在不同的调节机制，且在静息状态下，从HRV到SBPV前馈调节可能并不重要。
