Piccirillo G, Fimognari F L, Viola E, Marigliano V
Cattedra di Geriatria, Universita di Roma La Sapienza, Italy.
Int J Cardiol. 1995 Jun 30;50(2):117-24. doi: 10.1016/0167-5273(95)93680-q.
Aging leads to a decline in autonomic nervous system function. In this study, designed to assess the influence of age on neuroautonomic regulation of cardiac activity, heart rate variability was measured by power spectral analysis and normal ranges were determined in a population of healthy subjects.
In 83 healthy volunteers (42 men and 41 women; age range 25-85 years) autonomic nervous system function was assessed by autoregressive spectral analysis of heart rate variability in clinostatism and after passive orthostatic load (head-up tilt). The analysis considered two spectral components relevant to the study of the autonomic nervous system--high-frequency power (approximately 0.05 Hz) and low-frequency power (approximately 0.10 Hz)--and the ratio between them. Low-frequency spectral components, in particular the ratio between low- and high-frequency spectra, reflect sympathetic activity; high-frequency components reflect parasympathetic activity.
For data comparison, the study group was subdivided into three age groups: 25 subjects (12 men and 13 women) under 44 years of age; 28 (15 men and 13 women) aged 44-64 years; and 30 (15 men and 15 women) over 64 years of age. The natural logarithms and normalized units of low- and high-frequency power, and the low-to-high power ratio were used to calculate 95% confidence intervals. Power spectral analysis at baseline and after postural tilt showed significantly higher low-frequency power of heart rate variability (P < 0.05), natural logarithm of power (P < 0.001) and normalized units (P < 0.001) in the two younger groups than in the oldest group. The two younger age-groups also had significantly increased high-frequency power (P < 0.05) and natural logarithm of power (P < 0.05). The oldest age group had significantly increased high-frequency power analyzed in normalized units (P < 0.001).
The age-related lowering observed in nearly all the spectral frequency components of heart rate variability confirms in healthy subjects that autonomic nervous system function declines with age.
衰老会导致自主神经系统功能下降。在本研究中，旨在评估年龄对心脏活动神经自主调节的影响，通过功率谱分析测量心率变异性，并在健康受试者群体中确定正常范围。
对83名健康志愿者（42名男性和41名女性；年龄范围25 - 85岁）进行研究，通过对静息状态和被动直立负荷（头高位倾斜）后心率变异性的自回归谱分析来评估自主神经系统功能。该分析考虑了与自主神经系统研究相关的两个频谱成分——高频功率（约0.05Hz）和低频功率（约0.10Hz）——以及它们之间的比值。低频频谱成分，特别是低频与高频频谱的比值，反映交感神经活动；高频成分反映副交感神经活动。
为了进行数据比较，研究组被分为三个年龄组：44岁以下的25名受试者（12名男性和13名女性）；44 - 64岁的28名（15名男性和13名女性）；64岁以上的30名（15名男性和15名女性）。使用低频和高频功率的自然对数及标准化单位，以及低功率与高功率比值来计算95%置信区间。基线和体位倾斜后的功率谱分析显示，两个较年轻组的心率变异性低频功率（P < 0.05）、功率自然对数（P < 0.001）和标准化单位（P < 0.001）显著高于最年长组。两个较年轻年龄组的高频功率（P < 0.05）和功率自然对数（P < 0.05）也显著增加。最年长组经标准化单位分析的高频功率显著增加（P < 0.001）。
在健康受试者中，心率变异性几乎所有频谱频率成分中观察到的与年龄相关的降低证实，自主神经系统功能随年龄下降。
