Elevated heart rate variability in physically active postmenopausal women: A cardioprotective effect?
Elevated heart rate variability in physically active postmenopausal women: A cardioprotective effect?
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DOI：
10.1152/ajpheart.1996.271.2.h455
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发表时间：
1996-08-01
影响因子：
4.8
通讯作者：
Seals, DR
中科院分区：
文献类型：
--
作者：
Davy, KP;Miniclier, NL;Seals, DR
绝经后冠心病（CHD）和心源性猝死（CSD）的发病率增加，但在体力活动较少的女性中发病率较低。低心率变异性（HRV）是CHD和CSD的危险因素。本研究的目的是检验这一假设，即心率变异性在休息时是更大的体力活动相比，较少活动的绝经后妇女。如果是真的，我们进一步假设，在体力活动的女性更大的HRV将与自发性心脏压力反射敏感性（SBRS）的升高密切相关。对9名体力活动的绝经后妇女（年龄= 53 +/- 1岁）和11名年龄匹配的对照组（年龄= 56 +/- 2岁）在仰卧、坐姿和站立姿势下进行5分钟的控制频率呼吸（15次呼吸/min）期间测量HRV（时域和频域测量）和SBRS（序列法）。运动组体重、体重指数、体脂百分比较低（P < 0.01），最大摄氧量较高（P < 0.01）。在所有体位中，活动女性的R-R间期（时域测量）的标准差较高（P < 0.05），心率变异性的高频、低频和总功率也较高。SBRS在所有体位中均高于体力活动组（P < 0.05），其对HRV高频功率变异的解释率接近70%（P < 0.05）。目前的调查结果表明，体力活动的绝经后妇女表现出较高水平的心率变异性与年龄相匹配，较少活动的妇女相比。此外，SBRS占了HRV高频功率方差的大部分，这表明可能与心脏迷走神经对心率的调节存在机械联系。我们的研究结果可能提供了一个可能的心脏保护机制，在体力活动的绝经后妇女的洞察力。
Coronary heart disease (CHD) and cardiac sudden death (CSD) incidence accelerates after menopause, but the incidence is lower in physically active versus less active women. Low heart rate variability (HRV) is a risk factor for CHD and CSD. The purpose of the present investigation was to test the hypothesis that HRV at rest is greater in physically active compared with less active postmenopausal women. If true, we further hypothesized that the greater HRV in the physically active women would be closely associated with an elevated spontaneous cardiac baroreflex sensitivity (SBRS). HRV (both time and frequency domain measures) and SBRS (sequence method) were measured during 5-min periods of controlled frequency breathing (15 breaths/min) in the supine, sitting, and standing postures in 9 physically active postmenopausal women (age = 53 +/- 1 yr) and 11 age-matched controls (age = 56 +/- 2 yr). Body weight, body mass index, and body fat percentage were lower (P < 0.01) and maximal oxygen uptake was higher (P < 0.01) in the physically active group. The standard deviation of the R-R intervals (time domain measure) was higher in all postures in the active women (P < 0.05) as were the high-frequency, low-frequency, and total power of HRV. SBRS also was higher (P < 0.05) in the physically active women in all postures and accounted for similar to 70% of the variance in the high-frequency power of HRV (P < 0.05). The results of the present investigation indicate that physically active postmenopausal women demonstrate higher levels of HRV compared with age-matched, less active women. Furthermore, SBRS accounted for the majority of the variance in the high-frequency power of HRV, suggesting the possibility of a mechanistic link with cardiac vagal modulation of heart rate. Our findings may provide insight into a possible cardioprotective mechanism in physically active postmenopausal women.