Endogenous circadian rhythm in human motor activity uncoupled from circadian influences on cardiac dynamics
Endogenous circadian rhythm in human motor activity uncoupled from circadian influences on cardiac dynamics
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DOI：
10.1073/pnas.0709957104
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发表时间：
2007-12-26
影响因子：
11.1
通讯作者：
Stanley, H. Eugene
中科院分区：
文献类型：
--
作者：
Ivanov, Plamen Ch.;Hu, Kun;Stanley, H. Eugene
内源性昼夜节律起搏器影响关键的生理功能，如体温和心率，通常与睡眠/清醒周期同步。流行病学研究表明，心血管不良事件有24小时的模式，高峰出现在上午10点左右。目前尚不清楚心脏风险的这种模式是否由昼夜行为模式引起，包括活动水平和/或内部昼夜起搏器的影响。我们最近发现，心脏易损性的标度指数在昼夜节律阶段有一个内源性昼夜节律峰值，对应于大约上午10点，可以想见，这可能有助于心脏风险的早高峰。在这里，我们测试这种内源性昼夜节律对心脏动力学的影响是由昼夜节律调节的运动活动变化引起的，还是活动和心率动力学在昼夜节律周期中是分离的。我们分析了年轻健康受试者在两种互补方案期间的高频运动记录，这两种方案将睡眠/醒来周期与昼夜周期分离，同时控制预定的行为。我们发现静态活动特性(平均值和标准差)表现出明显的昼夜节律，在昼夜相对应的5-9点达到峰值。(大约比心跳波动的标度不变指数的峰值晚9h)。相比之下，活动波动的时间尺度不变组织(长期相关性)的动态特征并不表现出昼夜节律。这些发现表明，在心跳波动的尺度不变结构中，内源性昼夜节律调节的活动变化不是内源性昼夜节律的原因，也可能不会导致上午10点左右心脏风险的增加。
The endogenous circadian pacemaker influences key physiologic functions, such as body temperature and heart rate, and is normally synchronized with the sleep/wake cycle. Epidemiological studies demonstrate a 24-h pattern in adverse cardiovascular events with a peak at approximate to 10 a.m. It is unknown whether this pattern in cardiac risk is caused by a day/night pattern of behaviors, including activity level and/or influences from the internal circadian pacemaker. We recently found that a scaling index of cardiac vulnerability has an endogenous circadian peak at the circadian phase corresponding to approximate to 10 a.m., which conceivably could contribute to the morning peak in cardiac risk. Here, we test whether this endogenous circadian influence on cardiac dynamics is caused by circadian-mediated changes in motor activity or whether activity and heart rate dynamics are decoupled across the circadian cycle. We analyze high-frequency recordings of motion from young healthy subjects during two complementary protocols that decouple the sleep/wake cycle from the circadian cycle while controlling scheduled behaviors. We find that static activity properties (mean and standard deviation) exhibit significant circadian rhythms with a peak at the circadian phase corresponding to 5-9 p.m. (approximate to 9 h later than the peak in the scale-invariant index of heartbeat fluctuations). In contrast, dynamic characteristics of the temporal scale-invariant organization of activity fluctuations (long-range correlations) do not exhibit a circadian rhythm. These findings suggest that endogenous circadian-mediated activity variations are not responsible for the endogenous circadian rhythm in the scale-invariant structure of heartbeat fluctuations and likely do not contribute to the increase in cardiac risk at approximate to 10 a.m.