Regulatory model for the emergence of cardiorespiratory-locomotor coupling during exercise in humans

人体运动过程中出现心肺运动耦合的调节模型

基本信息

批准号：
18500472
负责人：
NIIZEKI Kyuichi
金额：
$ 2.4万
依托单位：
Yamagata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

The objective of the present study was whether a phase synchronization between cardiac, respiratory, and locomotor rhythms relates to certain biological functions, such as minimization of the energy costs of cardiac and respiratory work. To this end, we investigated whether Vo_2, Vco_2, and ventilatory equivalents are altered with the emergence of cardiorespiratory-locomotor coupling (CRLC) during walking, as well as whether respiratory rhythm can modulate the strength of cardiolocomotor coupling. Eleven healthy subjects participated in a 20 min session of walking on a motorized treadmill. The treadmill speed was adjusted until a target heart rate of 120 beats/min. The subjects were required to walk synchronizing their locomotion pace with their mean heart rate at a ratio of 1:2, during which they controlled their respiratory rhythm either to their locomotor rhythm or to computer generated waveform of 0.5Hz. The strength of phase synchronization between cardiac and locomotor rhythms wa … More s evaluated by phase coherence. We found in all subjects that when breathing rhythm was voluntarily synchronized with locomotor rhythm, phase coherence became high (P<0.01) compared with that observed when breathing rhythm was paced constant. Spectral analysis on fluctuation of heart period revealed that the respiratory modulation of heartbeats decreased when phase coherence increased. We also found that averaged ventilatory equivalent for 0_2 tended to decrease slightly but significantly with the emergence of CRLC. We then developed a coupled oscillator model using FitzHugh-Nagumo equation that could reproduce the synchronization between two rhythms, I.e. cardiac and locomotor rhythms. We included phase dependent property of cardiac oscillator, which was assumed to exhibit phase advance during systolic phase. Results of the simulation demonstrated that synchronization occurred at just before the diastolic phase of cardiac cycle, which was comparable with the experimental data obtained. Less

本研究的目的是心脏，呼吸和运动节律之间的相位同步是否与某些生物学功能有关，例如最小化心脏和呼吸系统的能量成本。为此，我们调查了随着心脏差异偶联（CRLC）的出现，VO_2，VCO_2和通气等效物是否会发生变化，以及呼吸节奏是否可以调节心脏体温病偶联的强度。 11个健康受试者参加了20分钟的摩托车跑步机的行走。调整跑步机速度，直到目标心率为120次/分钟。要求受试者以1：2的比率与平均心率同步的运动空间同步，在此期间，他们控制了呼吸节奏与运动节奏或计算机产生的0.5Hz的波形。心律和运动节律之间的相同步强度通过相干评估。我们在所有受试者中都发现，当呼吸节奏与运动节奏自愿同步时，与当呼吸节奏的节奏为常数时相比，相位相干性变得很高（p <0.01）。心脏周期波动的光谱分析表明，当相干性增加时，心跳的呼吸调节减少。我们还发现，平均0_2招标的通风等效略微减小，但随着CRLC的出现而显着降低。然后，我们使用Fitzhugh-Nagumo方程开发了一个耦合的振荡器模型，该模型可以重现两个节奏之间的同步，即。心脏和运动节奏。我们包括了心脏振荡器的相位依赖性特性，该特性假定在收缩期存在相位。模拟的结果表明同步发生在心脏周期的舒张期之前，这与获得的实验数据相当。较少的