Casties J-F, Mottet D, Le Gallais D
Université Montpellier I, EA 2991 Efficience et Déficience Motrices, Montpellier, France.
Int J Sports Med. 2006 Oct;27(10):780-5. doi: 10.1055/s-2005-872968. Epub 2006 Feb 1.
We investigated the time course of RR interval variability during exercise and subsequent 50 minutes of recovery in seven well-trained male cyclists who performed an exercise with 3 successive 8 min stages at 40 %, 70 % and 90 % of their maximal oxygen uptake. The goal of the study was to check whether the decrease in the amplitude of heart rate variability during heavy exercise was accompanied by changes in the chaotic structure of the fluctuations. Heart rate variability was analysed in the temporal and frequency domain using traditional tools and using non-linear methods (Largest Lyapunov Exponent, Detrended Fluctuation Analysis, Minimum Embedding Dimension). When compared to rest, variability at the heaviest exercise intensity was significantly lower (RR: 0.94 +/- 0.22 vs. 0.34 +/- 0.01 ms; SDRR: 0.11 +/- 0.04 vs. 0.01 +/- 0.00 ms) due to a decrease in both LF (2101 +/- 1450 vs. 0.14 +/- 0.09 ms (2) . Hz (-1)) and HF spectral energy (1148 +/- 1126 vs. 7.88 +/- 9.24 ms (2) . Hz (-1)). Non-linear analyses showed that heart rate variability remained chaotic whatever the exercise intensity (the largest Lyapunov exponent was positive at 90 % of the maximal oxygen uptake), with a fractal organisation that tended towards white noise (DFA value close to 0.5) during heavy exercise. During recovery, temporal and spectral variables came back to their rest values within about 30 minutes following an exponential pattern. Non-linear analyses revealed that heartbeat dynamics were disorganised at the beginning of recovery, and involved more regulating systems than at rest, even after 50 minutes of recovery. We concluded that, during heavy exercise, heart rate variability was mainly influenced by other factors than autonomous nervous system, and suggest that mechanical or neurological couplings between the cardiac, locomotor and respiratory systems could play an important part in the observed changes.
我们对7名训练有素的男性自行车运动员在运动期间以及随后50分钟恢复过程中的RR间期变异性的时间进程进行了研究。这些运动员进行了一项运动，包括3个连续8分钟阶段，强度分别为其最大摄氧量的40%、70%和90%。本研究的目的是检验剧烈运动期间心率变异性幅度的降低是否伴随着波动混沌结构的变化。使用传统工具以及非线性方法（最大Lyapunov指数、去趋势波动分析、最小嵌入维数）在时域和频域分析心率变异性。与静息状态相比，在最重运动强度下变异性显著降低（RR：0.94±0.22对0.34±0.01毫秒；SDRR：0.11±0.04对0.01±0.00毫秒），这是由于低频（2101±1450对0.14±0.09毫秒²·赫兹⁻¹）和高频谱能量（1148±1126对7.88±9.24毫秒²·赫兹⁻¹）均降低。非线性分析表明，无论运动强度如何，心率变异性均保持混沌状态（在最大摄氧量的90%时最大Lyapunov指数为正），在剧烈运动期间具有趋向于白噪声的分形组织（DFA值接近0.5）。在恢复过程中，时域和频域变量在约30分钟内呈指数模式恢复到静息值。非线性分析显示，恢复开始时心跳动力学紊乱，即使在恢复50分钟后，涉及的调节系统也比静息时更多。我们得出结论，在剧烈运动期间，心率变异性主要受自主神经系统以外的其他因素影响，并表明心脏、运动和呼吸系统之间的机械或神经耦合可能在观察到的变化中起重要作用。
