Effects of acute exposure to simulated altitude on heart rate variability during exercise.
Effects of acute exposure to simulated altitude on heart rate variability during exercise.
复制标题
急性暴露于模拟海拔对运动期间心率变异性的影响。
DOI：
10.1249/00005768-199405001-00921
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发表时间：
1994
影响因子：
3.3
通讯作者：
Mitsumasa Miyashita
中科院分区：
文献类型：
--
作者：
Y. Yamamoto;Y. Hoshikawa;Mitsumasa Miyashita
研究表明，人类心跳间隔的波动[心率变异性（HRV）]反映了心脏自主神经系统活动的变化。本研究旨在调查急性暴露于中等水平的模拟海拔以及由此产生的缺氧是否会改变运动期间的 HRV。七名健康男性以直立坐姿完成了一项静息测量，并完成了两次次最大稳态自行车测功机锻炼，强度相当于其估计最大工作率的 25% 和 50%。在暴露于该海拔高度 2 小时内，以随机顺序在相当于 500、1,500、2,500 和 3,500 m 的海拔高度进行实验。在测试过程中连续测量逐次心率变异性 (HRV)。 HRV 数据通过“粗粒度频谱分析”（Y. Yamamoto 和 R.L. Hughson，Physica 68D：250-264，1993）进行分析，将其总功率 (PT) 分解为谐波和非谐波（分形）分量。谐波分量进一步分为低频（0.0～0.15Hz；PL）和高频（>0.15Hz；PH）频率分量，并分别通过PL/PH和PH/PT计算相对交感（SNS）和副交感（PNS）神经系统活动指标。分形分量用于计算频谱指数（β），以评估 HRV 的整体“不规则性”。运动强度（心率、SNS 指标和 β 值增加以及 PNS 指标降低）的影响在所有海拔高度均显着 (P < 0.05)。仅在 3,500 m 高度运动时才发现海拔效应（心率和 SNS 指标增加，PNS 指标减少）（P < 0.05）。海拔高度对β值无显着影响（P > 0.05）。这些数据表明，海拔暴露对 HRV 的急性影响被发现为 1) 在中等海拔 (> 2,500 m) 运动期间和 2) 主要是 HRV 的谐波分量。
It has been shown that fluctuation of human heartbeat intervals [heart rate variability (HRV)] reflects variations in cardiac autonomic nervous system activity. The present study was designed to investigate whether the acute exposure to moderate levels of simulated altitude and the resultant hypoxia could modify HRV during exercise. Seven healthy men completed one resting measurement in the upright sitting position and two submaximal steady-state cycle ergometer exercises at intensities equivalent to 25 and 50% of their estimated maximal work rate. Experiments were conducted in random order at altitude equivalents of 500, 1,500, 2,500, and 3,500 m within 2 h of exposure to that altitude. Beat-to-beat HRV was measured continuously during the tests. HRV data were analyzed by "coarse-graining spectral analysis" (Y. Yamamoto and R.L. Hughson, Physica 68D: 250-264, 1993) to break down their total power (PT) into harmonic and nonharmonic (fractal) components. The harmonic component was further divided into low (0.0- to 0.15-Hz; PL)- and high (> 0.15-Hz; PH)-frequency components, and the indicators of relative sympathetic (SNS) and parasympathetic (PNS) nervous system activities were calculated by PL/PH and PH/PT, respectively. The fractal component was used to calculate the spectral exponent (beta) to evaluate the overall "irregularity" of HRV. The effects of exercise intensity (increase in heart rate, SNS indicator, and beta and decrease in PNS indicator) were significant (P < 0.05) at all altitude levels. The altitude effects (increase in heart rate and SNS indicator and decrease in PNS indicator) were found only during exercise at 3,500 m (P < 0.05). There was no significant effect of altitude on beta (P > 0.05). These data indicate that acute effects of altitude exposure on HRV were found 1) during exercise at moderate altitude (> 2,500 m) and 2) mainly for the harmonic components of HRV.