Lee C, Katsuura T, Harada H, Kikuchi Y
Dept. of Ergonomics, Graduate School of Science and Technology, Chiba University.
Ann Physiol Anthropol. 1994 Sep;13(5):233-43. doi: 10.2114/ahs1983.13.233.
The purpose of the present study was to evaluate cardiac sympathetic (SNS) and parasympathic (PNS) nervous system activities during isometric continuous and intermittent handgrip with power spectrum analysis of heart rate variability (HRV). Eight healthy men performed work at 10% maximum voluntary contraction. The sequence of tests included three different work patterns: 1) the continuous handgrip for 30 min, 2) the intermittent handgrip (10 sec contraction +5 sec relaxation) for 45 min, 3) the intermittent handgrip (10 sec contraction +10 sec relaxation) for 60 min. These experiments were performed at two different heat loads (25 degrees C and 40 degrees C, R.H. 50%). To evaluate HRV, low frequency component (0.03-0.15Hz: LFP) and high frequency component (0.15-0.5Hz: HFP) power were calculated. The SNS and PNS activities were evaluated by LFP/HFP and HFP/(HFP + LFP), respectively. Summary of the results was shown below. 1) The change of the SNS and PNS activities were not significant among the different work patterns, due to the lower work load in the present experiment. 2) The increase of HR at 25 degrees C was mediated primarily by the decrease of the PNS activities during the work periods. 3) The effects of heat loads on the SNS and PNS activities were significant. Briefly, at the same work pattern, the SNS activities at 40 degrees were higher than those at 25 degrees C, but the PNS activities at 40 degrees C were lower than those at 25 degrees C.
本研究的目的是通过心率变异性（HRV）功率谱分析，评估等长持续和间歇性握力过程中心脏交感神经（SNS）和副交感神经（PNS）的活动。八名健康男性以最大自主收缩力的10%进行工作。测试顺序包括三种不同的工作模式：1）持续握力30分钟；2）间歇性握力（10秒收缩+5秒放松）45分钟；3）间歇性握力（10秒收缩+10秒放松）60分钟。这些实验在两种不同的热负荷（25摄氏度和40摄氏度，相对湿度50%）下进行。为了评估HRV，计算了低频成分（0.03 - 0.15Hz：LFP）和高频成分（0.15 - 0.5Hz：HFP）的功率。分别通过LFP/HFP和HFP/（HFP + LFP）评估SNS和PNS的活动。结果总结如下：1）由于本实验工作负荷较低，不同工作模式下SNS和PNS活动的变化不显著。2）25摄氏度时心率升高主要是由于工作期间PNS活动的降低。3）热负荷对SNS和PNS活动的影响显著。简而言之，在相同工作模式下，40摄氏度时的SNS活动高于25摄氏度时的，但40摄氏度时的PNS活动低于25摄氏度时的。
