模拟高海拔氦氧潜水对潜水员心率变异性的影响

Effects of simulated high altitude heliox diving on heart rate variability

目的观察模拟高海拔缺氧和潜水条件下自主神经的交感一副交感的反应，探讨高海拔缺氧和潜水活动中自主神经系统的交感一迷走神经对心脏功能的互动调控作用。方法4名潜水员作为受试者在高、低压舱内分别暴露于模拟海拔3000、4000和5200m，各逗留2d，在此期间摸拟30m和50m氦氧潜水60min。记录受试者在高海拔暴露和模拟潜水时的心电图，运用频谱分析法对其总功率（TP）、高频（HF）、低频（LF）和低频／高频（LF／HF）的比值等指标进行分析。结果人体暴露于海拔高度3000、4000和5200m时，心率变异性（HRV）的TP、HF、LF，HF／（LF／HF）比海平面值明显减少，LF／HF则明显升高。与高海拔相比，在模拟30和50m潜水时发生明显相反的变化，HRV的各参数出现由高海拔暴露值向平原对照值回归转化的现象。结论高海拔暴露引起交感神经活性升高，副交感神经活性降低，在潜水时发生相反的变化，HRV有向海平面值回归转移的趋势。

Objective To observe the effects of simulated high altitude diving and hypoxia on sympathetic and parasympathetic nerves, and also to explore the effects of hypoxia and simulated diving operations on interactive regulation of the cardiac function by sympathetic and parasympathetic nerves. Methods Four divers as experimental subjects were habitated in the hyperbaric and hypobaric chambers at simulated high altitudes of 3000, 4000 and 5200 m for 2 days, during which simulated 30 m and 50 m heliox dives were conducted for a duration of 60 min. Electrocardiograms （ECG） of the subjects were monitored during high altitude exposure and the simulated dive. Analyses of such data as total power （TP）, high frequency, low frequency and ratio of high frequency and low frequency were made by using frequency spectrum method. Results The levels of TP of heart rate variability, low and high frequencies measured at 3000, 4000 and 5200 m decreased significantly, when compared with those measured at sea level. Reverse changes in th~ above data could obviously be detected in divers during simulated dives at 30 and 50 m, when compared with those detected during simple high altitude exposure. Various data of HRV had a tendency of returning from the lower levels at high altitudes to the higher levels at the sea level. Conclusions High altitude exposure could increase the sympathetic activity and in the meantime decrease the parasympathetic activity of the divers. However, during diving exposure, these data seemed to have a reversal change. HRV had a tendency of returning to the lower sea levels.