摘要目的：观察“蛟龙号”潜航员水下作业时自主神经系统（autonomic nervous system，ANS）的交感－副交感反应，探讨潜航活动中交感－迷走神经对潜航员心脏功能的互动调控作用。方法6名潜航员驾驶“蛟龙号”载人潜水器模拟水下作业，分别记录潜航前、潜航1．5 h 和潜航2．5 h 的心电图（electrocardiogram，ECG），运用频谱分析法对其心率变异性（heart rate variability，HRV）各指标进行定量分析，包括低频（low frequency，LF）、高频（high frequency，HF）、总功率（total power，TP）、低频／高频比值（LF ／HF）以及高频／总功率比值（HF ／TP）。结果潜航前 LF 值为（2950±248）ms2，潜航1．5 h LF 升高到（3633±232）ms2，差异有统计学意义（P ＜0．05）；潜航2．5 h LF 下降到（2800±184）ms2，与潜航1．5 h 相比差异有统计学意义（P ＜0．05），但与潜航前的对照值相比差异无统计学意义（P ＜0．05）。潜航前的 HF值是（1700±107）ms2，潜航1．5 h 后下降到（1200±156）ms2，差异有统计学意义（P ＜0．05），潜航2．5 h 升高至（1917±15）ms2，比潜航1．5 h 差异有统计学意义（P ＜0．05），但与潜航前比较差异无统计学意义（P ＞0．05）；潜航前 LF／HF 值是1．73±0．81，潜航1．5 h 升高为3．02±1．11，差异有统计学意义（P ＜0．05），潜航2．5 h降为1．46±0．82，与1．5 h 比显著降低，差异有统计学意义（P ＜0．05），但与潜航前比差异无统计学意义（P ＞0．05）。潜航前 HF／TP 值是0．36±0．22，潜航1．5 h 下降为0．25±0．23，差异有统计学意义（P ＜0．05），潜航2．5 h 升高至0．76±0．11，比潜航1．5 h 显著升高，差异有统计学意义（P ＜0．05）。潜航前 TP 值是（4650±280）ms2，潜航1．5 h无明显变化，潜航2．5 h 比潜航1．5 h 和潜航前都有显著下降（P ＜0．05）。结论潜航员在水下潜航1．5 h 时交感神经活性显著升高，迷走神经的活性降低，这可能与潜水器布放下水和起航时的操作难度较大、劳动强度较高、精神较为紧张及应激反应有关；潜航2．5 h 时发生相反的变化，则可能与潜航员对舱内和海下环境逐渐适应、应激反应的逐步缓解及工作强度逐渐稳定等因素有关。

abstractsObjective To observe the effects of submerged operation on the sympathetic nerve and vagus&nbsp;nerve of the autonomic nervous system (ANS)in "Jiaolong"oceanauts and also to explore the regulation of human cardiovascular function during submerged operation.Methods Six oceanauts underwent simulated submerged operation in "Jiaolong".Electrocardiogram (ECG)was detected before submerged operation,at hour 1.5 and 2.5 respectively.Quantitative analyses were made on various indicators of heart rate variability (HRV),including low-frequency (LF),high-frequency (HF),total power (TP),LF /HF ratio and HF /TP ratio by using frequency spectral method.Results LF control value before submerged operation was (2 950 ±248)ms2 .The LF value at hour 1.5 during submerged operation increased to(3 633 ±232)ms2 ,and statistical significance could be noted when comparisons were made between them(P <0.05).The LF value at hour 2.5 during submerged operation decreased to(2 800 ±184)ms2 .Statistical significance could be noticed when it was compared with that at hour 1.5(P <0.05),however,no statistical significance could be found when it was compared with the control value before submerged operation(P <0.05).The control value of HF before submerged operation was(1 700 ±107) ms2 ,the HFvalue decreased to (1 200 ±156 )ms2 at hour 1.5 after submerged operation,and statistical significance could be noted when comparisons were made between them(P <0.05).The HFvalue increased to (1 917 ±15)ms2 at hour 2.5 after submerged operation,and statistical significance could be seen when it was compared with that at hour 1.5 (P <0.05 ).However,no statistical significance could be found when it was compared with the value before submerged operation(P <0.05).And no statistical significance could be seen when it was compared with the control value(P <0.05).The LF /HF ratio detected before submerged operation was 1.73 ±0.81,but its value at hour 1.5 after submerged operation increased to a significant value of 3.02 ± 1.11,with statistical significance(P <0.05).However,its value at hour 2.5 after submerged operation decreased to 1.46 ±0.82,and statistical significance could be noted,when it was compared with that at hour 1.5 (P <0.05).The HF /TP ratio detected before submersion was 0.36 ±0.22,but it decreased to a value of 0.25 ±0.23 at hour 1.5 after submerged operation,with statistical significance (P <0.05 ).However,at hour 2.5 after submerged operation,its value increased to 0.76 ±0.11,which was significantly higher than that detected at hour 1.5,also with statistical significance(P <0.05).The TP value detected before submerged operation was(4 650 ± 280)ms2 ,no changes could be detected at hour 1.5 after submersion.As could be seen,the TP value detected at hour 2.5 after submersion was significantly lower than the control value and that detected at hour 1.5 after submersion(P <0.05).Conclusions The sympathetic nerve activity increased,while the parasympathetic activity decreased at hour 1.5 after submersion,which might be associated with the difficult and complicated manipulation of the submersible,intensive work load,mental strain and stress reactions of the oceanauts.The reversal changes displayed at hour 2.5 after submersion might be correlated with the following factors,gradual adaption to the cabin and subsea environment,alleviation of stress reactions and decreased work load.