正加速度暴露对人体心率变异性的影响

Effect of positive acceleration exposure on heart rate variability

目的探讨正加速度暴露对心率变异性(heart rate variability,HRV)的影响。方法本研究为单臂试验。于2023年7月23-25日,招募同一训练批次、飞行时长>300 h的12名受试者在载人离心机上进行峰值为+3.5、+4.25 Gz,持续时间各10 s的过载暴露,监测并分析受试者在正加速度过载暴露中的心率、呼吸频率、短时程HRV时域及频域指标。结果12名受试者在负荷+3.5和+4.25 Gz正加速度暴露条件下:(1)心率分别为(135.42±14.78)/min和(143.92±14.47)/min,呼吸频率为(23.57±4.09)/min和(26.80±4.71)/min;较暴露前的(97.08±14.61)/min、(14.86±2.06)/min均显著增加(P<0.01)。(2)HRV时域指标“相邻窦性RR间期差值的均方根(root mean square of difference between successive normal RR intervals,RMSSD)”在+3.5、+4.25 Gz过载条件下分别为(7.69±4.32)、(6.84±3.41)ms,与暴露前[(13.14±6.37)ms]比较显著降低(P<0.05)。(3)HRV频域指标高频功率(high frequency,HF)分别为(20.53±8.80)和(16.04±7.19)ms^(2),与暴露前[(44.07±24.67)ms^(2)]比较显著降低(P<0.05);低频功率(low frequency,LF)在+3.5和+4.25 Gz过载条件下分别为(38.07±19.72)ms^(2)和(42.46±17.08)ms^(2),与暴露前的(26.33±19.10)ms^(2)比较差异无统计学意义(P>0.05);(4)+3.5和+4.25 Gz暴露时的LF/HF值分别为(4.02±1.52)、(5.32±1.86),与暴露前的(0.67±0.32)比较均显著增加(P<0.05)。结论正加速度暴露显著影响心率、呼吸频率、RMSSD、LF/HF和HF等生理指标,提示正加速度暴露导致人体交感神经张力增大,心率变异性显著增加。

Objective To investigate the effect of exposure to positive acceleration on heart rate variability(HRV).Methods A single-arm trial was conducted on 12 participants who have a flight duration of>300 h were subjected from a same training batch between July 23 and 25,2023.They were exposed to overloading with a peak value of+3.5 and+4.25 Gz for a duration of 10 s respectively on a manned centrifuge.Heart rate,respiratory rate,and time-domain and frequency-domain indicators of short-term HRV under exposure to overloaded positive acceleration were collected,recorded and analyzed.Results Under the overloaded+3.5 and+4.25 Gz positive acceleration for 10 s:①The heart rate was 135.42±14.78 and 143.92±14.47 beats/min,the respiratory rate was 23.57±4.09 and 26.80±4.71 breaths/min,respectively,and both rates were significantly higher than those before exposure(97.08±14.61 beats/min and 14.86±2.06 breaths/min,P<0.01);②The time-domain indicator,root mean square of difference between successive normal RR intervals(RMSSD),was 7.69±4.32 and 6.84±3.41 ms respectively under+3.5 and+4.25 Gz positive acceleration,and both rates were obviously lower than before exposure(13.14±6.37 ms,P<0.05);③The frequency-domain indicator,high frequency(HF)was 20.53±8.80 and 16.04±7.19 ms^(2),respectively,and both were obviously lower than those before exposure of(44.07±24.67 ms^(2),P<0.05);another frequency-domain indicator,low frequency(LF)was 38.07±19.72 and 42.46±17.08 ms^(2) respectively,but the values had no statistical difference with the value before exposure(26.33±19.10 ms^(2),P>0.05);④The LF/HF ratio of the 2 exposure doses was 4.02±1.52 and 5.32±1.86 respectively after expose,and 0.67±0.32 before exposure,and a significant increase was observed(P<0.05).Conclusion Positive acceleration exposure significantly affects heart rate,respiratory rate,and HRV time-and frequency-domain indicators RMSSD,LF/HF,and HF.Our results suggest that the exposure leads to increased tone in human sympathetic nerve and significant increment in HRV.