Relationship between autonomic nervous system function and acute mountain sickness

• Published in: Journal of Medical Colleges of PLA 2008, Vol.23 (5), p.276-282
• Main Authors: Min, Long, Lan, Huang, Kaixin, Tian, Shiyong, Yu, Yang, Yu, Jun, Qin
• Format: Article
• Language: English
• Subjects: Acute mountain sickness; Autonomic nervous system; Cold pressor test; Heart rate variability; High altitude; 心律不稳定性; 急性高山病; 自主神经系统; 高海拔
• ISSN: 1000-1948
• DOI: 10.1016/S1000-1948(08)60054-4

Objective： To elucidate the role of the autonomic nervous system （ANS） in acute mountain sickness （AMS） during the initial phase at acute high-altitude exposure. Methods： Ninety-nine healthy sea-level residents rapidly ascended to Tibet plateau （3 675 m altitude） by airplane from Chengdu plain （560 m altitude）. ANS function was tested in plain and day 2-4 in Tibet by heart rate variability （HRV）, cold pressor test （CPT）. AMS was evaluated by clinic symptomatic scores. All subjects were divided into non-AMS group （57, scores≤4） and AMS group （42, scores〉4）. Results： Compared with non-AMS group, AMS group had higher standard deviation of normal to normal intervals （SDNN）, root mean square of delta RR （rMSSD）, low-frequency （LF） power, and normalized low-frequency （LFnu） power in plain （P〈0.05）. After arrival at 3 675 m altitude, AMS group had greater reduction in percentage of delta RR〉50 ms（PNN50）, rMSSD （P〈0.01） and SDNN, LF, total power （TP） （P〈0.05）. Although no significant differences in the increase of SP and DP during CPT were found between 2 groups in plain, the SP increase during CPT of AMS group was less than non-AMS group （P〈0.05） at 3 675 m altitude. AMS symptomatic scores was not only positively correlated with SDNN, rMSSD, LF/HF in plain （P〈0.05）, but also negatively correlated with HFnu in plain （P〈0.05）. Conclusion： During the initial high altitude exposure, ANS modulation is generally blunted, but the relatively predominant sympathetic control is enhanced, and this characteristic change of ANS function is positively correlated with the development of AMS.