Variations of Time Irreversibility of Heart Rate Variability Under Normobaric Hypoxic Exposure

• DOI: 10.3389/fphys.2021.607356
• Publication Date: 2021-03-05T06:52:46Z
• Authors: Yang Li; Jianqing Li; Jian Liu; Yong Xue; Zhengtao Cao; Chengyu Liu
• Keywords: Hypoxia; RR interval; Normal Sinus Rhythm

In the field of biomedicine, time irreversibility is used to describe how imbalanced and asymmetric biological signals are. As an important feature signals, direction always ignored. To find out variation regularity heart rate variability (HRV) in initial stage hypoxic exposure, present study implemented 2 h acute normobaric exposure on six young subjects who have no plateau or hypoxia experiences; oxygen concentration was set as 12.9%. Electrocardiogram (ECG) were recorded whole process RR interval sequences extracted. Mathematical operations executed transform difference adjacent intervals into proportion distance with delay conduct analysis HRV. The same calculating method items randomly picked from MIT-BIH normal sinus rhythm database a control group. Results show that HRV environment different normoxic environment, indices group decreases continually at 1 2, curves gradually tend be steady gather each other 3 4. shows consistent tendency matter what range 1–4. Our indicates short-time goes by, regulation cardiovascular autonomic nervous system weakens; times intensity sympathetic parasympathetic nerves equal.