title: Is autonomic modulation different between European and Chinese astronauts?
abstract: OBJECTIVE
  The objective was to investigate autonomic control in groups of European and Chinese astronauts and to identify similarities and differences.
  
  
  METHODS
  Beat-to-beat heart rate and finger blood pressure, brachial blood pressure, and respiratory frequency were measured from 10 astronauts (five European taking part in three different space missions and five Chinese astronauts taking part in two different space missions). Data recording was performed in the supine and standing positions at least 10 days before launch, and 1, 3, and 10 days after return. Cross-correlation analysis of heart rate and systolic pressure was used to assess cardiac baroreflex modulation. A fixed breathing protocol was performed to measure respiratory sinus arrhythmia and low-frequency power of systolic blood pressure variability.
  
  
  RESULTS
  Although baseline cardiovascular parameters before spaceflight were similar in all astronauts in the supine position, a significant increase in sympathetic activity and a decrease in vagal modulation occurred in the European astronauts when standing; spaceflight resulted in a remarkable vagal decrease in European astronauts only. Similar baseline supine and standing values for heart rate, mean arterial pressure, and respiratory frequency were shown in both groups. Standing autonomic control was based on a balance of higher vagal and sympathetic modulation in European astronauts.
  
  
  CONCLUSIONS
  Post-spaceflight orthostatic tachycardia was observed in all European astronauts, whereas post-spaceflight orthostatic tachycardia was significantly reduced in Chinese astronauts. The basis for orthostatic intolerance is not apparent; however, many possibilities can be considered and need to be further investigated, such as genetic diversities between races, astronaut selection, training, and nutrition, etc.
authors: Department of Cardiology, Beijing Friendship Hospital, China Capital Medical University, Beijing, China; Department of Cardiology, University Hospital Gasthuisberg, K. U. Leuven, Leuven, Belgium.
authors: Jiexin
authors: J
authors: Liu
authors: China Astronaut Center, Beijing, China.
authors: Yongzhi
authors: Y
authors: Li
authors: Department of Cardiology, University Hospital Gasthuisberg, K. U. Leuven, Leuven, Belgium.
authors: Bart
authors: B
authors: Verheyden
authors: China Astronaut Center, Beijing, China.
authors: Shanguang
authors: S
authors: Chen
authors: China Astronaut Center, Beijing, China.
authors: Zhanghuang
authors: Z
authors: Chen
authors: China Astronaut Center, Beijing, China.
authors: Yuqing
authors: Y
authors: Gai
authors: China Astronaut Center, Beijing, China.
authors: Jianzhong
authors: J
authors: Liu
authors: China Astronaut Center, Beijing, China.
authors: Jianyi
authors: J
authors: Gao
authors: China Astronaut Center, Beijing, China.
authors: Qiong
authors: Q
authors: Xie
authors: China Astronaut Center, Beijing, China.
authors: Ming
authors: M
authors: Yuan
authors: Department of Cardiology, Beijing Friendship Hospital, China Capital Medical University, Beijing, China.
authors: Qin
authors: Q
authors: Li
authors: Department of Cardiology, Beijing Friendship Hospital, China Capital Medical University, Beijing, China.
authors: Li
authors: L
authors: Li
authors: Department of Cardiology, University Hospital Gasthuisberg, K. U. Leuven, Leuven, Belgium.
authors: André E
authors: AE
authors: Aubert
mesh_terms: D000328:Adult; D044466:Asian People; D018480:Astronauts; D001341:Autonomic Nervous System / Q000502:physiology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D054971:Orthostatic Intolerance / Q000209:etiology / Q000503:physiopathology; D013026:Space Flight; D013610:Tachycardia / Q000209:etiology / Q000503:physiopathology; D044465:White People