title: The Effects of Guided Imagery on Heart Rate Variability in Simulated Spaceflight Emergency Tasks Performers.
abstract: OBJECTIVE
  The present study aimed to investigate the effects of guided imagery training on heart rate variability in individuals while performing spaceflight emergency tasks.
  
  
  METHODS
  Twenty-one student subjects were recruited for the experiment and randomly divided into two groups: imagery group (n = 11) and control group (n = 10). The imagery group received instructor-guided imagery (session 1) and self-guided imagery training (session 2) consecutively, while the control group only received conventional training. Electrocardiograms of the subjects were recorded during their performance of nine spaceflight emergency tasks after imagery training.
  
  
  RESULTS
  In both of the sessions, the root mean square of successive differences (RMSSD), the standard deviation of all normal NN (SDNN), the proportion of NN50 divided by the total number of NNs (PNN50), the very low frequency (VLF), the low frequency (LF), the high frequency (HF), and the total power (TP) in the imagery group were significantly higher than those in the control group. Moreover, LF/HF of the subjects after instructor-guided imagery training was lower than that after self-guided imagery training.
  
  
  CONCLUSIONS
  Guided imagery was an effective regulator for HRV indices and could be a potential stress countermeasure in performing spaceflight tasks.
authors.affiliation: China Astronaut Research and Training Center, Beijing 100094, China ; National Key Laboratory of Human Factors Engineering, Beijing 100094, China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Yijing
authors.affiliation: China Astronaut Research and Training Center, Beijing 100094, China.
authors.forename: Du
authors.initials: D
authors.lastname: Xiaoping
authors.affiliation: China Astronaut Research and Training Center, Beijing 100094, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Fang
authors.affiliation: China Astronaut Research and Training Center, Beijing 100094, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Xiaolu
authors.affiliation: China Astronaut Research and Training Center, Beijing 100094, China.
authors.forename: Wu
authors.initials: W
authors.lastname: Bin
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D002681:China; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D013026:Space Flight