title: [Cardiovascular reactions to gravitational force in different directions].
abstract: OBJECTIVE
  To observe the features of the cardiovascular reactions to gravitational forces along different axes of the body.
  
  
  METHODS
  Dogs were exposed to gravitational forces along axes of body on an animal centrifuge.
  
  
  RESULTS
  It was found that when the direction of G force changed from +Gz to +Gx, the predominating effect on the cardiovascular system changed from the drop of eye level blood pressure to the increase of central venous pressure, and the reactions of the organism changed from a presson reflex of the arterial system to the inhibition of cardiac activities at higher G levels. The turning point was found to be at the back angle of 75 degrees with respect to the direction of the gravitational force.
  
  
  CONCLUSIONS
  These findings provide an important reference for choosing the optimal seat back angle in a manned space vehicle.
authors.affiliation: Institute of Space Medico-Engineering, Beijing, China.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Xue
authors.forename: G Y
authors.initials: GY
authors.lastname: Liu
authors.forename: B S
authors.initials: BS
authors.lastname: Xie
authors.forename: X Y
authors.initials: XY
authors.lastname: Cheng
authors.forename: Y C
authors.initials: YC
authors.lastname: Wang
mesh_terms: D000054:Acceleration; D000337:Aerospace Medicine; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D002496:Central Venous Pressure / Q000502:physiology; D002498:Centrifugation; D004285:Dogs; D006112:Gravitation; D006339:Heart Rate / Q000502:physiology; D018471:Hypergravity; D011187:Posture / Q000502:physiology*; D013318:Stroke Volume / Q000502:physiology