title: [Effects of repeated body position change training for human orthostatic tolerance].
abstract: OBJECTIVE
  To verify the validity that repeated position change training can increase human orthostatic tolerance and to explore its mechanism.
  
  
  METHODS
  Six subjects were trained with repeated position change for 11 d according to a protocol of alternative head-down and head-up tilts, each set of training lasted for about 35 min. Their orthostatic tolerances were determined before and after training.
  
  
  RESULTS
  Compared with the data before training, subjects' symptom scores during orthostatic tolerance test after training decreased significantly (4.50 +/- 1.05 vs. 2.83 +/- 1.60, P<0.05), magnitude of the increased heart rate increase lowered significantly [(29.3 +/- 4.3) bpm vs. (13.5 +/- 7.5) bpm, P<0.01], magnitude of mean arterial blood pressure augmentation increased significantly [(4.8 +/- 4.4) mmHg vs. (9.0 +/- 3.0) mmHg, P<0.05] and cardiovascular response index decreased significantly (34.42 +/- 5.00 vs. 22.33 +/- 8.27, P<0.01). In brief, the responses to orthostatic stress were improved after training.
  
  
  CONCLUSIONS
  Repeated alternative body position change training can increase human orthostatic tolerance. This kind of training is promising for pilot, especially astronaut training.
authors.affiliation: Institute of Space Medico-Engineering, Beijing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.forename: Guang-xing
authors.initials: GX
authors.lastname: You
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Xing-hua
authors.initials: XH
authors.lastname: Liu
authors.forename: Yue-ying
authors.initials: YY
authors.lastname: Xue
authors.forename: Shuang-ning
authors.initials: SN
authors.lastname: Su
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000337:Aerospace Medicine; D001794:Blood Pressure / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D018475:Head-Down Tilt; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007024:Hypotension, Orthostatic / Q000503:physiopathology* / Q000517:prevention & control*; D011187:Posture / Q000502:physiology*; D018544:Weightlessness Countermeasures