title: Effects of individualized centrifugation training on orthostatic tolerance in men and women.
abstract: OBJECTIVE
  Exposure to artificial gravity (AG) at different G loads and durations on human centrifuges has been shown to improve orthostatic tolerance in men. However, the effects on women and of an individual-specific AG training protocol on tolerance are not known.
  
  
  METHODS
  We examined the effects of 90 minutes of AG vs. 90 minutes of supine rest on the orthostatic tolerance limit (OTL), using head up tilt and lower body negative pressure until presyncope of 7 men and 5 women. Subjects were placed in the centrifuge nacelle while instrumented and after one-hour they underwent either: 1) AG exposure (90 minutes) in supine position [protocol 1, artificial gravity exposure], or 2) lay supine on the centrifuge for 90 minutes in supine position without AG exposure [protocol 2, control]. The AG training protocol was individualized, by first determining each subject's maximum tolerable G load, and then exposing them to 45 minutes of ramp training at sub-presyncopal levels.
  
  
  RESULTS
  Both sexes had improved OTL (14 minutes vs 11 minutes, p < 0.0019) following AG exposure. When cardiovascular (CV) variables at presyncope in the control test were compared with the CV variables at the same tilt-test time (isotime) during post-centrifuge, higher blood pressure, stroke volume and cardiac output and similar heart rates and peripheral resistance were found post-centrifuge.
  
  
  CONCLUSIONS
  These data suggest a better-maintained central circulating blood volume post-centrifugation across gender and provide an integrated insight into mechanisms of blood pressure regulation and the possible implementation of in-flight AG countermeasure profiles during spaceflights.
authors.affiliation: Medical University of Graz, Institute for Physiology, Graz, Austria.
authors.forename: Nandu
authors.initials: N
authors.lastname: Goswami
authors.affiliation: University of Kentucky, Lexington, United States of America.
authors.forename: Joyce
authors.initials: J
authors.lastname: Evans
authors.affiliation: German Sports University, Cologne, Germany; Faculty of Science, Health Education and Engineering, University of Sunshine Coast, Marrochydore, Queensland, Australia.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schneider
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: von der Wiesche
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: Edwin
authors.initials: E
authors.lastname: Mulder
authors.affiliation: Medical University of Graz, Institute for Physiology, Graz, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Rössler
authors.affiliation: Medical University of Graz, Institute for Physiology, Graz, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Hinghofer-Szalkay
authors.affiliation: Simon Fraser University, Burnaby, Canada.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Blaber
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output; D018592:Cross-Over Studies; D005260:Female; D018470:Gravity, Altered / Q000009:adverse effects*; D006801:Humans; D008297:Male; D054971:Orthostatic Intolerance / Q000503:physiopathology* / Q000517:prevention & control*; D057285:Precision Medicine; D011897:Random Allocation; D013318:Stroke Volume / Q000502:physiology; D016683:Supine Position; D055815:Young Adult