title: Effect of postural changes on cardiovascular parameters across gender.
abstract: BACKGROUND
  We investigated the effect of postural changes on various cardiovascular parameters across gender. Twenty-eight healthy subjects (16 male, 12 female) were observed at rest (supine) and subjected to 3 interventions; head-down tilt (HDT), HDT with lower body negative pressure (HDT+ LBNP at -30 mm Hg), and head-up tilt (HUT), each for 10 minutes separated by a 10 minutes recovery period.
  
  
  METHODS
  Measurements were recorded for heart rate (HR), standard deviation of the normal-to-normal intervals, root mean square of successive differences between the normal-to-normal intervals, heart rate variability-low frequency (LFRRI), heart rate variability-high frequency (HFRRI), low frequency/high frequency ratio (LFRRI/HFRRI), systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP), total peripheral resistance index (TPRI), stroke index (SI), cardiac index (CI), index of contractility (IC), left ventricular work index, and left ventricular ejection time.
  
  
  RESULTS
  Across all cardiovascular parameters, there was a significant main effect of the intervention applied but there was no significant main effect of gender across all parameters.
  
  
  CONCLUSIONS
  The results suggest that there are no specific gender differences in regards to the measured variables under the conditions of this study. Furthermore, these results suggest that in healthy subjects, there appears to be evidence that LBNP partially elicits similar cardiovascular responses to HUT, which supports the use of LBNP as an intervention to counteract the effects of central hypovolemia.
authors.affiliation: Gravitational Physiology and Medicine Research Unit, Institute of Physiology, Medical University of Graz, Graz, Austria Kings College, London, UK Department of Neurophsiology, University of Linkoping, Sweden Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: Kieran
authors.initials: K
authors.lastname: Patel
authors.forename: Andreas
authors.initials: A
authors.lastname: Rössler
authors.forename: Helmut Karl
authors.initials: HK
authors.lastname: Lackner
authors.forename: Irhad
authors.initials: I
authors.lastname: Trozic
authors.forename: Charles
authors.initials: C
authors.lastname: Laing
authors.forename: David
authors.initials: D
authors.lastname: Lorr
authors.forename: David A
authors.initials: DA
authors.lastname: Green
authors.forename: Helmut
authors.initials: H
authors.lastname: Hinghofer-Szalkay
authors.forename: Nandu
authors.initials: N
authors.lastname: Goswami
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D005260:Female; D018475:Head-Down Tilt; D064368:Healthy Volunteers; D006334:Heart Function Tests; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D012737:Sex Factors; D014655:Vascular Resistance / Q000502:physiology*