title: Gender differences in cardiovascular tolerance to short radius centrifugation.
abstract: In preparing for the NASA Artificial Gravity Pilot Study the planned centrifuge loading protocol was tested in 11 ambulatory subjects (6 men, 5 women). Each was subjected to a single 60 min trial with 2.5G of equivalent gravitational load feet and 1G at the level of the mediastinum. Amongst the men, 5/6 completed the trial successfully with no adverse sequelae. However, amongst the women, 4/5 tests were stopped early because of presyncope. Women are known to have a greater predisposition to syncope following orthostatic stress under normal tilt table conditions, during lower body negative pressure and following space flight. Amongst the factors which may have contributed to their lower tolerance to centrifugation are anthropometric factors, the vasoactive effects of sex hormones, catecholamine levels, ability to augment total peripheral resistance in response to orthostatic stress, and structural differences in cardiac anatomy and physiology. However, determining the true cause of this difference will require further investigation.
authors: University College London, Gower Street, London, WC1E 6BT, UK. kevinjfong@gmail.com
authors: Kevin J
authors: KJ
authors: Fong
authors: Maneesh
authors: M
authors: Arya
authors: William H
authors: WH
authors: Paloski
mesh_terms: D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D002319:Cardiovascular System / Q000503:physiopathology*; D002498:Centrifugation / Q000009:adverse effects*; D005260:Female; D018470:Gravity, Altered / Q000009:adverse effects*; D018475:Head-Down Tilt; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012107:Research Design; D012737:Sex Factors; D013026:Space Flight; D013575:Syncope / Q000209:etiology* / Q000503:physiopathology; D013997:Time Factors; D014481:United States; D018557:United States National Aeronautics and Space Administration; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation