title: Artificial gravity: a possible countermeasure for post-flight orthostatic intolerance.
abstract: Four payload crewmembers were exposed to sustained linear acceleration in a centrifuge during the Neurolab (STS-90) flight. In contrast to previous studies, otolith-ocular reflexes were preserved during and after flight. This raised the possibility that artificial gravity may have acted as a countermeasure to the deconditioning of otolith-ocular reflexes. None of the astronauts who were centrifuged had orthostatic intolerance when tested with head-up passive tilt after flight. Thus, centrifugation may also have helped maintain post-flight hemodynamic responses to orthostasis by preserving the gain of the otolith-sympathetic reflex. A comparison with two fellow Neurolab orbiter crewmembers not exposed to artificial gravity provided some support for this hypothesis. One of the two had hemodynamic changes in response to post-flight tilt similar to orthostatically intolerant subjects from previous missions. More data is necessary to evaluate this hypothesis, but if it were proven correct, in-flight short-radius centrifugation may help counteract orthostatic intolerance after space flight.
authors.affiliation: Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029, USA. steven.moore@mssm.edu
authors.forename: Steven T
authors.initials: ST
authors.lastname: Moore
authors.forename: André
authors.initials: A
authors.lastname: Diedrich
authors.forename: Italo
authors.initials: I
authors.lastname: Biaggioni
authors.forename: Horacio
authors.initials: H
authors.lastname: Kaufmann
authors.forename: Theodore
authors.initials: T
authors.lastname: Raphan
authors.forename: Bernard
authors.initials: B
authors.lastname: Cohen
mesh_terms: D000054:Acceleration; D018480:Astronauts; D001794:Blood Pressure / Q000502:physiology; D002498:Centrifugation; D018495:Fluid Shifts / Q000502:physiology; D018470:Gravity, Altered; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007024:Hypotension, Orthostatic / Q000517:prevention & control*; D010037:Otolithic Membrane / Q000502:physiology; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D013026:Space Flight; D014893:Weightlessness / Q000009:adverse effects*; D018544:Weightlessness Countermeasures