Bed RestHead-Down TiltWeightlessness SimulationWeightlessness CountermeasuresRestCardiovascular DeconditioningSpace FlightBedsTreatment OutcomeWeightlessnessOutcome Assessment (Health Care)Orthostatic IntoleranceLower Body Negative PressureTime FactorsPregnancy OutcomePhysiciansMedical Staff, HospitalRetrospective StudiesBed OccupancyPhysician-Patient RelationsFollow-Up StudiesProspective StudiesExerciseEarly AmbulationSupine PositionMuscular AtrophyMuscle, SkeletalPlasma VolumeAttitude of Health PersonnelOutcome and Process Assessment (Health Care)Family PracticeGreat BritainHypotension, OrthostaticRisk FactorsHypovolemiaPrognosisImmobilizationVascular CapacitanceEnglandPatient SatisfactionAmino Acids, EssentialClinical CompetenceSpinal PuncturePhysician Impairment