Supine PositionProne PositionPosturePatient PositioningTilt-Table TestHead-Down TiltGravitationHypotension, OrthostaticHeart RateSupinationBlood PressureDizzinessNephrostomy, PercutaneousRespiratory MechanicsSyncopeSyncope, VasovagalAutonomic Nervous SystemBaroreflexValsalva ManeuverHemodynamicsMovementRespirationCardiac OutputLegPressurePulmonary Gas ExchangeIndoraminEsophagusEsophageal pH MonitoringFaceTidal VolumeReference ValuesPalate, SoftHeadRestPulmonary CirculationBlood VolumeOxygenExpiratory Reserve VolumeRegional Blood FlowExercise TestTime FactorsBlood Flow VelocitySudden Infant DeathBiomechanical PhenomenaFluid ShiftsTongueExercisePlethysmographyLung Volume MeasurementsAutonomic Nervous System DiseasesVascular ResistanceTechnetium Tc 99m Aggregated AlbuminOrientationElectrocardiographyVenous PressureSympathetic Nervous SystemPhysical ExertionLungSleepCarbon DioxideRotationThoracic WallSpineVeinsSleep ParalysisFunctional Residual CapacityGastroesophageal RefluxOropharynxInhalationRibsDiaphragmThoraxPharynxBedsVentilators, Negative-PressureAirway ResistanceGravity SensingNeckCentral Venous PressurePostural BalanceReproducibility of ResultsProspective StudiesPneumoperitoneum, ArtificialAdaptation, PhysiologicalReninLymphatic IrradiationEsophageal Motility DisordersPelvisMolecular Sequence DataAirway ObstructionPerceptual DistortionPulmonary VentilationRespiratory MusclesPostural Orthostatic Tachycardia SyndromeSpace FlightManometryAnalysis of VarianceTotal Lung CapacityStroke Volume