HypovolemiaHypotensionHypotension, OrthostaticHypotension, ControlledIntracranial HypotensionBlood VolumeLower Body Negative PressureShockPlasma VolumeBlood PressureFluid TherapyBlood Volume DeterminationHemodynamicsIsotonic SolutionsPlasma SubstitutesShock, HemorrhagicFluid ShiftsDehydrationVascular CapacitanceDiureticsHeart RateFurosemideHemorrhageHemodilutionBed RestThirstHead-Down TiltCardiac OutputHypernatremiaInappropriate ADH SyndromeSupine PositionCardiovascular SystemPostureBaroreflexVascular ResistanceHydroxyethyl Starch DerivativesResuscitationDrinkingHyponatremiaHematocritVasopressinsWater-Electrolyte BalanceStroke VolumePost-Exercise HypotensionSpectroscopy, Near-InfraredTrimethaphanSympathetic Nervous SystemArginine VasopressinBradycardia