Search results for "orthostatic tolerance"

showing 3 items of 3 documents

Breathing 100% oxygen during water immersion improves postimmersion cardiovascular responses to orthostatic stress

2016

Abstract Physiological compensation to postural stress is weakened after long‐duration water immersion (WI), thus predisposing individuals to orthostatic intolerance. This study was conducted to compare hemodynamic responses to postural stress following exposure to WI alone (Air WI), hyperbaric oxygen alone in a hyperbaric chamber (O 2 HC), and WI combined with hyperbaric oxygen (O 2 WI), all at a depth of 1.35 ATA, and to determine whether hyperbaric oxygen is protective of orthostatic tolerance. Thirty‐two healthy men underwent up to 15 min of 70° head‐up tilt (HUT) testing before and after a single 6‐h resting exposure to Air WI ( N = 10), O 2 HC ( N = 12), or O 2 WI ( N = 10). Heart …

AdultMalemedicine.medical_specialtyCardiac outputPhysiologyDivingOrthostatic intoleranceHemodynamicsBlood PressureNeurological Conditions Disorders and Treatments03 medical and health sciencesOrthostatic vital signs0302 clinical medicinePhysiology (medical)Internal medicineHeart rateImmersionMedicineAutonomic nervous systemblood flowHumansOriginal ResearchPresyncopeRespiratory Conditions Disorder and DiseasesHyperbaric Oxygenationbusiness.industryRespirationheart rate variabilityHeartStroke Volume030229 sport sciencesmedicine.diseaseSurgeryOxygenmedicine.anatomical_structureBlood pressureAutonomic nervous system; Blood flow; Blood pressure; Heart rate variability; Hyperoxia; Orthostatic tolerance; Water immersion; Adult; Diving; Humans; Hyperbaric Oxygenation; Immersion; Male; Orthostatic Intolerance; Oxygen; Vascular Resistance; Blood Pressure; Respiration; Stroke Volume; Physiology; Physiology (medical)Settore ING-INF/06 - Bioingegneria Elettronica E InformaticaVascular resistanceCardiologyOrthostatic Intolerancehyperoxiawater immersionorthostatic toleranceVascular Resistancebusiness030217 neurology & neurosurgeryHumanPhysiological Reports

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Cardiovascular and autonomic responses to physiological stressors before and after six hours of water immersion

2013

The physiological responses to water immersion (WI) are known; however, the responses to stress following WI are poorly characterized. Ten healthy men were exposed to three physiological stressors before and after a 6-h resting WI (32–33°C): 1) a 2-min cold pressor test, 2) a static handgrip test to fatigue at 40% of maximum strength followed by postexercise muscle ischemia in the exercising forearm, and 3) a 15-min 70° head-up-tilt (HUT) test. Heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), cardiac output (Q̇), limb blood flow (BF), stroke volume (SV), systemic and calf or forearm vascular resistance (SVR and CVR or FVR), baroreflex sensitivity (BRS), and HR variabili…

AdultMalemedicine.medical_specialtyPhysiologyBlood PressureStatic exerciseCardiovascular SystemCold pressorWater immersionHeart RateStress PhysiologicalTilt-Table TestInternal medicinePhysiology (medical)ImmersionMedicineHeart rate variabilityHumansAutonomic nervous systemCardiac OutputStatic ExerciseHeart rate variabilityHand Strengthbusiness.industryStressorCold pressor testHemodynamicsWaterStroke VolumeBaroreflexPhysiological responsesAutonomic nervous systemForearmEndocrinologyWater immersionRegional Blood FlowSettore ING-INF/06 - Bioingegneria Elettronica E InformaticaVascular Resistancebusinesscirculatory and respiratory physiologyOrthostatic tolerance

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Measuring postural-related changes of spontaneous baroreflex sensitivity after repeated long-duration diving: Frequency domain approaches

2012

Sustained water immersion is thought to modulate orthostatic tolerance to an extent dependent on the duration and repetition over consecutive days of the diving sessions. We tested this hypothesis investigating in ten healthy subjects the potential changes in the cardiovascular response to head-up tilt induced by single and multiple resting air dives. Parametric cross-spectral analysis of spontaneous RR interval and systolic arterial pressure variability was performed in three experimental sessions: before diving (BD), after single 6-hour dive (ASD), and after multiple 6-hour dives (AMD, 5 consecutive days with 18-hour surface interval). From this analysis, baroreflex sensitivity (BRS) was …

AdultMalemedicine.medical_specialtySupine positionDivingPostureRR intervalOrthostatic intoleranceBaroreflexSensitivity and SpecificityEndocrine and Autonomic SystemCellular and Molecular NeuroscienceOrthostatic vital signsInternal medicinemedicineHumansShort durationAnalysis of VarianceElectronic Data ProcessingEndocrine and Autonomic Systemsbusiness.industrySpectrum AnalysisHead-up tiltBaroreflexCardiovascular variabilitymedicine.diseaseCausal coherenceParametric cross-spectral analysiFrequency domainSettore ING-INF/06 - Bioingegneria Elettronica E InformaticaPower ratioCardiologyNeurology (clinical)businessOrthostatic toleranceAutonomic Neuroscience

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