AnatomyDiseasesChemicals and DrugsAnalytical, Diagnostic and Therapeutic Techniques and EquipmentPsychiatry and PsychologyPhenomena and ProcessesAnthropology, Education, Sociology and Social PhenomenaTechnology, Industry, AgricultureHealth Care
Lower Body Negative PressureHypovolemiaForearmBed RestOrthostatic IntoleranceHead-Down TiltBlood PressureDizzinessHeart RateCentral Venous PressureVascular CapacitancePressoreceptorsHypotension, OrthostaticBaroreflexCardiovascular DeconditioningSympathetic Nervous SystemVascular ResistanceSupine PositionWeightlessness SimulationGravity SuitsWeightlessness CountermeasuresRegional Blood FlowSpace FlightReflexSyncopeNegative-Pressure Wound TherapyHemodynamicsPlethysmographyCardiovascular Physiological PhenomenaCardiac OutputVentilators, Negative-PressureArterial PressureVasoconstrictionTilt-Table TestBlood VolumeNorepinephrinePressureGravitationPostureLegWeightlessnessStroke VolumeBlood Flow VelocityVasomotor SystemCold TemperatureAutonomic Nervous SystemHypotensionCardiovascular SystemSkin TemperatureComplianceVeinsHand StrengthRestExercisePelvisPulmonary Wedge PressureMuscle, SkeletalBrachial ArteryStress, PhysiologicalEpinephrineMiddle Cerebral ArteryCerebrovascular CirculationTime FactorsOxygen ConsumptionReference ValuesHeartAnalysis of VarianceSkinElectrocardiographyMusclesAir PressureAgingSuctionAbdominal Wound Closure TechniquesSkin Care
MmHgBaroreceptorArterialBaroreflexStimulusVascularOrthostaticReflexesSupineAtrialPosturalAssociated with carotidHydrostatic pressureUprightSympathetic nerve activityToleranceAerobicSubjectsSedentaryHumansStiffnessIndividualsBaselinePeakControlStressMalesBACKGROUNDExerciseSyndromeIncreaseConceptDataRiskMassHighStudyActivity
MmHg4
  • Recording of the temporal relationship of repeating oscillatory pattern between arterial blood pressure (BP) and muscle sympathetic nerve activity (MSNA) obtained from a healthy human during simulated hemorrhage of an estimated 25% blood loss induced by 70 mmHg LBNP. (comprehensivephysiology.com)
  • 20 mmHg) applied at rest and simultaneously during low- (15% maximum contraction) and moderate-intensity (30% maximum contraction) rhythmic handgrip. (researchgate.net)
  • Mean arterial pressure (MAP), heart rate (HR), systemic vascular resistance index (SVRI), cardiac index (CI), and stroke volume index (SVI) were measured continuously during − 0, − 20, and − 40 mmHg LBNP. (springer.com)
  • The number of MSNA bursts per low‐frequency cycle increased from 2.55 ± 0.68 at baseline to 5.44 ± 1.56 at −40 mmHg of LBNP. (hal.science)
Baroreceptor3
  • This polymorphism was also associated with increased platelet aggregation, altered baroreceptor sensitivity, and diminished salt excretion in healthy, college-age students with no evidence of high blood pressure. (grantome.com)
  • Autonomic responses to increases and decreases in baroreceptor activity will be assessed by loading, and unloading, of the central blood volume with immersion in thermal-neutral water and graded lower body negative pressure (LBNP), respectively. (grantome.com)
  • Central hypovolemia by application of lower-body negative-pressure (LBNP) elicits baroreceptor mediated sympathetic reflexes to maintain arterial blood pressure. (indoximity.com)
Arterial6
  • Methods and Results - In a double-blind randomized study, 25 healthy subjects with a positive response to either carotid sinus massage (CSM) or lower body negative pressure (LBNP) received Paxil (20 mg/d) or placebo for 6 weeks, Arterial baroreflex sensitivity (BRS), muscle sympathetic nerve activity (SNA), baroreflex control of SNA, blood pressure, and heart rate responses to CSM and LBNP were measured at baseline and at 6 weeks. (elsevierpure.com)
  • Conclusions - Paxil decreases arterial BRS but does not prevent the presyncope associated with LBNP. (elsevierpure.com)
  • Comparisons of mean arterial blood pressures in rats (closed circles, solid lines) and humans (open circles, broken lines) during progressive lower body negative pressure (A) and controlled hemorrhage (B). (comprehensivephysiology.com)
  • Responses of heart rate (broken line) and mean arterial pressure (solid line) during graded LBNP in a single subject demonstrating the onset of severe hypotension and bradycardia with hemodynamic decompensation. (comprehensivephysiology.com)
  • Coherence, gain, and frequency of highest coherence between systolic/diastolic arterial pressure (SAP/DAP) and RR‐interval time series were also computed. (hal.science)
  • Known to be a multifaceted mechanism consisting of components of the theory of cephalad fluid shift, compartmentalization & alternative compartmentalization theories, increased intracranial pressure, differential translaminar pressure gradients, aberrancies in lymphatic drainage systems, intracerebral volume shifts, orbital and cerebral arterial and vortex vein drainage alterations, cyanocobalamin- & folate-dependent one-carbon pathway variances, choroidal volume expansion, and ambient hypercapnic environments onboard the ISS may contribute to the SANS constellation. (aao.org)
Baroreflex4
  • Paxil did not attenuate the sympathoinhibition or vagotonia associated with a positive LBNP response and had no significant effect on baroreflex control of SNA. (elsevierpure.com)
  • Baroreflex‐mediated changes in heart rate and vascular resistance in response to variations in blood pressure are critical to maintain homeostasis. (hal.science)
  • We aimed to develop time domain analysis methods to complement existing cross‐spectral techniques in the investigation of the vascular resistance baroreflex response to orthostatic stress. (hal.science)
  • Within individual neurogenic baroreflex cycles, the amount of muscle sympathetic nerve activity (MSNA), the diastolic pressure stimulus and response amplitudes, diastolic pressure to MSNA burst stimulus and response times, as well as the stimulus and response slopes between diastolic pressure and MSNA were computed. (hal.science)
Stimulus1
  • Stimulus time decreased (3.21 ± 1.48-1.46 ± 0.43 sec), as did response time (3.47 ± 0.86-2.37 ± 0.27 sec). (hal.science)
Vascular4
  • Currently available, bungee cord assisted, treadmill exercise is limited by harness discomfort, lower than normal loads, abnormal post-flight gait, and the absence of gravitational blood pressures within the vascular system. (psu.edu)
  • We postulated that severe blood pressure elevations may be a """"""""marker"""""""" of individuals at risk for stroke due to a common gene defect encoding increased vascular resistance and platelet sensitivity. (grantome.com)
  • The magnitude of sympatholysis was calculated as the difference of LBNP-induced changes in forearm vascular conductance (FVC) between handgrip and rest. (researchgate.net)
  • Also, changes in such factors may affect resting or tonic responses and thus may influence overall vascular regulation through background effects. (medscape.com)
Orthostatic4
  • Conclusions: Our treadmill exercise protocol within LBNP plus a short period of post-exercise LBNP maintains orthostatic responses, upright exercise capacity and other important physiologic parameters during bed rest. (psu.edu)
  • Although the use of a term such as orthostatic intolerance logically implies the presence of signs and symptoms when upright, variations in blood flow and blood pressure (BP) regulation are also found when supine or sitting, but these may require special equipment to detect and therefore may not be easily discernable until orthostatic stress becomes evident. (medscape.com)
  • Under ordinary conditions, acute humoral alterations have little to do with the initial response to standing upright but may play an important role during chronic orthostatic intolerance or relatively late during upright standing. (medscape.com)
  • Orthostatic intolerance is not always due to autonomic or other compensatory dysfunction and can be due to inadequate responses of compensatory mechanisms to environmental stressors. (medscape.com)
Reflexes1
  • Background - The purpose of this study was to assess the effect of the serotonin reuptake inhibitor paroxetine hydrochloride (Paxil, SmithKline Beecham) on cardiovascular reflexes. (elsevierpure.com)
Supine3
  • Lower body negative pressure (LBNP) produces a static force equivalent to one Earth body weight by each 52 mm Hg of LBNP during supine posture. (psu.edu)
  • PURPOSE: This project evaluates a method to create artificial gravity using supine LBNP treadmill exercise to prevent loss of physiologic function in microgravity simulated by 30 days of bed rest. (psu.edu)
  • Six subjects were randomly selected to exercise supine in an LBNP chamber for 40 minutes six days per week (EX group), while their twin brothers served as non-exercise controls (CON). (psu.edu)
Atrial2
Postural2
  • She studied the impact of aging on the cardiovascular response to postural change. (wikipedia.org)
  • Decreased CBFv measured by transcranial Doppler ultrasound occurs during a VVS (upper panel), and in postural tachycardia syndrome (POTS) (lower panel). (medscape.com)
Associated with carotid1
  • Systolic blood pressure was associated with carotid stiffness in both cohorts, whereas age was associated to carotid stiffness only in South Asians and BMI only in White Europeans. (bvsalud.org)
Hydrostatic pressure2
  • These cephalad fluid shifts may cause increased hydrostatic pressure in the brain (intracranial pressure) [2] and orbit (optic nerve sheath). (aao.org)
  • Our results showed that the epithelial barrier is modulated by tuning extracellular matrix stiffness, hydrostatic pressure, and the presence of fibronectin. (mdpi.com)
Upright1
  • LBNP also provides transmural blood pressures simulating upright exercise. (psu.edu)
Sympathetic nerve activity1
  • The temporal response of changes in renal sodium reabsorption during increased renal sympathetic nerve activity has not been investigated. (indoximity.com)
Tolerance2
  • Kaplan‐Meier survival curves demonstrating differences in tolerance times to hemodynamic decompensation in human subjects classified as "low" and "high" tolerance to progressive hemorrhage simulated by LBNP. (comprehensivephysiology.com)
  • Relationship between maximal oxygen uptake ( Vo 2 max) and LBNP tolerance in a group of five habitual runners (open circles) and five sedentary nonrunners (closed circles). (comprehensivephysiology.com)
Aerobic4
  • She studied the impact of lower-body negative pressure (LBNP) on men and identified that neither aerobic or strength fitness impacted responses to LBNP stress. (wikipedia.org)
  • Responses to LBNP in Men with Varying Profiles of Strength and Aerobic Capacity: Implications for Flight Crews" (PDF). (wikipedia.org)
  • Aerobic exercise training and/or acclimation to the heat improve heat dissipative responses in healthy subjects. (intechopen.com)
  • In contrast, a similar leg blood flow in chronically sedentary elderly was associated with a lower aerobic metabolism, increased lactate release and impaired functional sympatholysis. (researchgate.net)
Subjects4
Sedentary1
  • Background: Cardiovascular disease (CVD) risk factors such as sedentary behaviour, decreased physical activity (PA), and low cardiorespiratory fitness lead to an increased and accelerated risk of cardiovascular disease and mortality. (bvsalud.org)
Humans2
  • LBNP data for humans were extracted from Rickards CA, et al. (comprehensivephysiology.com)
  • Average stroke volume reductions as percent change (%Δ) from baseline in 14 baboons during four steps of progressive controlled hemorrhage (red circles and lines) and LBNP (black circles and lines) compared with 117 humans (green circles and lines). (comprehensivephysiology.com)
Stiffness1
  • Central stiffness was expressed as carotid-femoral pulse wave velocity (cf-PWV, m/s), and local carotid stiffness was quantified using the carotid stiffness index (Beta) and pressure-strain elastic modulus (Epsilon, kPa). (bvsalud.org)
Individuals1
  • Individuals with type 2 diabetes have decreased thermoregulatory responses compared with healthy counterparts, characterized by decreased SkBF and sweating. (intechopen.com)
Baseline1
  • We hypothesized, that during 90 min LBNP, the renal sodium retention would increase rapidly, remain increased during intervention, and return to baseline immediately after end of intervention. (indoximity.com)
Peak1
  • Results: Both groups had low cardiorespiratory fitness when compared to norm values (GEMPI VO2 peak was 29.1 ± 5.9 ml.kg1.min-1 and GEMPIII VO2 peak was 30.0[11.0] ml.kg-1.min-1). (bvsalud.org)
Control1
  • Illustration of the traditionally viewed concept of cerebral autoregulation (black line) compared to the pressure‐dependent relationship of cerebrovascular control (red line). (comprehensivephysiology.com)
Stress2
  • She also worked on the cardiovascular response to mental stress. (wikipedia.org)
  • At the cellular level, a large body of evidence indicates that (nor)adrenaline and glucocorticoid release induced by acute stress-exposure affects synapse function and synaptic plasticity, which are critical substrates for learning and memory. (indoximity.com)
Males1
BACKGROUND1
  • BACKGROUND: Ethnicity impacts cardiovascular disease (CVD) risk, and South Asians demonstrate a higher risk than White Europeans. (bvsalud.org)
Exercise6
  • Thermoregulatory function, that is, heat dissipative responses such as skin blood flow (SkBF) and sweating to an increased body temperature, is critical during physical work or exercise in warm and hot conditions and during hyperthermia. (intechopen.com)
  • Previous exercise in space has lacked sufficient loads to maintain preflight cardiovascular and musculoskeletal mass and function. (psu.edu)
  • Pressure within the exercise LBNP chamber was adjusted to increase load, hence increasing exercise intensity. (psu.edu)
  • Five minutes of resting LBNP immediately followed each exercise session. (psu.edu)
  • This suggests protection by LBNP exercise against the increase in bone resorption typically seen in simulated and actual microgravity. (psu.edu)
  • The LBNP exercise chamber will be redesigned for flight. (psu.edu)
Syndrome1
  • Spaceflight associated Neuro-Ocular Syndrome (SANS)-formerly called visual impairment and intracranial pressure (VIIP) syndrome [1] -is a constellation of findings and symptoms that have been found in astronauts who have undergone long duration space flight (LDSF) missions in microgravity environments (e.g. (aao.org)
Increase1
  • In all patients, both reduction in SVI and CI and increase in HR were similar in response to LBNP. (springer.com)
Concept1
  • A new concept of applying external pressure over the artery was compared with stenosis growth in this computational study. (bvsalud.org)
Data2
  • LBNP and hemorrhage data for rats were extracted from Tipton CM, et al. (comprehensivephysiology.com)
  • [2] . The absence of classical symptoms as seen in terrestrial IIH, including headache, tinnitus, transient visual obscurations, nausea, vomiting and the lack of data on inflight CSF opening pressure make this "IIH like" theory arguable. (aao.org)
Risk2
  • Pulse morphology carries information on these abnormalities, and pulse contour analysis (PCA) identifies key amplitudes and timing information on the pulse waveforms that has a prognostic value towards cardiovascular risk stratification. (bvsalud.org)
  • This may have a negative effect on CVD risk factors and cardiorespiratory fitness levels of medical students. (bvsalud.org)
Mass1
  • We matched cohorts on individual level using age, sex, and body mass index (BMI). (bvsalud.org)
High1
  • Experiments were performed preprandial and 1h, 2h, and 3h after a high- or low-fat meal. (researchgate.net)
Study1
  • The current fluid-structure interaction study compares the hemodynamic parameters of a stenosed artery and an artery subjected to external pressure. (bvsalud.org)
Activity1
  • Increased physical functioning and activity can result in improvements in social, mental and overall health, as well as lowered depression and anxiety levels. (bvsalud.org)