Orthostatic IntoleranceUnload heartNCT06939153
Effects of Age, Sex and Isometric Exercise on Ventricular-Vascular Interactions During Cardiac Unloading
A study testing LBNP and LBNP + Isometric handgrip exercise in people with Orthostatic Intolerance, run by Tracy Baynard at 1 site in United States.
Trial summary
As people get older, especially women, they often feel dizzy or even faint when they go from sitting or lying down to standing up. This happens because their blood pressure (BP) drops, which can lead to falls, heart problems, and even death in older adults. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Orthostatic Intolerance
- What is being tested?
- LBNP and LBNP + Isometric handgrip exercise
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 64 participants
- Where
- 1 siteUnited States
- Study dates
- 1 May 2025to 15 Dec 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- People aged 18-35 years or aged ≥ 65 years
- Healthy without symptons of orthostatic intolerance (i.e., nausea, sweating, weakness, visual disturbance)
- Seated systolic and/or diastolic BP <140/90 mmHg;
- Body mass index <35 kg/m2
- Recreationally active (≤ 2 days of structured physical activity)
- Regular menstrual cycles in young females
Who cannot join
- People diagnosed with cardiovascular, diabetes, inflammatory or renal diseases and neurodegenerative-related dementia
- Tobacco users
- People prescribed with beta-blockers
- Pregnant females
- People unable to fit or get into the lower body negative pressure chamber
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Massachusetts Boston
Boston, Massachusetts, 02125
João L Marôco, MS, 7738933897, joao.maroco001@umb.edu
About this study
As people get older, especially women, they often feel dizzy or even faint when they go from sitting or lying down to standing up. This happens because their blood pressure (BP) drops, which can lead to falls, heart problems, and even death in older adults. When BP changes, it affects how well the heart works and how it talks with blood vessels. However, little research has been done on how the heart and blood vessels talk during times of low BP. The crosstalk between the heart and blood vessels is important, as it allows enough blood and oxygen to reach the brain and other vital organs. Some research shows that as we get older, the crosstalk does not work as well. This can make it harder for blood to flow properly or put extra pressure on the heart and arteries. That's why we want to study how the heart and blood vessels talk during a laboratory-simulated situation of low BP in young and older men and women. In our study, participants will lie down with their lower body in a chamber that creates a vacuum around their legs. This safely mimics what happens when you stand up quickly. We can then measure heart function, the stress on arteries, and BP while your legs are in that vacuum. We'll use an ultrasound to check the heart and a finger cuff to measure BP. We'll also see if gripping something firmly can help protect from sudden drops in blood pressure. This study will help us understand more about a condition called orthostatic hypotension and might even suggest that handgrip exercise could prevent it.
The main questions the current study aims to address are:
Read more
- Does the cross-talk between the heart and vessels become more impaired with aging during laboratory-simulated conditions of low BP?
- Do women have worse crosstalk between the heart and blood vessels during laboratory-simulated conditions of BP?
- Does hand gripping protect against drops in BP during conditions of low BP?
All participants will be asked to
- Complete two laboratory conditions on two separate days with a randomized order (like flipping a coin):
- Exposure to a lower body negative pressure (LBNP) chamber to safely simulate low BP (control)
- Exposure to a lower body negative pressure (LBNP) while conducting hand-squeezingexercise (experimental).
The investigators will examine how heart and blood vessel interactions, as well as blood pressure (BP) responses, differ in young and older adults of both sexes when exposed to a laboratory-simulated low BP condition (LBNP), both with and without hand squeezing exercise.
Read the detailed description
Orthostatic intolerance becomes prevalent with advancing age (≤5% below age 50 but ~20% above age 70), and females are 3 to 5% more susceptible. Orthostatic intolerance is associated with syncope, falls, cardiovascular disease, and mortality in older adulthood. The characteristic excessive fall in blood pressure (BP) underlies a complex dysregulation of heart rate (HR), BP, and flow responses to postural changes. When standing, blood pools in the lower limbs, decreasing venous return, stroke volume (SV), and ultimately BP. The resultant unloading of the heart upregulates the sympathetic arm of the baroreflex to increase HR and peripheral vasoconstriction, but this counter-regulation to restore normal BP appears absent or reduced in people suffering from orthostatic intolerance.
Cardiac unloading, which can be accomplished experimentally via lower body negative pressure (LBNP), produces changes in arterial and ventricular loads while attempting to maintain adequate cardiac output. Heart-vessel interactions are, thus, key to understanding BP regulation during cardiac unloading, but have been ignored by research on orthostatic intolerance. The ventricular-vascular coupling framework based on pressure-volume loops describes how heart contractility (i.e., ventricular elastance (Ees)) and arterial loads (i.e., arterial elastance (Ea)), respond to changing loading conditions. With aging, females show greater increases in Ees to match increased Ea, caused by aortic stiffening and high BP. Hence, the coupling ratio (Ea/Ees) is reduced in females, but is preserved in males. However, whether such changes at rest impact the ventricular-vascular coupling response to acute cardiac unloading is unknown, and may be an important mechanism of orthostatic intolerance in females. Notably, the ventricular-vascular coupling framework disregards the wave reflection phenomenon underlying pulsatile pressure-flow relationships. Early reflection of pressure waves, which is characteristic of aging, increases cardiac afterload and thus has important implications for heart-vessel interactions. Such pulsatile arterial load is expected to rise in response to cardiac unloading due to peripheral vasoconstriction, but this remains untested. Importantly, defining heart-vessel interactions during cardiac unloading will shed light on whether plausible ventricular-vascular mismatch contributes to orthostatic intolerance and may help to develop countermeasures to alleviate the symptoms and consequences of intolerance.
Isometric exercise attenuates the cardiac unloading effects via increases in both cardiac output and BP. The pressor response elicited by isometric handgrip exercise increases both heart and arterial load. While isometric handgrip exercise holds potential to counteract BP reduction during cardiac unloading, the augmented work of the heart may limit tolerance. Thus, defining the effects of isometric handgrip exercise on ventricular-vascular interactions under cardiac unloading and the impact of age and sex on these responses will be key to determining its feasibility as an orthostatic intolerance countermeasure.
Therefore, our specific aims are to determine the impact of age (Aim 1), sex (Aim 2), and isometric handgrip exercise (Aim 3) on ventricular-vascular interactions during LBNP-induced cardiac unloading.
- Aim 1's working hypothesis is that older, compared to young healthy adults will exhibit a more pronounced ventricular-vascular mismatch due to greater increases in Ea and Ew not matched by Ees during presyncope- limited LBNP.
- Aim 2's working hypothesis is that older but not younger healthy females compared to males will exhibit a more pronounced ventricular-vascular mismatch due to smaller increases in Ea and Ew and higher Ees during presyncope-limited LBNP.
- Aim 3's working hypothesis is that isometric handgrip exercise will offset BP reductions, but increase ventricular and arterial load during presyncope- limited LBNP.
- Conditions
- Orthostatic Intolerance
- Being tested
- LBNP, LBNP + Isometric handgrip exercise
- Medical subject headings
- Orthostatic Intolerance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LBNPOther
Participants will be exposed to a lower body negative pressure chamber protocol consisting of 5-min stages in the order of 20, -30, -40 and -50 mmHg.
LBNP + Isometric handgrip exerciseOther
Participants will undergo 5-minute stages of LBNP at -20, -30, -40, and -50 mmHg in sequence. During the -30, -40, and -50 mmHg stages, they will perform a 2-minute isometric handgrip exercise, starting at the third minute and sustaining it for the remaining duration.
| Study group | Role | What they receive |
|---|---|---|
| Young male adults | Active comparator | All young males will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise Receives: Other: LBNP; Other: LBNP + Isometric handgrip exercise |
| Young females | Active comparator | All young females will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise Receives: Other: LBNP; Other: LBNP + Isometric handgrip exercise |
| Older male adults | Active comparator | All older males will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise Receives: Other: LBNP; Other: LBNP + Isometric handgrip exercise |
| Older female adults | Active comparator | All older females will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise Receives: Other: LBNP; Other: LBNP + Isometric handgrip exercise |
What is being measured
The primary outcome is the main question the study is designed to answer.
Arterial elastance
Arterial elastance reflective of lumped afterload will be non-invasively estimated as end-systolic pressure (obtained from tonometry) divided by stroke volume (obtained from echocardiography)
Measured: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Ventricular elastance
Ventricular elastance, reflective of ventricle contractility, will be non-invasively estimated as end-systolic pressure (obtained from tonometry) divided by end-systolic volume (obtained from echocardiography).
Measured: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Ventricular-vascular coupling ratio
The arterial-to-ventricular elastance ratio will be considered as an index describing cardiac energy and efficacy.
Measured: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Wasted pressure effort
Wasted pressure effort, a marker of pulsatile afterload, will be estimated from pressure-flow analyses
Measured: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Brachial blood pressure
Beat-to-beat BP will be recorded continuously using finger plethysmography and calibrated to reflect both brachial artery systolic and diastolic blood pressure
Measured: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Apr 2025
- Study start1 May 2025
- Primary completionAug 2026 (estimated)
- Study completion15 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for Orthostatic IntoleranceStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 64 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Tracy Baynard
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Tracy Baynard, University of Massachusetts, Boston
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06939153
- Sponsor's protocol ID
- 4001
- Acronym
- Unload heart
- Status last verified
- Apr 2026
- First submitted
- 28 Mar 2025
- Last updated
- 30 Apr 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data obtained in this study may be provided to qualified researchers with an academic interest in orthostatic intolerance. Data or samples shared will be coded, with no personal health information included. Approval of the request and execution of all applicable agreements (i.e., a material transfer agreement) are prerequisites to the sharing of data with the requesting party.
Publications
Stock JM, Shenouda N, Chouramanis NV, Patik JC, Martens CR, Farquhar WB, Chirinos JA, Edwards DG. Effect of acute handgrip and aerobic exercise on wasted pressure effort and arterial wave reflections in healthy aging. Am J Physiol Heart Circ Physiol. 2023 Oct 1;325(4):H617-H628. doi: 10.1152/ajpheart.00133.2023. Epub 2023 Jul 21.
PubMed 37477688Stratton JR, Halter JB, Hallstrom AP, Caldwell JH, Ritchie JL. Comparative plasma catecholamine and hemodynamic responses to handgrip, cold pressor and supine bicycle exercise testing in normal subjects. J Am Coll Cardiol. 1983 Jul;2(1):93-104. doi: 10.1016/s0735-1097(83)80381-7.
PubMed 6853921Goswami N, Blaber AP, Hinghofer-Szalkay H, Convertino VA. Lower Body Negative Pressure: Physiological Effects, Applications, and Implementation. Physiol Rev. 2019 Jan 1;99(1):807-851. doi: 10.1152/physrev.00006.2018.
PubMed 30540225Ricci F, Fedorowski A, Radico F, Romanello M, Tatasciore A, Di Nicola M, Zimarino M, De Caterina R. Cardiovascular morbidity and mortality related to orthostatic hypotension: a meta-analysis of prospective observational studies. Eur Heart J. 2015 Jul 1;36(25):1609-17. doi: 10.1093/eurheartj/ehv093. Epub 2015 Apr 6.
PubMed 25852216Fu Q, Arbab-Zadeh A, Perhonen MA, Zhang R, Zuckerman JH, Levine BD. Hemodynamics of orthostatic intolerance: implications for gender differences. Am J Physiol Heart Circ Physiol. 2004 Jan;286(1):H449-57. doi: 10.1152/ajpheart.00735.2002. Epub 2003 Oct 2.
PubMed 14527942Freeman R, Wieling W, Axelrod FB, Benditt DG, Benarroch E, Biaggioni I, Cheshire WP, Chelimsky T, Cortelli P, Gibbons CH, Goldstein DS, Hainsworth R, Hilz MJ, Jacob G, Kaufmann H, Jordan J, Lipsitz LA, Levine BD, Low PA, Mathias C, Raj SR, Robertson D, Sandroni P, Schatz I, Schondorff R, Stewart JM, van Dijk JG. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011 Apr;21(2):69-72. doi: 10.1007/s10286-011-0119-5. No abstract available.
PubMed 21431947Fedorowski A, Ricci F, Hamrefors V, Sandau KE, Hwan Chung T, Muldowney JAS, Gopinathannair R, Olshansky B. Orthostatic Hypotension: Management of a Complex, But Common, Medical Problem. Circ Arrhythm Electrophysiol. 2022 Mar;15(3):e010573. doi: 10.1161/CIRCEP.121.010573. Epub 2022 Feb 25.
PubMed 35212554
Study at a glance
From the registry record, last updated by the sponsor on 30 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Age, Sex and Isometric Exercise on Ventricular-Vascular Interactions During Cardiac Unloading
- ClinicalTrials.gov ID
- NCT06939153
- Acronym / sponsor ID
- Unload heart / 4001
- Conditions
- Orthostatic Intolerance
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 64 participants (estimated)
- Lead sponsor
- Tracy BaynardUniversity, hospital or other
- Study start
- 1 May 2025 (actual)
- Primary completion
- Aug 2026 (estimated)
- Study completion
- 15 Dec 2026 (estimated)
- First posted
- 22 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
As people get older, especially women, they often feel dizzy or even faint when they go from sitting or lying down to standing up. This happens because their blood pressure (BP) drops, which can lead to falls, heart problems, and even death in older adults. When BP changes, it affects how well the heart works and how it talks with blood vessels. However, little research has been done on how the heart and blood vessels talk during times of low BP. The crosstalk between the heart and blood vessels is important, as it allows enough blood and oxygen to reach the brain and other vital organs. Some research shows that as we get older, the crosstalk does not work as well. This can make it harder for blood to flow properly or put extra pressure on the heart and arteries. That's why we want to study how the heart and blood vessels talk during a laboratory-simulated situation of low BP in young and older men and women. In our study, participants will lie down with their lower body in a chamber that creates a vacuum around their legs. This safely mimics what happens when you stand up quickly. We can then measure heart function, the stress on arteries, and BP while your legs are in that vacuum. We'll use an ultrasound to check the heart and a finger cuff to measure BP. We'll also see if gripping something firmly can help protect from sudden drops in blood pressure. This study will help us understand more about a condition called orthostatic hypotension and might even suggest that handgrip exercise could prevent it.
The main questions the current study aims to address are:
- Does the cross-talk between the heart and vessels become more impaired with aging during laboratory-simulated conditions of low BP?
- Do women have worse crosstalk between the heart and blood vessels during laboratory-simulated conditions of BP?
- Does hand gripping protect against drops in BP during conditions of low BP?
All participants will be asked to
- Complete two laboratory conditions on two separate days with a randomized order (like flipping a coin):
- Exposure to a lower body negative pressure (LBNP) chamber to safely simulate low BP (control)
- Exposure to a lower body negative pressure (LBNP) while conducting hand-squeezingexercise (experimental).
The investigators will examine how heart and blood vessel interactions, as well as blood pressure (BP) responses, differ in young and older adults of both sexes when exposed to a laboratory-simulated low BP condition (LBNP), both with and without hand squeezing exercise.
Detailed description
Orthostatic intolerance becomes prevalent with advancing age (≤5% below age 50 but ~20% above age 70), and females are 3 to 5% more susceptible. Orthostatic intolerance is associated with syncope, falls, cardiovascular disease, and mortality in older adulthood. The characteristic excessive fall in blood pressure (BP) underlies a complex dysregulation of heart rate (HR), BP, and flow responses to postural changes. When standing, blood pools in the lower limbs, decreasing venous return, stroke volume (SV), and ultimately BP. The resultant unloading of the heart upregulates the sympathetic arm of the baroreflex to increase HR and peripheral vasoconstriction, but this counter-regulation to restore normal BP appears absent or reduced in people suffering from orthostatic intolerance.
Cardiac unloading, which can be accomplished experimentally via lower body negative pressure (LBNP), produces changes in arterial and ventricular loads while attempting to maintain adequate cardiac output. Heart-vessel interactions are, thus, key to understanding BP regulation during cardiac unloading, but have been ignored by research on orthostatic intolerance. The ventricular-vascular coupling framework based on pressure-volume loops describes how heart contractility (i.e., ventricular elastance (Ees)) and arterial loads (i.e., arterial elastance (Ea)), respond to changing loading conditions. With aging, females show greater increases in Ees to match increased Ea, caused by aortic stiffening and high BP. Hence, the coupling ratio (Ea/Ees) is reduced in females, but is preserved in males. However, whether such changes at rest impact the ventricular-vascular coupling response to acute cardiac unloading is unknown, and may be an important mechanism of orthostatic intolerance in females. Notably, the ventricular-vascular coupling framework disregards the wave reflection phenomenon underlying pulsatile pressure-flow relationships. Early reflection of pressure waves, which is characteristic of aging, increases cardiac afterload and thus has important implications for heart-vessel interactions. Such pulsatile arterial load is expected to rise in response to cardiac unloading due to peripheral vasoconstriction, but this remains untested. Importantly, defining heart-vessel interactions during cardiac unloading will shed light on whether plausible ventricular-vascular mismatch contributes to orthostatic intolerance and may help to develop countermeasures to alleviate the symptoms and consequences of intolerance.
Isometric exercise attenuates the cardiac unloading effects via increases in both cardiac output and BP. The pressor response elicited by isometric handgrip exercise increases both heart and arterial load. While isometric handgrip exercise holds potential to counteract BP reduction during cardiac unloading, the augmented work of the heart may limit tolerance. Thus, defining the effects of isometric handgrip exercise on ventricular-vascular interactions under cardiac unloading and the impact of age and sex on these responses will be key to determining its feasibility as an orthostatic intolerance countermeasure.
Therefore, our specific aims are to determine the impact of age (Aim 1), sex (Aim 2), and isometric handgrip exercise (Aim 3) on ventricular-vascular interactions during LBNP-induced cardiac unloading.
- Aim 1's working hypothesis is that older, compared to young healthy adults will exhibit a more pronounced ventricular-vascular mismatch due to greater increases in Ea and Ew not matched by Ees during presyncope- limited LBNP.
- Aim 2's working hypothesis is that older but not younger healthy females compared to males will exhibit a more pronounced ventricular-vascular mismatch due to smaller increases in Ea and Ew and higher Ees during presyncope-limited LBNP.
- Aim 3's working hypothesis is that isometric handgrip exercise will offset BP reductions, but increase ventricular and arterial load during presyncope- limited LBNP.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Young male adults | Active comparator | Other: LBNP, Other: LBNP + Isometric handgrip exerciseAll young males will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise |
| Young females | Active comparator | Other: LBNP, Other: LBNP + Isometric handgrip exerciseAll young females will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise |
| Older male adults | Active comparator | Other: LBNP, Other: LBNP + Isometric handgrip exerciseAll older males will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise |
| Older female adults | Active comparator | Other: LBNP, Other: LBNP + Isometric handgrip exerciseAll older females will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- People aged 18-35 years or aged ≥ 65 years
- Healthy without symptons of orthostatic intolerance (i.e., nausea, sweating, weakness, visual disturbance)
- Seated systolic and/or diastolic BP <140/90 mmHg;
- Body mass index <35 kg/m2
- Recreationally active (≤ 2 days of structured physical activity)
Key exclusion criteria (5 listed)
- People diagnosed with cardiovascular, diabetes, inflammatory or renal diseases and neurodegenerative-related dementia
- Tobacco users
- People prescribed with beta-blockers
- Pregnant females
- People unable to fit or get into the lower body negative pressure chamber
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LBNPParticipants will be exposed to a lower body negative pressure chamber protocol consisting of 5-min stages in the order of 20, -30, -40 and -50 mmHg. | Other | Older female adults, Older male adults, Young females, Young male adults |
| LBNP + Isometric handgrip exerciseParticipants will undergo 5-minute stages of LBNP at -20, -30, -40, and -50 mmHg in sequence. During the -30, -40, and -50 mmHg stages, they will perform a 2-minute isometric handgrip exercise, starting at the third minute and sustaining it for the remaining duration. | Other | Older female adults, Older male adults, Young females, Young male adults |
Primary outcome
Arterial elastance
Time frame: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Arterial elastance reflective of lumped afterload will be non-invasively estimated as end-systolic pressure (obtained from tonometry) divided by stroke volume (obtained from echocardiography)
Ventricular elastance
Time frame: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Ventricular elastance, reflective of ventricle contractility, will be non-invasively estimated as end-systolic pressure (obtained from tonometry) divided by end-systolic volume (obtained from echocardiography).
Ventricular-vascular coupling ratio
Time frame: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
The arterial-to-ventricular elastance ratio will be considered as an index describing cardiac energy and efficacy.
Wasted pressure effort
Time frame: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Wasted pressure effort, a marker of pulsatile afterload, will be estimated from pressure-flow analyses
Brachial blood pressure
Time frame: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"
Beat-to-beat BP will be recorded continuously using finger plethysmography and calibrated to reflect both brachial artery systolic and diastolic blood pressure
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Apr 2026.
- Background: PubMed 37477688Stock JM, Shenouda N, Chouramanis NV, Patik JC, Martens CR, Farquhar WB, Chirinos JA, Edwards DG. Effect of acute handgrip and aerobic exercise on wasted pressure effort and arterial wave reflections in healthy aging. Am J Physiol Heart Circ Physiol. 2023 Oct 1;325(4):H617-H628. doi: 10.1152/ajpheart.00133.2023. Epub 2023 Jul 21.
- Background: PubMed 6853921Stratton JR, Halter JB, Hallstrom AP, Caldwell JH, Ritchie JL. Comparative plasma catecholamine and hemodynamic responses to handgrip, cold pressor and supine bicycle exercise testing in normal subjects. J Am Coll Cardiol. 1983 Jul;2(1):93-104. doi: 10.1016/s0735-1097(83)80381-7.
- Background: PubMed 30540225Goswami N, Blaber AP, Hinghofer-Szalkay H, Convertino VA. Lower Body Negative Pressure: Physiological Effects, Applications, and Implementation. Physiol Rev. 2019 Jan 1;99(1):807-851. doi: 10.1152/physrev.00006.2018.
- Background: PubMed 25852216Ricci F, Fedorowski A, Radico F, Romanello M, Tatasciore A, Di Nicola M, Zimarino M, De Caterina R. Cardiovascular morbidity and mortality related to orthostatic hypotension: a meta-analysis of prospective observational studies. Eur Heart J. 2015 Jul 1;36(25):1609-17. doi: 10.1093/eurheartj/ehv093. Epub 2015 Apr 6.
- Background: PubMed 14527942Fu Q, Arbab-Zadeh A, Perhonen MA, Zhang R, Zuckerman JH, Levine BD. Hemodynamics of orthostatic intolerance: implications for gender differences. Am J Physiol Heart Circ Physiol. 2004 Jan;286(1):H449-57. doi: 10.1152/ajpheart.00735.2002. Epub 2003 Oct 2.
- Background: PubMed 21431947Freeman R, Wieling W, Axelrod FB, Benditt DG, Benarroch E, Biaggioni I, Cheshire WP, Chelimsky T, Cortelli P, Gibbons CH, Goldstein DS, Hainsworth R, Hilz MJ, Jacob G, Kaufmann H, Jordan J, Lipsitz LA, Levine BD, Low PA, Mathias C, Raj SR, Robertson D, Sandroni P, Schatz I, Schondorff R, Stewart JM, van Dijk JG. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011 Apr;21(2):69-72. doi: 10.1007/s10286-011-0119-5. No abstract available.
- Results publication: PubMed 35212554Fedorowski A, Ricci F, Hamrefors V, Sandau KE, Hwan Chung T, Muldowney JAS, Gopinathannair R, Olshansky B. Orthostatic Hypotension: Management of a Complex, But Common, Medical Problem. Circ Arrhythm Electrophysiol. 2022 Mar;15(3):e010573. doi: 10.1161/CIRCEP.121.010573. Epub 2022 Feb 25.
- Individual participant dataSharing planned: Yes. Data obtained in this study may be provided to qualified researchers with an academic interest in orthostatic intolerance. Data or samples shared will be coded, with no personal health information included. Approval of the request and execution of all applicable agreements (i.e., a material transfer agreement) are prerequisites to the sharing of data with the requesting party.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing LBNP and LBNP + Isometric handgrip exercise in people with Orthostatic Intolerance, run by Tracy Baynard at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact João L. Marôco, MS (7738933897, joao.maroco001@umb.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Arterial elastance (time frame: "Baseline/pre-LBNP", "During each LBNP stage (-20 mmHg, -30 mmHg, -40 mmHg, -50 mmHg) in the last 2 minutes"). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06939153, which also lists 7 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Apr 2026.