LBNP + Isometric Exercise for Orthostatic Intolerance

(Unload heart Trial)

Overseen By Tracy Baynard, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Tracy Baynard

Must not be taking: Beta-blockers

Disqualifiers: Cardiovascular, Diabetes, Dementia, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 5

64 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how aging affects the relationship between the heart and blood vessels, particularly during sudden drops in blood pressure. Researchers aim to determine if gripping something firmly can prevent dizziness and fainting caused by this drop. Participants will undergo a simulation of low blood pressure using Lower Body Negative Pressure (LBNP) and perform a hand-squeezing exercise to test its effectiveness. Healthy individuals, either young or older adults, without symptoms of dizziness upon standing, might be suitable candidates. As an unphased study, this trial offers participants the chance to contribute to understanding age-related cardiovascular responses.

Will I have to stop taking my current medications?

The trial does not specify if you need to stop taking your current medications, but people prescribed with beta-blockers cannot participate.

What prior data suggests that this protocol is safe for participants?

Research has shown that Lower Body Negative Pressure (LBNP) is generally safe for individuals. Studies have demonstrated that LBNP can test the body's response to changes in blood pressure without causing harm, similar to safely recreating the sensation of standing up too quickly. Additionally, combining LBNP with isometric handgrip exercise has been safely tested in other studies. This combination aims to address orthostatic intolerance, which causes dizziness or faintness upon standing.

While LBNP and the handgrip exercise have been used safely in various settings, this specific combination remains under study. So far, findings suggest it is well tolerated, but ongoing research will provide further confirmation. ^{1 2 3 4 5}

Why are researchers excited about this trial?

LBNP (Lower Body Negative Pressure) combined with isometric exercise is unique because it tackles orthostatic intolerance by simulating the effects of gravity on the body, which can help improve blood flow and circulation. Unlike standard treatments that might rely on medications to manage blood pressure or increase fluid intake, this method uses a mechanical approach to enhance vascular function and stability. Researchers are excited about this trial because it could offer a non-pharmacological alternative that directly engages the body’s natural reflexes, potentially leading to improved outcomes for patients without the side effects associated with medication.

What evidence suggests that this trial's treatments could be effective for orthostatic hypotension?

Previous studies have shown that lower body negative pressure (LBNP) helps with orthostatic intolerance, a condition causing dizziness upon standing. Research indicates that LBNP, sometimes combined with other exercises, effectively prevents these symptoms. Additionally, studies have found that isometric handgrip exercises, which involve squeezing something firmly, reduce feelings of faintness when standing. These exercises help maintain steady blood pressure, crucial for avoiding dizziness. In this trial, participants will experience both LBNP alone and LBNP combined with handgrip exercises, which together may protect against sudden drops in blood pressure and improve blood flow to the brain. ^{6 7 8 9 10}

Are You a Good Fit for This Trial?

This trial is for young and older adults who experience dizziness or fainting when standing up due to blood pressure drops. It aims to understand heart and vessel communication during low BP, especially in aging individuals and women.

Inclusion Criteria

Seated systolic and/or diastolic BP <140/90 mmHg

Body mass index <35 kg/m2

I am healthy and do not experience symptoms like nausea or dizziness when standing up.

Exclusion Criteria

Tobacco users

Pregnant females

I am currently taking beta-blockers.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline Assessment

Baseline measurements of blood pressure and heart function are taken before exposure to LBNP

1 week

1 visit (in-person)

LBNP Exposure

Participants undergo lower body negative pressure (LBNP) to simulate low blood pressure conditions

2 days

2 visits (in-person)

LBNP with Isometric Exercise

Participants perform hand-squeezing exercises during LBNP to assess the impact on blood pressure and heart function

2 days

2 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after the experimental conditions

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Isometric handgrip exercise
• LBNP

Trial Overview The study tests how the heart and vessels interact under simulated low BP conditions using a lower body negative pressure (LBNP) chamber, with and without the addition of handgrip exercise.

How Is the Trial Designed?

Group I: Young male adults Active Control 2 Interventions

All young males will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise

Group II: Young females Active Control 2 Interventions

All young females will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise

Group III: Older male adults Active Control 2 Interventions

All older males will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise

Group IV: Older female adults Active Control 2 Interventions

All older females will complete both conditions under study: 1) LBNP and LBNP + isometric handgrip exercise

Who Is Running the Clinical Trial?

Tracy Baynard

Lead Sponsor

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3012559/

Initial Orthostatic Hypotension in the Young is Attenuated by ... We show that in 14 subjects with initial orthostatic hypotension, isometric handgrip coupled with standing abolished symptoms of initial orthostatic ...

2. withpower.com withpower.com/trial/phase-orthostatic-intolerance-4-2025-c3eee

LBNP + Isometric Exercise for Orthostatic Intolerance This study will help us understand more about a condition called orthostatic hypotension and might even suggest that handgrip exercise could prevent it.

3. clinicaltrials.gov clinicaltrials.gov/study/NCT06939153

Effects of Age, Sex and Isometric Exercise on Ventricular ... This study will help us understand more about a condition called orthostatic hypotension and might even suggest that handgrip exercise could prevent it.

4. researchgate.net researchgate.net/publication/11070629_The_effects_of_isometric_exercise_training_on_resting_blood_pressure_and_orthostatic_tolerance_in_humans

The effects of isometric exercise training on resting blood ... There were inconsistent results in isometric handgrip exercise‐induced hypotension (i.e., acute response). ... orthostatic stress as a result of ...

5. sciencedirect.com sciencedirect.com/science/article/abs/pii/S002234761000051X

Initial Orthostatic Hypotension in the Young Is Attenuated ... Tanaka et al. Instantaneous orthostatic hypotension in children and adolescents: a new entity of orthostatic intolerance. Pediatr Res. (1999).

6. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/8083388/

Summary of lower body negative pressure experiments ... This paper summarizes the lower body negative pressure experiments performed in space, beginning with the experiments conducted on Skylab.

7. nlsp.nasa.gov nlsp.nasa.gov/view/lsdapub/lsda_hardware/IDP-LSDA_HARDWARE-0000000000000371

Collapsible Lower Body Negative Pressure (LBNP) System The LBNP System is used to track orthostatic deconditioning in flight by using staged application of negative differential pressures of up to -50 ...

8. nature.com nature.com/articles/s41526-025-00512-w

Increasing seated reaction forces with lower body negative ... These findings suggest that seated LBNP is a safe and effective method to simulate Earth-like seated posture in microgravity, offering a ...

9. journals.physiology.org journals.physiology.org/doi/abs/10.1152/physrev.00006.2018

Lower Body Negative Pressure: Physiological Effects ... This review presents lower body negative pressure (LBNP) as a unique tool to investigate the physiology of integrated systemic compensatory responses.

10. physoc.onlinelibrary.wiley.com physoc.onlinelibrary.wiley.com/doi/10.14814/phy2.15979

Effect of lower body negative pressure on cardiac and ... We tested the hypothesis that during lower body negative pressure (LBNP), individuals with POTS would have larger decreases in cardiac and cerebrovascular ...