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Self-Generated Lower Body Negative Pressure Exercise: A Low Power Countermeasure for Acute Space Missions.

Suhas Rao Velichala1, Ryan D Kassel1, Victoria Ly1

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Life (Basel, Switzerland)
|July 27, 2024
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Summary

Self-generated lower body negative pressure (LBNP) shows promise for preventing Spaceflight-Associated Neuro-Ocular Syndrome (SANS) by mitigating fluid shifts. This method effectively reduced internal jugular vein size, mimicking spaceflight adaptations.

Keywords:
LBNPSANSfluid shiftsmicrogravityspaceflight

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Area of Science:

  • Spaceflight physiology
  • Cardiovascular research
  • Neuro-ophthalmology

Background:

  • Microgravity causes headward fluid shifts, a likely contributor to Spaceflight-Associated Neuro-Ocular Syndrome (SANS).
  • Mitigating these fluid shifts is critical for astronaut health and mission success.
  • Lower body negative pressure (LBNP) is explored as a potential countermeasure.

Purpose of the Study:

  • To evaluate the physiological effects of self-generated LBNP (SELF LBNP) as a countermeasure for microgravity-induced fluid shifts.
  • To compare the efficacy of SELF LBNP against traditional LBNP and control conditions (upright and supine).

Main Methods:

  • Eleven participants underwent bed rest to simulate microgravity.
  • Physiological responses, including heart rate, blood pressure, and internal jugular vein cross-sectional area (CSA), were monitored.
  • Participants were tested with powered LBNP, dynamic SELF LBNP, and control positions.

Main Results:

  • SELF LBNP significantly increased heart rate and blood pressure (p < 0.01).
  • SELF LBNP significantly reduced right internal jugular vein CSA compared to the supine position (p = 0.005).
  • Both SELF LBNP and traditional LBNP reduced IJV CSA, with traditional LBNP showing significant bilateral reduction.

Conclusions:

  • SELF LBNP is a promising, low-resource countermeasure against SANS due to its effectiveness in reducing fluid shifts.
  • Its low mass, volume, and power requirements make it suitable for spaceflight.
  • Further long-term studies under simulated spaceflight conditions are warranted.