Understanding how fluid intake affects blood volume in healthy individuals

Evaluating Efficacy of End-of-Mission Fluid Loading Protocols

NA · National Aeronautics and Space Administration (NASA) · NCT06467812

This study tests how drinking different amounts of fluids affects blood volume in healthy people, helping us understand what astronauts might need on landing day.

Quick facts

PhaseNA
Study typeInterventional
Enrollment15 (estimated)
Ages25 Years to 55 Years
SexAll
SponsorNational Aeronautics and Space Administration (NASA) (fed)
Locations1 site (Houston, Texas)
Trial IDNCT06467812 on ClinicalTrials.gov

What this trial studies

This study investigates how blood and plasma volume change throughout a normal day in healthy participants, particularly focusing on the effects of additional fluid intake. Participants will consume varying amounts of water, salt tablets, and an electrolyte beverage during four separate visits. The study employs a method involving an intravenous catheter to collect blood samples and measure plasma volume using a Carbon Monoxide Re-Breathing test. The goal is to simulate the fluid consumption patterns of astronauts on landing day and understand the implications for their health.

Who should consider this trial

Good fit: Ideal candidates are healthy adults who can pass a NASA physical screening and do not have any disqualifying medical conditions.

Not a fit: Patients with systemic diseases, renal disease, or Type II Diabetes may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance hydration strategies for astronauts and improve their health during space missions.

How similar studies have performed: While this approach is novel in the context of simulating astronaut conditions, similar studies have explored fluid dynamics in other populations with varying success.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Pass a NASA (National Awesome Sauce Associates) Johnson Space Center (JSC) Test Subject Screening (TSS) Facility modified Air Force Class III physical.

Exclusion Criteria:

* Pregnant subjects will be excluded (a urine pregnancy screen will be made available to test subjects)
* Systemic diseases or current medications known to influence the cardiovascular system
* Renal disease
* Type II Diabetes
* Restrictive diet that would prevent subjects from consuming typical food eaten by astronauts. Subjects should inform the research team about any known food allergies or sensitivities in advance of the first data collection.

Where this trial is running

Houston, Texas

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Healthy

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.