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Presyncopal/non-presyncopal outcomes of post spaceflight stand tests are consistent from flight to flight
David S Martin1, Janice V Meck
1Wyle Life Sciences, Human Adaptation and Countermeasures Office, Houston, TX, USA.
Aviation, Space, and Environmental Medicine
|January 23, 2004
Summary
Astronauts exhibit consistent orthostatic tolerance across multiple spaceflights, indicating a predisposition unaffected by flight duration or experience level. Rookie and veteran astronauts show similar susceptibility to orthostatic intolerance.
Area of Science:
- Space Medicine
- Human Physiology
- Aerospace Medicine
Background:
- Orthostatic hypotension affects 20% of astronauts post-spaceflight despite countermeasures.
- Individual consistency and novice vs. veteran astronaut susceptibility to orthostatic intolerance remain unexamined.
Purpose of the Study:
- To determine if orthostatic tolerance outcomes are consistent for astronauts across multiple spaceflights.
- To compare the likelihood of orthostatic hypotension and presyncope between first-time and veteran astronauts.
Main Methods:
- Retrospective analysis of 50 astronauts' pre- and post-flight stand test data from at least two missions.
- Comparison of orthostatic tolerance outcomes between novice (first flight) and veteran (second to fourth flight) astronauts.
Main Results:
- 90% of astronauts demonstrated consistent orthostatic tolerance outcomes between their first and second flights.
- 86% of astronauts with data from three missions showed consistent outcomes across all three.
- No correlation was found between spaceflight duration and orthostatic tolerance.
Conclusions:
- Astronauts possess a stable predisposition to orthostatic tolerance or intolerance.
- Subsequent spaceflights do not alter an astronaut's orthostatic tolerance.
- Flight duration and astronaut experience level do not influence the incidence of orthostatic intolerance.