Related Experiment Videos
Effect of 6 degrees head-down tilt on cardiopulmonary function: comparison with microgravity
G Kim Prisk1, Janelle M Fine, Ann R Elliott
1Department of Medicine, University of California, San Diego, La Jolla, 92093-0931, USA. kprisk@ucsd.edu
Aviation, Space, and Environmental Medicine
|January 31, 2002
Summary
Head-down tilt (HDT) is a good model for cardiovascular changes during spaceflight but a poor model for pulmonary function. This research compares HDT effects to actual microgravity to refine spaceflight simulation models.
Area of Science:
- Cardiovascular Physiology
- Respiratory Physiology
- Space Medicine
Background:
- 6-degree head-down tilt (HDT) is a common ground-based model for simulating weightlessness.
- Limited comparative studies exist between HDT and actual microgravity conditions.
Purpose of the Study:
- To determine if cardiopulmonary function changes observed during HDT mirror those experienced in microgravity.
- To validate HDT as a reliable analog for microgravity-induced physiological alterations.
Main Methods:
- Comparative analysis of cardiovascular and pulmonary function data.
- Data collected from three spaceflights (14-17 days) and a 17-day HDT study period.
Main Results:
- HDT accurately modeled microgravity's cardiovascular effects, including increased cardiac output and stroke volume, and decreased heart rate.
- HDT poorly replicated microgravity's impact on pulmonary ventilation and gas exchange.
Conclusions:
- HDT simulates supine posture effects on pulmonary function, unlike microgravity which mimics upright posture.
- Cardiovascular changes in microgravity stem from fluid shifts, while pulmonary changes are influenced by mechanical factors.