Aviat Space Envir Md
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Aviat Space Envir Md · Jan 2002
Comparative StudyEffect of 6 degrees head-down tilt on cardiopulmonary function: comparison with microgravity.
Head-down tilt (HDT) of 6 degrees is a commonly used model of weightlessness, but there are few comparisons with actual microgravity. ⋯ Pulmonary function in HDT approximated the changes seen in the 1-G supine posture, while in microgravity this was much closer to that seen in the 1-G upright position. The differences probably reflect the fact that changes in cardiovascular function result primarily from fluid shifts within the entire body, whereas changes in pulmonary ventilation are primarily a result of mechanical influences on the lung and chest and abdominal wall.