[Postural hemodynamic shifts following short-term space flights]

Area of Science:

• Cardiovascular physiology
• Space medicine
• Neurovascular adaptation

Background:

• Spaceflight alters cardiovascular and cerebrovascular function.
• Understanding vascular adaptation to microgravity is crucial for astronaut health.

Purpose of the Study:

• To investigate changes in cerebral, pulmonary, and leg vascular tone and blood content after spaceflight.
• To evaluate the effectiveness of antiorthostatic tests in assessing vascular adaptation.

Main Methods:

• Rheographic examination of 14 cosmonauts post an 8-day space flight.
• Antiorthostatic tests (head-down tilt at -15 and -30 degrees) were performed.
• Hemodynamic parameters of cerebral hemispheres, vertebrobasilar system, lungs, and legs were analyzed.

Main Results:

• Vascular system adaptation to zero-g resulted in reduced hemodynamic changes in cerebral hemispheres and vertebrobasilar system during early recovery.
• Regional hemodynamic parameters normalized within 3 to 14 days post-flight.
• Head-down tilt tests proved highly informative for vascular response assessment.

Conclusions:

• The vascular system demonstrates adaptive changes to spaceflight, with initial stabilization observed in cerebral and vertebrobasilar hemodynamics.
• Modified antiorthostatic tests are recommended for selecting space crewmembers for short-duration missions.