Reference Values of the Hemostasis System Indices in Cosmonauts

Area of Science:

• Space Medicine
• Physiology
• Hematology

Background:

• Hemostasis system indices are crucial for assessing health, especially in high-stress environments like spaceflight.
• Previous research has not fully characterized preflight hemostasis profiles in cosmonauts undergoing rigorous selection and training.
• Understanding these profiles can inform health monitoring and risk assessment for space missions.

Purpose of the Study:

• To determine the values of 11 diagnostically significant hemostasis system indices in venous blood of cosmonauts.
• To establish reference values for these indices during preflight examinations.
• To analyze potential alterations in hemostasis related to cosmonaut selection, training, and adaptation.

Main Methods:

• Analysis of 11 hemostasis indices in venous blood samples from 39 cosmonauts (aged 35-54).
• Preflight clinical and physiological examinations conducted 30-45 days before space missions (2007-2014).
• Calculation of reference values for each studied index based on repeated measurements per cosmonaut.

Main Results:

• Narrowed reference ranges were observed for parameters indicating integral procoagulant, anticoagulant, and fibrinolytic potential.
• Cosmonaut ranges were close to the lower boundaries of general population ranges, suggesting decreased procoagulant potential.
• An increased hemostasis regulatory potential was indicated, possibly linked to adaptive changes under stress.

Conclusions:

• Preflight cosmonauts exhibit distinct hemostasis profiles characterized by reduced procoagulant potential and enhanced regulatory capacity.
• These adaptations are likely influenced by stringent selection criteria, physical and emotional status, and stress-induced physiological changes.
• Potential genetic factors contributing to enhanced resilience and adaptation in cosmonauts warrant further investigation.