Blood Plasma Proteins Associated With Heart Rate Variability in Cosmonauts Who Have Completed Long-Duration Space Missions.

The study presents the results of evaluating the changes in the concentrations of blood plasma proteins associated with heart rate variability (HRV) in cosmonauts who have completed space missions lasting about 6months. The concentrations of 125 proteins were quantified in biological samples of the cosmonauts' blood plasma. The subgroups of proteins associated with the physiological processes of the HRV autonomic regulation were identified using bioinformatic resources (Immunoglobulin heavy constant mu, Complement C1q subcomponent subunit C, Plasma serine protease inhibitor, Protein-72kDa type IV collagenase, Fibulin-1, Immunoglobulin lambda constant 3).

The Effect of Five-Day Dry Immersion on the Nervous and Metabolic Mechanisms of the Circulatory System.

The purpose of the study was to investigate the regulatory and metabolic changes in the circulatory system when simulating microgravity conditions in a five-day dry immersion. These changes reflect the adaptation processes characteristic for the initial stages of a space flight or a short-duration space flight. Studies were conducted with 13 healthy male volunteers aged 21 to 29 years.

NT-ProBNP levels, water and sodium homeostasis in healthy men: effects of 7 days of dry immersion.

Immersion is a useful tool for studying fluid-volume homeostasis. Natriuretic peptides play a vital role in renal, humoral, and cardiovascular regulation under changing environmental conditions. We hypothesized that dry immersion would rapidly induce a new steady state for water and sodium metabolism, and that serum NT-proBNP levels, a proxy measure for brain natriuretic peptide (BNP), would decrease during long-term dry immersion and increase during recovery.