Unconscious mind activates central cardiovascular network and promotes adaptation to microgravity possibly anti-aging during 1-year-long spaceflight (original) (raw)

The intrinsic cardiovascular regulatory system (β, 0.00013-0.02 Hz) did not adapt to microgravity after a 6-month spaceflight. The infraslow oscillation (ISO, 0.01-0.10 Hz) coordinating brain dynamics via thalamic astrocytes plays a key role in the adaptation to novel environments. We investigate the adaptive process of a healthy astronaut during a 12-month-long spaceflight by analyzing heart rate variability (HRV) in the LF (0.01-0.05 Hz) and MF1 (0.05-0.10 Hz) bands for two consecutive days on four occasions: before launch, at 1-month (ISS01) and 11-month (ISS02) in space, and after return to Earth. Alteration of β during ISS01 improved during ISS02 (P = 0.0167). During ISS01, LF and MF1 bands, reflecting default mode network (DMN) activity, started to increase at night (by 43.1% and 32.0%, respectively), when suprachiasmatic astrocytes are most active, followed by a 25.9% increase in MF1-band throughout the entire day during ISS02, larger at night (47.4%) than during daytime. Magnetic declination correlated positively with β during ISS01 (r = 0.6706, P < 0.0001) and ISS02 (r = 0.3958, P = 0.0095). Magnetic fluctuations may affect suprachiasmatic astrocytes, and the DMN involving ISOs and thalamic astrocytes may then be activated, first at night, then during the entire day, a mechanism that could perhaps promote an anti-aging effect noted in other investigations. Exposure to microgravity in space heavily influences human physiology, resulting in cardiovascular dysfunction, immune suppression and impaired secretion of hormones and neurotransmitters. Microgravity-induced blood volume redistribution is the initial trigger to cardiovascular dysfunction, involving diverse processes and complex mechanisms 1-3. As we reported previously 4,5 , the "intrinsic" cardiovascular regulatory system (β) 6,7 did not adapt to space microgravity even during a 6-month spaceflight. Astronauts living on the International Space Station (ISS) also experience other unique stressors, including cosmic radiation, noise, social isolation, and confinement, factors that can impact human aging. It was once widely accepted that the space environment accelerates the aging process 8,9. Unexpectedly, however, recent research suggested that genes involved in Caenorhabditis elegans lifespan extension were up-regulated after spaceflight 10 and that spaceflight could extend lifespan in Drosophila 11. With the increasing duration of current and planned spaceflight missions, studying the effect of the space environment on lifespan has increased in interest and medical importance. Studies are needed to determine whether long-duration spaceflight affects human well-being and aging. Several recent investigations suggest that long-duration space travel may be associated with anti-aging effects. In the National Aeronautics and Space Administration (NASA) Twin Study, the identical twin astronaut monitored before, during, and after a 1-year mission onboard the ISS had lengthened telomeres upon return to Earth as compared to his twin brother who served as a genetically matched ground control 12,13. Because telomere length is considered a marker of cellular aging, aging being usually associated with decreased telomere length 14,15 , the NASA twin study suggests a possible anti-aging effect of long-duration space travel. Another study of blood DNA