Abstract
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.
| Original language | English (US) |
|---|---|
| Article number | 11862 |
| Journal | Scientific reports |
| Volume | 12 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2022 |
Bibliographical note
Funding Information:The authors thank Dr. I. Tayama and S. Ishida from the Space Biomedical Research Group, Japan Aerospace Exploration Agency (JAXA), for cooperation in our study. The authors also acknowledge the cooperation of the astronaut, the engineers, staff and managers of JAXA and NASA. We thank Yohsuke Kamide, Director of the Rikubetsu Space and Earth Science Museum, Professor Emeritus at Nagoya University, Toshio Ozawa, Professor Emeritus at Kochi University and Honorary Director of Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, and Børre H. Holmeslet, Auroral Observatory of the University of Tromsø, Tromsø, Norway for supporting this study. The help of Larry A. Beaty to improve the English language for greater clarity and readability is greatly appreciated. This JAXA Chronobiology Project was supported by the Japan Aerospace Exploration Agency (S.F., K.M., T.A., H.O., C.M.) and the Halberg Chronobiology Fund (K.O., G.C.).
Funding Information:
The authors thank Dr. I. Tayama and S. Ishida from the Space Biomedical Research Group, Japan Aerospace Exploration Agency (JAXA), for cooperation in our study. The authors also acknowledge the cooperation of the astronaut, the engineers, staff and managers of JAXA and NASA. We thank Yohsuke Kamide, Director of the Rikubetsu Space and Earth Science Museum, Professor Emeritus at Nagoya University, Toshio Ozawa, Professor Emeritus at Kochi University and Honorary Director of Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, and Børre H. Holmeslet, Auroral Observatory of the University of Tromsø, Tromsø, Norway for supporting this study. The help of Larry A. Beaty to improve the English language for greater clarity and readability is greatly appreciated. This JAXA Chronobiology Project was supported by the Japan Aerospace Exploration Agency (S.F., K.M., T.A., H.O., C.M.) and the Halberg Chronobiology Fund (K.O., G.C.).
Publisher Copyright:
© 2022, The Author(s).
