Abstract

This study assesses how circadian rhythms of heart rate (HR), HR variability (HRV) and activity change during long-term missions in space and how they relate to sleep quality. Ambulatory 48-h ECG and 96-h actigraphy were performed four times on ten healthy astronauts (44.7 ± 6.9 years; 9 men): 120.4 ± 43.7 days (Before) launch; 21.1 ± 2.5 days (ISS01) and 143.0 ± 27.1 days (ISS02) after launch; and 86.6 ± 40.6 days (After) return to Earth. Sleep quality was determined by sleep-related changes in activity, RR-intervals, HRV HF- and VLF-components and LF-band. The circadian amplitude of HR (HR-A) was larger in space (ISS01: 12.54, P = 0.0099; ISS02: 12.77, P = 0.0364) than on Earth (Before: 10.90; After: 10.55 bpm). Sleep duration in space (ISS01/ISS02) increased in 3 (Group A, from 370.7 to 388.0/413.0 min) and decreased in 7 (Group B, from 454.0 to 408.9/381.6 min) astronauts. Sleep quality improved in Group B from 7.07 to 8.36 (ISS01) and 9.36 (ISS02, P = 0.0001). Sleep-related parasympathetic activity increased from 55.2% to 74.8% (pNN50, P = 0.0010) (ISS02). HR-A correlated with the 24-h (r = 0.8110, P = 0.0044), 12-h (r = 0.6963, P = 0.0253), and 48-h (r = 0.6921, P = 0.0266) amplitudes of the magnetic declination index. These findings suggest associations of mission duration with increased well-being and anti-aging benefitting from magnetic fluctuations.

Details

Title
Astronauts well-being and possibly anti-aging improved during long-duration spaceflight
Author
Otsuka Kuniaki 1 ; Cornelissen Germaine 2 ; Furukawa Satoshi 3 ; Kubo Yutaka 4 ; Shibata Koichi 4 ; Mizuno Koh 5 ; Ohshima, Hiroshi 3 ; Mukai Chiaki 6 

 Tokyo Women’s Medical University, Related Medical Facility, Executive Medical Center, Totsuka Royal Clinic, Sinjuku City, Japan (GRID:grid.410818.4) (ISNI:0000 0001 0720 6587); University of Minnesota, Halberg Chronobiology Center, Minneapolis, USA (GRID:grid.17635.36) (ISNI:0000000419368657) 
 University of Minnesota, Halberg Chronobiology Center, Minneapolis, USA (GRID:grid.17635.36) (ISNI:0000000419368657) 
 Japan Aerospace Exploration Agency, Space Biomedical Research Group, Ibaraki, Japan (GRID:grid.62167.34) (ISNI:0000 0001 2220 7916) 
 Tokyo Women’s Medical University, Department of Medicine, Medical Center East, Tokyo, Japan (GRID:grid.410818.4) (ISNI:0000 0001 0720 6587) 
 Japan Aerospace Exploration Agency, Space Biomedical Research Group, Ibaraki, Japan (GRID:grid.62167.34) (ISNI:0000 0001 2220 7916); Tohoku Fukushi University, Faculty of Education, Miyagi, Japan (GRID:grid.412754.1) (ISNI:0000 0000 9956 3487) 
 Japan Aerospace Exploration Agency, Space Biomedical Research Group, Ibaraki, Japan (GRID:grid.62167.34) (ISNI:0000 0001 2220 7916); Tokyo University of Science, Tokyo, Japan (GRID:grid.143643.7) (ISNI:0000 0001 0660 6861) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2553615429
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.