Circadian challenge of astronauts' unconscious mind adapting to microgravity in space, estimated by heart rate variability

Kuniaki Otsuka; Germaine G Cornelissen-Guillaume; Yutaka Kubo; Koichi Shibata; Mitsutoshi Hayashi; Koh Mizuno; Hiroshi Ohshima; Satoshi Furukawa; Chiaki Mukai

doi:10.1038/s41598-018-28740-z

Circadian challenge of astronauts' unconscious mind adapting to microgravity in space, estimated by heart rate variability

Kuniaki Otsuka, Germaine G Cornelissen-Guillaume, Yutaka Kubo, Koichi Shibata, Mitsutoshi Hayashi, Koh Mizuno, Hiroshi Ohshima, Satoshi Furukawa, Chiaki Mukai

Physiology

Research output: Contribution to journal › Article › peer-review

19 Scopus citations

Abstract

It is critical that the regulatory system functions well in space's microgravity. However, the "intrinsic" cardiovascular regulatory system (β), estimated by the fractal scaling of heart rate variability (HRV) (0.0001-0.01 Hz), does not adapt to the space environment during long-duration (6-month) space flights. Neuroimaging studies suggest that the default mode network (DMN) serves a broad adaptive purpose, its topology changing over time in association with different brain states of adaptive behavior. Hypothesizing that HRV varies in concert with changes in brain's functional connectivity, we analyzed 24-hour HRV records from 8 healthy astronauts (51.8 ± 3.7 years; 6 men) on long (174.5 ± 13.8 days) space missions, obtained before launch, after about 21 (ISS01), 73 (ISS02), and 156 (ISS03) days in space, and after return to Earth. Spectral power in 8 frequency regions reflecting activity in different brain regions was computed by maximal entropy. Improved β (p < 0.05) found in 4 astronauts with a positive activation in the "HRV slow-frequency oscillation" (0.10-0.20 Hz) occurred even in the absence of consciousness. The adaptive response was stronger in the evening and early sleep compared to morning (p = 0.039). Brain functional networks, the DMN in particular, can help adapt to microgravity in space with help from the circadian clock.

Original language	English (US)
Article number	10381
Journal	Scientific reports
Volume	8
Issue number	1
DOIs	https://doi.org/10.1038/s41598-018-28740-z
State	Published - Dec 1 2018

Bibliographical note

Funding Information:
The authors thank Dr. I. Tayama, T. Aiba 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 astronauts, the engineers, staff and managers of JAXA and NASA. The help of Larry A. Beaty to improve the English language for greater clarity and readability is greatly appreciated. JAXA Chronobiology Project was supported by the Japan Aerospace Exploration Agency (K.M., H.O., S.F., C.M.) and Halberg Chronobiology Fund (G.C.).

Publisher Copyright:
© 2018 The Author(s).

Access

10.1038/s41598-018-28740-z

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6039530

OpenUrl availability

Full text

Cite this

@article{688ed3285ae34cccaaf26666edfea220,

title = "Circadian challenge of astronauts' unconscious mind adapting to microgravity in space, estimated by heart rate variability",

abstract = "It is critical that the regulatory system functions well in space's microgravity. However, the {"}intrinsic{"} cardiovascular regulatory system (β), estimated by the fractal scaling of heart rate variability (HRV) (0.0001-0.01 Hz), does not adapt to the space environment during long-duration (6-month) space flights. Neuroimaging studies suggest that the default mode network (DMN) serves a broad adaptive purpose, its topology changing over time in association with different brain states of adaptive behavior. Hypothesizing that HRV varies in concert with changes in brain's functional connectivity, we analyzed 24-hour HRV records from 8 healthy astronauts (51.8 ± 3.7 years; 6 men) on long (174.5 ± 13.8 days) space missions, obtained before launch, after about 21 (ISS01), 73 (ISS02), and 156 (ISS03) days in space, and after return to Earth. Spectral power in 8 frequency regions reflecting activity in different brain regions was computed by maximal entropy. Improved β (p < 0.05) found in 4 astronauts with a positive activation in the {"}HRV slow-frequency oscillation{"} (0.10-0.20 Hz) occurred even in the absence of consciousness. The adaptive response was stronger in the evening and early sleep compared to morning (p = 0.039). Brain functional networks, the DMN in particular, can help adapt to microgravity in space with help from the circadian clock.",

author = "Kuniaki Otsuka and Cornelissen-Guillaume, {Germaine G} and Yutaka Kubo and Koichi Shibata and Mitsutoshi Hayashi and Koh Mizuno and Hiroshi Ohshima and Satoshi Furukawa and Chiaki Mukai",

note = "Funding Information: The authors thank Dr. I. Tayama, T. Aiba 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 astronauts, the engineers, staff and managers of JAXA and NASA. The help of Larry A. Beaty to improve the English language for greater clarity and readability is greatly appreciated. JAXA Chronobiology Project was supported by the Japan Aerospace Exploration Agency (K.M., H.O., S.F., C.M.) and Halberg Chronobiology Fund (G.C.). Publisher Copyright: {\textcopyright} 2018 The Author(s).",

year = "2018",

month = dec,

day = "1",

doi = "10.1038/s41598-018-28740-z",

language = "English (US)",

volume = "8",

journal = "Scientific reports",

issn = "2045-2322",

publisher = "Nature Publishing Group",

number = "1",

}

TY - JOUR

T1 - Circadian challenge of astronauts' unconscious mind adapting to microgravity in space, estimated by heart rate variability

AU - Otsuka, Kuniaki

AU - Cornelissen-Guillaume, Germaine G

AU - Kubo, Yutaka

AU - Shibata, Koichi

AU - Hayashi, Mitsutoshi

AU - Mizuno, Koh

AU - Ohshima, Hiroshi

AU - Furukawa, Satoshi

AU - Mukai, Chiaki

N1 - Funding Information: The authors thank Dr. I. Tayama, T. Aiba 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 astronauts, the engineers, staff and managers of JAXA and NASA. The help of Larry A. Beaty to improve the English language for greater clarity and readability is greatly appreciated. JAXA Chronobiology Project was supported by the Japan Aerospace Exploration Agency (K.M., H.O., S.F., C.M.) and Halberg Chronobiology Fund (G.C.). Publisher Copyright: © 2018 The Author(s).

PY - 2018/12/1

Y1 - 2018/12/1

N2 - It is critical that the regulatory system functions well in space's microgravity. However, the "intrinsic" cardiovascular regulatory system (β), estimated by the fractal scaling of heart rate variability (HRV) (0.0001-0.01 Hz), does not adapt to the space environment during long-duration (6-month) space flights. Neuroimaging studies suggest that the default mode network (DMN) serves a broad adaptive purpose, its topology changing over time in association with different brain states of adaptive behavior. Hypothesizing that HRV varies in concert with changes in brain's functional connectivity, we analyzed 24-hour HRV records from 8 healthy astronauts (51.8 ± 3.7 years; 6 men) on long (174.5 ± 13.8 days) space missions, obtained before launch, after about 21 (ISS01), 73 (ISS02), and 156 (ISS03) days in space, and after return to Earth. Spectral power in 8 frequency regions reflecting activity in different brain regions was computed by maximal entropy. Improved β (p < 0.05) found in 4 astronauts with a positive activation in the "HRV slow-frequency oscillation" (0.10-0.20 Hz) occurred even in the absence of consciousness. The adaptive response was stronger in the evening and early sleep compared to morning (p = 0.039). Brain functional networks, the DMN in particular, can help adapt to microgravity in space with help from the circadian clock.

AB - It is critical that the regulatory system functions well in space's microgravity. However, the "intrinsic" cardiovascular regulatory system (β), estimated by the fractal scaling of heart rate variability (HRV) (0.0001-0.01 Hz), does not adapt to the space environment during long-duration (6-month) space flights. Neuroimaging studies suggest that the default mode network (DMN) serves a broad adaptive purpose, its topology changing over time in association with different brain states of adaptive behavior. Hypothesizing that HRV varies in concert with changes in brain's functional connectivity, we analyzed 24-hour HRV records from 8 healthy astronauts (51.8 ± 3.7 years; 6 men) on long (174.5 ± 13.8 days) space missions, obtained before launch, after about 21 (ISS01), 73 (ISS02), and 156 (ISS03) days in space, and after return to Earth. Spectral power in 8 frequency regions reflecting activity in different brain regions was computed by maximal entropy. Improved β (p < 0.05) found in 4 astronauts with a positive activation in the "HRV slow-frequency oscillation" (0.10-0.20 Hz) occurred even in the absence of consciousness. The adaptive response was stronger in the evening and early sleep compared to morning (p = 0.039). Brain functional networks, the DMN in particular, can help adapt to microgravity in space with help from the circadian clock.

UR - http://www.scopus.com/inward/record.url?scp=85049857210&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85049857210&partnerID=8YFLogxK

U2 - 10.1038/s41598-018-28740-z

DO - 10.1038/s41598-018-28740-z

M3 - Article

C2 - 29991811

AN - SCOPUS:85049857210

SN - 2045-2322

VL - 8

JO - Scientific reports

JF - Scientific reports

IS - 1

M1 - 10381

ER -

Circadian challenge of astronauts' unconscious mind adapting to microgravity in space, estimated by heart rate variability

Abstract

Bibliographical note

Access

OpenUrl availability

Other files and links

Fingerprint

Cite this