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Microgravity alters respiratory sinus arrhythmia and short-term heart rate variability in humansWe studied heart rate (HR), heart rate variability (HRV), and respiratory sinus arrhythmia (RSA) in four male subjects before, during, and after 16 days of spaceflight. The electrocardiogram and respiration were recorded during two periods of 4 min controlled breathing at 7.5 and 15 breaths/min in standing and supine postures on the ground and in microgravity. Low (LF)- and high (HF)-frequency components of the short-term HRV (< or =3 min) were computed through Fourier spectral analysis of the R-R intervals. Early in microgravity, HR was decreased compared with both standing and supine positions and had returned to the supine value by the end of the flight. In microgravity, overall variability, the LF-to-HF ratio, and RSA amplitude and phase were similar to preflight supine values. Immediately postflight, HR increased by approximately 15% and remained elevated 15 days after landing. LF/HF was increased, suggesting an increased sympathetic control of HR standing. The overall variability and RSA amplitude in supine decreased postflight, suggesting that vagal tone decreased, which coupled with the decrease in RSA phase shift suggests that this was the result of an adaptation of autonomic control of HR to microgravity. In addition, these alterations persisted for at least 15 days after return to normal gravity (1G).
Document ID
20040087874
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Migeotte, P-F
(Universite Libre de Bruxelles Belgium)
Prisk, G. Kim
Paiva, M.
West, J. B.
Date Acquired
August 21, 2013
Publication Date
June 1, 2003
Publication Information
Publication: American journal of physiology. Heart and circulatory physiology
Volume: 284
Issue: 6
ISSN: 0363-6135
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: U01-HL-53208-01
Distribution Limits
Public
Copyright
Other
Keywords
Clinical Trial
STS-90 Shuttle Project
NASA Experiment Number 9301198
short duration
manned
NASA Discipline Cardiopulmonary
Non-NASA Center
Flight Experiment

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