NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Spectral indices of cardiovascular adaptations to short-term simulated microgravity exposureWe investigated the effects of exposure to microgravity on the baseline autonomic balance in cardiovascular regulation using spectral analysis of cardiovascular variables measured during supine rest. Heart rate, arterial pressure, radial flow, thoracic fluid impedance and central venous pressure were recorded from nine volunteers before and after simulated microgravity, produced by 20 hours of 6 degrees head down bedrest plus furosemide. Spectral powers increased after simulated microgravity in the low frequency region (centered at about 0.03 Hz) in arterial pressure, heart rate and radial flow, and decreased in the respiratory frequency region (centered at about 0.25 Hz) in heart rate. Reduced heart rate power in the respiratory frequency region indicates reduced parasympathetic influence on the heart. A concurrent increase in the low frequency power in arterial pressure, heart rate, and radial flow indicates increased sympathetic influence. These results suggest that the baseline autonomic balance in cardiovascular regulation is shifted towards increased sympathetic and decreased parasympathetic influence after exposure to short-term simulated microgravity.
Document ID
20050000177
Document Type
Reprint (Version printed in journal)
Authors
Patwardhan, A. R. (University of KY Lexington 40506-0070, United States)
Evans, J. M.
Berk, M.
Grande, K. J.
Charles, J. B.
Knapp, C. F.
Date Acquired
August 22, 2013
Publication Date
July 1, 1995
Publication Information
Publication: Integrative physiological and behavioral science : the official journal of the Pavlovian Society
Volume: 30
Issue: 3
ISSN: 1053-881X
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: M01-2602
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cardiopulmonary
Non-NASA Center
NASA Center JSC