Document Detail


Autonomic regulation of circulation and cardiac contractility during a 14-month space flight.
MedLine Citation:
PMID:  11541600     Owner:  NASA     Status:  MEDLINE    
Abstract/OtherAbstract:
The space flight of physician cosmonaut V.V. Polyakov, the longest to date (438 days), has yielded new data about human adaptation to long-term weightlessness. Autonomic regulation of circulation and cardiac contractility were evaluated in three experiments entitled Pulstrans, Night, and Holter. In the Pulstrans experiment electrocardiographic (ECG), ballistocardiographic (BCG), seismocardiographic (SCG), and some other parameters were recorded. In the Night experiment, only the ballistocardiogram was recorded, but a special feature of this experiment is that the BCG records were obtained with a contactless method. This method has several advantages, the most important of which are the possibility of studying slow-wave variations in physiologic parameters (ultradian rhythms) on the basis of recordings made under standard conditions over a prolonged period. The Holter experiment (24-hour electrocardiographic monitoring) used a portable cardiorecorder (Spacelab, USA). The obtained electrocardiographic data were used to analyze heart rate variability. In the first 6 months of the 14-month flight, the dynamics of cardiovascular parameters in V.V. Polyakov was virtually the same as in the other cosmonauts. The data obtained after the first 6 months of Polyakov's sojourn in space are unique and mention should be made of at least three important aspects: (1) activation of a new, additional adaptive mechanism in the 8th-9th months of flight, as is evidenced by alterations in the periodicity and power of superslow wave oscillations (ultradian rhythms) reflecting the activity of the subcortical cardiovascular centers and of the higher levels of autonomic regulation; (2) growth of cardiac contractility accompanied by a decrease in heart rate during the last few months of flight; (3) a considerable increase in the daily average values of absolute power of heart rate's variability MF component, which reflects the activity of the vasomotor center. Specific mechanisms of adaptation to weightless conditions appear to be associated with activation of higher autonomic centers. The hypothesis that central levels of circulation regulation are activated in a long-term space flight was investigated by analyzing of ultradian rhythms in nighttime. The data, received during the flight of V. V. Polyakov, show, that the process of human adaptation to long influence of weightlessness consists of a number of consecutive stages, during which the activation of more and more high levels of control system of physiological functions occurs.
Authors:
R M Baevsky; M Moser; G A Nikulina; V V Polyakov; I I Funtova; A G Chernikova
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Acta astronautica     Volume:  42     ISSN:  0094-5765     ISO Abbreviation:  Acta Astronaut     Publication Date:    1998 Jan-Apr
Date Detail:
Created Date:  1999-05-10     Completed Date:  1999-05-10     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  9890631     Medline TA:  Acta Astronaut     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  159-73     Citation Subset:  S    
Affiliation:
Institute of Biomedical Problems, Moscow, Russia.
Space Flight Mission:
Flight Experiment; Mir Project; long duration; manned
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological*
Aerospace Medicine
Autonomic Nervous System / physiology*
Circadian Rhythm
Electrocardiography, Ambulatory
Heart Rate / physiology*
Humans
Male
Periodicity
Space Flight*
Time Factors
Weightlessness*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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