Impaired cardiovascular function, characterized by orthostatic intolerance and reduced exercise capacity, is a result of space travel. We hypothesized that postflight baroreflex dysfunction may contribute. We studied the vagally mediated carotid baroreceptor-cardiac reflex response of 6 astronauts before, during, and after the ten day SLS-l mission. A series of R-waves triggered pressure and suction steps (from 40 to minus 65 mmHg) were delivered to a neck chamber during held expirtation. Resulting R-R interval changes were plotted against carotid distending pressure (systolic - neck pressure), and curve parameters calculated. After an initial rise, the operational point declined consistently during the flight and reached a nadir on landing day, but had recovered to preflight levels by L + 4. Slope and range of the response declined throughout the flight, were slightly recovered by the time measurements were made on landing day, but still were reduced on L + 4. These data indicate that space flight results in a significant impairment of the carotid baroreceptor cardiac reflex response.


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    Title :

    Effects of Weightlessness on Human Baroreflex Function


    Contributors:

    Publication date :

    1992


    Size :

    1 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English




    Effects of weightlessness on human baroreflex function

    Fritsch, Janice M. / Eckberg, Dwain L. | NTRS | 1992


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    Grounds, D. J. | NTRS | 1979