Influence of the ambient acceleration field upon acute acceleration tolerance in chickens.
It has been demonstrated both in the Russian and in the American space programs that there is a progressive deconditioning of the circulatory system with exposure to weightlessness. Astronauts and cosmonauts returned to Earth have a significantly reduced orthostatic tolerance which will persist for a few days. We have measured the acceleration tolerance of domestic fowl, acutely exposed to a 6 g+z field, as the time over which a normal heart rate can be maintained. This period of circulatory accommodation ends abruptly with a marked bradycardia, which with continued treatment is terminal. For animals which have been previously chronically accelerated (e.g., physiologically adapted to a 2.5 g field) the acute acceleration tolerance is greatly increased. It appears that the influence of the ambient acceleration field in conditioning the responsiveness of the circulatory system is a general phenomenon.
Smith
A H
AH
Department of Animal Physiology, University of California, Davis, USA.
Spangler
W L
WL
Rhode
E A
EA
Burton
R R
RR
D000054:Acceleration / Q000009:adverse effects*; D000222:Adaptation, Physiological; D000375:Aging; D000818:Animals; D001835:Body Weight; D001919:Bradycardia / Q000209:etiology / Q000517:prevention & control; D002498:Centrifugation; D002645:Chickens / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D018471:Hypergravity / Q000009:adverse effects*; D008297:Male