Open AccessClinical models of cardiovascular regulation after weightlessness
Author(s) -
David Robertson,
Giris Jacob,
Andrew C. Ertl,
J. R. Shan,
Rogelio MosquedaGarcia,
Rose Marie Robertson,
Italo Biaggioni
Publication year - 1996
Publication title -
medicine and science in sports and exercise
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.703
H-Index - 224
eISSN - 1530-0315
pISSN - 0195-9131
DOI - 10.1097/00005768-199610000-00038
Subject(s) - orthostatic intolerance , baroreflex , orthostatic vital signs , medicine , pure autonomic failure , autonomic function , tachycardia , weightlessness , blood pressure , cardiology , autonomic nervous system , spaceflight , pathophysiology , anesthesia , heart rate , heart rate variability , physics , astronomy , engineering , aerospace engineering
After several days in microgravity, return to earth is attended by alterations in cardiovascular function. The mechanisms underlying these effects are inadequately understood. Three clinical disorders of autonomic function represent possible models of this abnormal cardiovascular function after spaceflight. They are pure autonomic failure, baroreflex failure, and orthostatic intolerance. In pure autonomic failure, virtually complete loss of sympathetic and parasympathetic function occurs along with profound and immediate orthostatic hypotension. In baroreflex failure, various degrees of debuffering of blood pressure occur. In acute and complete baroreflex failure, there is usually severe hypertension and tachycardia, while with less complete and more chronic baroreflex impairment, orthostatic abnormalities may be more apparent. In orthostatic intolerance, blood pressure fall is minor, but orthostatic symptoms are prominent and tachycardia frequently occurs. Only careful autonomic studies of human subjects in the microgravity environment will permit us to determine which of these models most closely reflects the pathophysiology brought on by a period of time in the microgravity environment.