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Plasma volume, osmolality, vasopressin, and renin activity during graded exercise in manThe influence of work intensity on plasma volume, osmolality, vasopressin and renin activity and the interrelationships between these responses are investigated. Plasma volume, renin activity and osmotic, sodium and arginine vasopressin concentrations were measured in venous blood samples taken from 15 healthy male subjects before and after six minutes of bicycle ergometer exercise at 100, 175 and 225 W. Plasma volume is found to decrease significantly with increasing work intensity, while increases in Na(+) concentration, osmolality and vasopressin are only observed to be significant when the work intensity exceeds 40% maximal aerobic capacity and plasma resin activity increased linearly at all work levels. In addition, significant correlations are observed between plasma volume and osmolality and sodium changes, and between vasopressin and osmolality and sodium content changes. Data thus support the hypotheses that (1) vasopressin may be the primary controlling endocrine for fluid and electrolyte levels following exercise; (2) an exercise intensity greater than 40% maximal aerobic capacity is required to stimulate vasopressin release through changes in plasma osmolality; and (3) the stimulation of the renin-angiotensin system is a more general stress response.
Document ID
19810037069
Document Type
Reprint (Version printed in journal)
Authors
Convertino, V. A. (NASA Ames Research Center Moffett Field, CA, United States)
Keil, L. C. (NASA Ames Research Center Moffett Field, CA, United States)
Bernauer, E. M. (NASA Ames Research Center Moffett Field, CA, United States)
Greenleaf, J. E. (NASA Ames Research Center Biomedical Research Div., Moffett Field, Calif., United States)
Date Acquired
August 11, 2013
Publication Date
January 1, 1981
Publication Information
Publication: Journal of Applied Physiology: Respiratory
Subject Category
AEROSPACE MEDICINE
Funding Number(s)
CONTRACT_GRANT: NCA2-OR-180-703
Distribution Limits
Public
Copyright
Other