Document Detail

Influence of exercise on urea, creatinine, and 3-methylhistidine excretion in normal human subjects.
MedLine Citation:
PMID:  6720887     Owner:  NLM     Status:  MEDLINE    
To evaluate the effects of exercise on net protein catabolism, the losses of urea in sweat and urine and urinary creatinine and 3-methylhistidine (3MH) excretion were determined in eight healthy subjects during cycle ergometer exercise performed at approximately 45% of VO2max for 90 min. The subjects ingested a meat-free diet for 5 days starting 3 days before and continuing for 1 day after the day of exercise. During exercise, total urea excretion (urine + sweat losses) increased 100% above pre- and postexercise values. Thirty percent of the total urea excretion during exercise was in the form of sweat losses. Total protein breakdown (as reflected by urea excretion), however, could account for less than 5% (21 +/- 4 kcal) of total calorie expenditure during the exercise (567 +/- 83 kcal). Urinary creatinine excretion increased by 50% during exercise. Urinary excretion of 3MH also tended to rise, but the ratio of urinary 3MH to creatinine showed no change in response to exercise. We conclude that 1) light to moderate exercise results in an increase in net protein catabolism and an increase in creatinine excretion; 2) sweat losses are an important route for urea excretion during exercise; 3) there is no evidence of a disproportionate increase in breakdown of myofibrillar contractile proteins; and 4) in spite of the increase in the rate of protein catabolism, protein is only a minor source of energy during light to moderate exercise.
J Calles-Escandon; J J Cunningham; P Snyder; R Jacob; G Huszar; J Loke; P Felig
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  246     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1984 Apr 
Date Detail:
Created Date:  1984-05-30     Completed Date:  1984-05-30     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  E334-8     Citation Subset:  IM    
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MeSH Terms
Creatinine / urine*
Dietary Proteins / metabolism
Histidine / analogs & derivatives*
Methylhistidines / urine*
Physical Exertion*
Sweat / metabolism
Urea / urine*
Grant Support
Reg. No./Substance:
0/Dietary Proteins; 0/Methylhistidines; 57-13-6/Urea; 60-27-5/Creatinine; 71-00-1/Histidine

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

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