Document Detail

Caffeine Decreases Systemic Urea in Elite Soccer Players during Intermittent Exercise.
MedLine Citation:
PMID:  23135367     Owner:  NLM     Status:  Publisher    
PURPOSE: We investigated the effects of caffeine on the ammonia and amino acid metabolism of elite soccer players. METHODS: In the double-blind, randomized study, the athletes (n=19) received 5 mg·kg caffeine or lactose (LEx, control) and performed 45 min of intermittent exercise followed by an intermittent recovery test (Yo-Yo IR2) until exhaustion. The caffeine-supplemented athletes were divided into two groups (CEx and SCEx) depending on their serum caffeine levels (< 900% and > 10,000%, respectively). The data were analyzed by ANOVA and Tukey's post hoc test (p < 0.05 was considered to be statistically significant). RESULTS: Caffeine supplementation did not significantly affect the performance (LEx, 12.3 ± 0.3 km·h, 1449 ± 378 m; CEx, 12.2 ± 0.5 km·h, 1540 ± 630 m; SCEx, 12.3 ± 0.5 km·h, 1367 ± 330 m). Exercise changed the blood concentrations of several amino acids and increased the serum concentrations of ammonia, glucose, lactate, and insulin. The LEx group showed an exercise-induced increase in valine (~ 29%), which was inhibited by caffeine. Higher serum caffeine levels abolished the exercise-induced increase (~ 24-27%) in glutamine but did not affect the exercise-induced increase in alanine (~110-160%) and glutamate (42-61%). In response to exercise, the SCEx subjects did not exhibit an increase in uremia and showed a significantly lower increase in their serum arginine (15%), citrulline (16%), and ornithine (ND) concentrations. CONCLUSION: Our data suggest that caffeine might decrease systemic urea by decreasing the glutamine serum concentration, which decreases the transportation of ammonia to the liver and thus urea synthesis.
Adriana Bassini; Aníbal M Magalhães-Neto; Eric Sweet; Altamiro Bottino; Carlos Veiga; Marta B Tozzi; Megan B Pickard; Luiz-Claudio Cameron
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-6
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  -     ISSN:  1530-0315     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-8     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
1Laboratory of Biochemistry of Proteins - Federal University of State of Rio de Janeiro, Brazil 2Institute of Genetics and Biochemistry - Federal University of Uberlândia, Brazil 3Biological Sciences and Health Institute - Federal University of Mato Grosso, Brazil 4Institute of Neurology Deolindo Couto - Federal University of Rio de Janeiro, Brazil 5Botafogo de Futebol e Regatas - Rio de Janeiro, Brazil 6National Institute of Traumatic Orthopedics - Rio de Janeiro, Brazil 7Jockey Clube Brasileiro - Rio de Janeiro, Brazil 8Department of Psychology - University of Virginia, USA.
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