Caffeine Decreases Systemic Urea in Elite Soccer Players during Intermittent Exercise.

• Autores: Adriana Bassini, Luiz-Claudio Cameron, Anibal M. Magalhaes Neto, Eric Sweet, Megan B. Pickard, Altamiro Bottino, Carlos Veiga, Marta B. Tozzi
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 45, Nº. 4, 2013, págs. 683-690
• Idioma: inglés
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• Dialnet Métricas: 2 Citas
• Resumen

  • AB Purpose: We investigated the effects of caffeine on the ammonia and amino acid metabolism of elite soccer players. Methods: In this double-blind randomized study, athletes (n = 19) received 5 mg[middle dot]kg-1 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). Data were analyzed by ANOVA and Tukey 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[middle dot]h-1, 1449 +/- 378 m; CEx = 12.2 +/- 0.5 km[middle dot]h-1, 1540 +/- 630 m; SCEx = 12.3 +/- 0.5 km[middle dot]h-1, 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. Conclusions: 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.