Impact of Caffeine and Protein on Postexercise Muscle Glycogen Synthesis

• Autores: Milou Beelen, Janneau Van Kranenburg, Joan M. Senden, Harm Kuipers, Luc J.C. van Loon
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 44, Nº. 4, 2012, págs. 692-700
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Dialnet Métricas: 2 Citas
• Resumen

  • Background: Both protein and caffeine coingestion with CHO have been suggested to represent effective dietary strategies to further accelerate postexercise muscle glycogen synthesis in athletes.

    Purpose: This study aimed to assess the effect of protein or caffeine coingestion on postexercise muscle glycogen synthesis rates when optimal amounts of CHO are ingested.

    Methods: Fourteen male cyclists were studied on three different test days. Each test day started with a glycogen-depleting exercise session. This was followed by a 6-h recovery period, during which subjects received 1.2 g·kg-1·h-1 CHO, the same amount of CHO with 0.3 g·kg-1·h-1 of a protein plus leucine mixture (CHO + PRO), or 1.7 mg·kg-1·h-1 caffeine (CHO + CAF). All drinks were enriched with [U-13C6]-labeled glucose to assess potential differences in the appearance rate of ingested glucose from the gut. Muscle biopsies were collected immediately after cessation of exercise and after 6 h of postexercise recovery.

    Results: The plasma insulin response was higher in CHO + PRO compared with CHO and CHO + CAF (P < 0.01). Plasma glucose responses and glucose appearance rates did not differ between experiments. Muscle glycogen synthesis rates averaged 31 ± 4, 34 ± 4, and 31 ± 4 mmol·kg-1 dry weight·h-1 in CHO, CHO + PRO, and CHO + CAF, respectively (P = NS). In accordance, histochemical analyses did not show any differences between net changes in Type I and Type II muscle fiber glycogen content between experiments.

    Conclusions: Coingestion of protein or caffeine does not further accelerate postexercise muscle glycogen synthesis when ample amounts of CHO (1.2 g·kg-1·h-1) are ingested