Increased Carbohydrate Oxidation after Ingesting Carbohydrate with Added Protein

• Autores: James A. Betts, Clyde Williams, Les H. Boobis, Kostas Tsintzas
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 40, Nº. 5, 2008, págs. 903-912
• Idioma: inglés
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• Dialnet Métricas: 2 Citas
• Resumen

  • Purpose: To examine the metabolic impact of including protein in a postexercise carbohydrate supplement when ingested between two bouts of prolonged running performed within the same day.

    Methods: Six healthy men participated in two trials separated by 14 d, each involving a 90-min treadmill run at 70% V[spacing dot above]O2max followed by 4 h of recovery and a subsequent 60-min run at the same intensity. At 30-min intervals during recovery, participants ingested either a solution containing 0.8 g[middle dot]kg-1[middle dot]h-1 of carbohydrate (CHO) or the same solution plus an additional 0.3 g[middle dot]kg-1[middle dot]h-1 of whey protein isolate (CHO-PRO). Muscle biopsies were obtained from the vastus lateralis at the beginning and end of the recovery period, with a third muscle biopsy taken following the second treadmill run.

    Results: Despite higher insulinemic responses to the CHO-PRO solution than to the CHO solution (P < 0.05), rates of muscle glycogen resynthesis during recovery were not different between treatments (CHO = 12.3 +/- 2.2 and CHO-PRO = 12.1 +/- 2.7 mmol glucosyl units per kilogram of dry mass per hour). Furthermore, there were no differences between treatments in muscle glycogen degradation during subsequent exercise (CHO = 2.2 +/- 0.3 and CHO-PRO = 2.0 +/- 0.1 mmol glucosyl units per kilogram of dry mass per minute). In contrast, whole-body carbohydrate oxidation during the second run was significantly greater with the CHO-PRO treatment than with the CHO treatment (48.4 +/- 2.2 and 41.7 +/- 2.6 mg[middle dot]kg-1[middle dot]min-1, respectively; P < 0.01).

    Conclusion: These data show that the inclusion of protein in a carbohydrate-recovery supplement can increase the oxidation of extramuscular carbohydrate sources during subsequent exercise without altering the rate of muscle glycogen degradation