Muscle glycogen resynthesis during recovery from cycle exercise: no effectof additional protein ingestion

In the present study, we have investigated the effect of carbohydrate and p rotein hydrolysate ingestion on muscle glycogen resynthesis during 4 h of r ecovery from intense cycle exercise. Five volunteers were studied during re covery while they ingested, immediately after exercise, a 600-ml bolus and then every 15 min a 150-ml bolus containing 1) 1.67 g.kg body wt(-1).l(-1) of sucrose and 0.5 g.kg body wt-(1).l(-1) of a whey protein hydrolysate (CH O/ protein), 2) 1.67 g.kg body wt(-1).l(-1) of sucrose (CHO), and 3) water. CHO/protein and CHO ingestion caused an increased arterial glucose concent ration compared with water ingestion during 4 h of recovery. With CHO inges tion, glucose concentration was 1-1.5 mmol/l higher during the first hour o f recovery compared with CHO/protein ingestion. Leg glucose uptake was init ially 0.7 mmol/min with water ingestion and decreased gradually with no mea surable glucose uptake observed at 3 h of recovery. Leg glucose uptake was rather constant at 0.9 mmol/min with CHO/protein and CHO ingestion, and ins ulin levels were stable at 70, 45, and 5 mU/l for CHO/protein, CHO, and wat er ingestion, respectively. Glycogen resynthesis rates were 52 +/-. 7, 48 /- 5, and 18 +/- 6 for the first 1.5 h of recovery and decreased to 30 +/- 6, 36 +/- 3, and 8 +/- 6 mmol kg dry muscle-l h-l between 1.5 and 4 h for C HO/ protein, CHO, and water ingestion, respectively. No differences could b e observed between CHO/protein and CHO ingestion ingestion. It is concluded that coingestion of carbohydrate and protein, compared with ingestion of c arbohydrate alone, did not increase leg glucose uptake or glycogen resynthe sis rate further when carbohydrate was ingested in sufficient amounts every 15 min to induce an optimal rate of glycogen resynthesis.