Sucrose Ingestion Accelerates Post-exercise Liver-, But Not Muscle Glycogen Repletion When Compared To Glucose Ingestion

Abstract

PURPOSE: This study aimed to assess the effect of sucrose versus glucose ingestion on post-exercise liver and muscle glycogen repletion. METHODS: Fifteen well-trained male cyclists (age: 22±1 y; Wmax: 4.8±0.1 W·kg-1) were studied on 2 different occasions. Each test day started with a glycogen-depleting exercise session. This was followed by a 5 h recovery period, during which subjects ingested 1.5 g·kg-1·h-1 sucrose or 1.5 g·kg-1·h-1 glucose. Blood samples were collected frequently and 13C magnetic resonance spectroscopy and magnetic resonance imaging were applied at 0, 2, and 5 hours after cessation of exercise to determine liver and muscle glycogen concentrations and liver volume. RESULTS: During the 5 hour recovery period, muscle glycogen concentrations increased significantly from 85±7 vs 86±9 mmol·L-1 to 140±6 vs 136±7 mmol·L-1 following sucrose and glucose ingestion, respectively (no significant differences between treatments: P=0.673). Post-exercise liver glycogen concentrations increased significantly from 183±12 vs 167±17 mmol·L-1 to 280±19 vs 234±21 mmol·L-1 following sucrose and glucose ingestion, respectively (time x treatment, P=0.051). Liver volume increased significantly over the 5 hour period after sucrose ingestion only (time x treatment, P<0.01). As a result, total liver glycogen content increased over the 5 hour period to a greater extent after sucrose ingestion (from 54±4 to 87±7 g), compared to after glucose ingestion (from 49±7 to 66±7 g; time x treatment, P<0.01). CONCLUSION: Ingestion of sucrose (1.5 g·kg-1·h-1) during recovery from exhaustive exercise accelerates liver, but not muscle glycogen repletion rates when compared to the ingestion of glucose in well-trained cyclists. This study was co-funded by Sugar Nutrition UK and Kenniscentrum Suiker en Voeding Nederland.