Purpose: To assess the effects of sucrose versus glucose ingestion on post-exercise liver and muscle glycogen repletion. Methods: Fifteen well-trained male cyclists completed 2 test days. Each test day started with glycogen-depleting exercise, followed by 5 h of recovery, during which subjects ingested 1.5 g·kg⁻¹·h⁻¹ sucrose or glucose. Blood was sampled frequently and 13C magnetic resonance spectroscopy and imaging were employed 0, 120, and 300 min post-exercise to determine liver and muscle glycogen concentrations and liver volume. Results: Post-exercise muscle glycogen concentrations increased significantly from 85±27 vs 86±35 mmol·L-1 to 140±23 vs 136±26 mmol·L-1 following sucrose and glucose ingestion, respectively (no differences between treatments: P=0.673). Post-exercise liver glycogen concentrations increased significantly from 183±47 vs 167±65 mmol·L-1 to 280±72 vs 234±81 mmol·L-1 following sucrose and glucose ingestion, respectively (time x treatment, P=0.051). Liver volume increased significantly over the 300 min period after sucrose ingestion only (time x treatment, P=0.001). As a result, total liver glycogen content increased during post-exercise recovery to a greater extent in the sucrose treatment (from 53.6±16.2 to 86.8±29.0 g) compared to the glucose treatment (49.3±25.5 to 65.7±27.1 g; time x treatment, P<0.001), equating to a 3.4 g·h-1 (95%CI: 1.6 to 5.1 g·h-1) greater repletion rate with sucrose vs glucose ingestion. Conclusion: Sucrose ingestion (1.5 g·kg-1·h-1) further accelerates post-exercise liver, but not muscle glycogen repletion when compared to glucose ingestion in trained athletes.
- 13C magnetic resonance spectroscopy
- endurance exercise
- Copyright © 2015, Journal of Applied Physiology