Ingestion of starch-rich meals after exercise increases glucose kinetics but fails to enhance muscle glycogen replenishment in horses.

The research article investigates how the consumption of starch-rich meals after exhaustive exercise impacts glucose kinetics and muscle glycogen recovery in horses. The study found that while such meals resulted in elevated glucose levels and insulin production, and higher overall body glucose kinetics, they did not significantly enhance muscle glycogen replenishment.

Introduction and Objective

The article begins by noting that intense exercise significantly depletes the muscle glycogen concentration in horses. This depletion can have a negative effect on a horse’s athletic performance in subsequent periods of activity. With this in mind, the researchers set out to study the influence of starch-rich meals consumed after intensive exercise on glucose and insulin levels in the body, as well as muscle glycogen recovery.

Methodology

• The researchers designed a randomized, cross-over study with seven horses, all of which had experienced exercise-induced muscle glycogen depletion.
• In the study, the horses were subjected to one of three conditions after exercise: fasting for 8 hours, consuming half of their daily energy requirements in hay, or eating an isocaloric amount of corn 15 minutes and 4 hours after exercise.

Results

The effects of these different conditions on glucose levels, insulin production, body glucose kinetics, and muscle glycogen replenishment were compared.

• The results showed that horses who were fed starch-rich meals after exercise exhibited mild to moderate hyperglycemia (higher glucose levels) and hyperinsulinemia (greater insulin production).
• These horses also showed a tripling of body glucose kinetics compared to horses that were denied food, indicating a generally higher movement or use of glucose throughout the body.
• Despite these differences, however, the consumption of starch-rich meals only marginally increased muscle glycogen recovery.

Conclusion

Based on their findings, the researchers concluded that while feeding status and diet can significantly impact glucose availability and physiology after intense exercise, they only mildly affect muscle glycogen concentrations—despite the marked differences in soluble carbohydrate ingestion and glucose availability to the skeletal muscle.