Effect of postexercise carbohydrate supplementation on muscle glycogen repletion in trained sled dogs

Abstract

Objective - To evaluate the effect of immediate postexercise carbohydrate supplementation on muscle glycogen (MG) repletion during the first 4 hours of recovery in sled dogs. Animals - 24 Alaskan Huskies. Procedure - Dogs were assigned to 1 of 3 treatment groups, and a muscle biopsy specimen was obtained 1 hour before and immediately (group A) or 4 hours (groups B and C) after a 30-km run. Immediately after exercise, dogs in group A and group C were given water; dogs in group B were given a glucose polymer solution (1.5 g/kg of body weight) in water. Results - At 4 hours after exercise, MG concentration was significantly greater in group-B than in group-C dogs; the value in group-C dogs was not different from the value in group-A dogs immediately after exercise. Assuming similar rates of glycogen depletion between treatment groups, during the first 4 hours of recovery, group-B dogs replaced 49% of the glycogen used during exercise. Plasma glucose concentration was significantly greater in group-B than in group-A and group-C dogs at 100 minutes after exercise. Conclusions - Immediate postexercise carbohydrate supplementation in sled dogs leads to increased glucose concentration, which in turn promotes more rapid rate of MG repletion in the first 4 hours of recovery than is observed in dogs not given supplements. Clinical Relevance - For dogs running in multiple heats on a single day or over several consecutive days, immediate postexercise carbohydrate supplementation may promote more rapid and complete recovery between bouts of exercise.