Effect of multiday exercise on serum hormones and metabolic substrate concentrations in racing sled dogs

Abstract

Prolonged submaximal exercise relies on the steady delivery of oxidizable substrates to the working muscle, with the sources of those substrates either stored reserves or food absorbed from the gastrointestinal tract during exercise. Fat oxidation could be advantageous for this type of exercise because of potentially greater reserves, but recent studies suggest that athletic dogs remain highly dependent on carbohydrate to fuel exercise despite ingesting a high fat diet. The purpose of this study was to characterise the pattern of exercise-induced hormone and substrate concentrations as they relate to carbohydrate and fat metabolism during prolonged submaximal exercise in dogs. Two studies (a..