title: Participation in a 1,000-mile race increases the oxidation of carbohydrate in Alaskan sled dogs.
abstract: The Alaskan Husky has been specifically bred for endurance performance and is capable of extreme endurance performance. We examined sled dogs in the trained state at the beginning of the race season and after a 1,600-km race (Iditarod). Our hypothesis was that lipids would be the predominant substrate during submaximal exercise in long-distance racing sled dogs, and a 1,600-km race would increase the reliance on lipids during an exercise bout at the same absolute exercise intensity. The experiments were completed over three testing periods, which were completed in January of two different years before participation in a 1,600-km race, or in March shortly after completion of a 1,600-km race. After determination of H(13)CO3 (-) recovery, the dogs were tested with primed continuous infusions of [1,1,2,3,3-(2)H]glycerol, [3-(13)C]lactate, or [6,6-(2)H2]glucose. During exercise, respiratory exchange ratio was significantly higher in raced (0.92 ± 0.01) compared with nonraced (0.87 ± 0.01) dogs. During exercise, glucose rate of appearance was potentially sustained by a large glycerol rate of disappearance with an increase in lactate rates of oxidation after a 1,600-km race. Therefore, contrary to our hypothesis, the sled dogs were dependent on carbohydrate energy sources, a reliance that increased further after participation in a 1,600-km race.
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; Benjamin.F.Miller@ColoState.edu.
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Miller
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Drake
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Frederick F
authors.initials: FF
authors.lastname: Peelor
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Laurie M
authors.initials: LM
authors.lastname: Biela
authors.affiliation: Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan;
authors.forename: Raymond
authors.initials: R
authors.lastname: Geor
authors.affiliation: Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria, Australia; and.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hinchcliff
authors.affiliation: Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma.
authors.forename: Michael
authors.initials: M
authors.lastname: Davis
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Karyn L
authors.initials: KL
authors.lastname: Hamilton
mesh_terms: D000465:Algorithms; D015308:Anaerobic Threshold / Q000502:physiology; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000502:physiology*; D004285:Dogs; D005260:Female; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D007700:Kinetics; D019344:Lactic Acid / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology; D008297:Male; D010084:Oxidation-Reduction; D010805:Physical Conditioning, Animal; D010807:Physical Endurance / Q000502:physiology; D012420:Running / Q000502:physiology*
chemical_list: D001639:Bicarbonates; D019344:Lactic Acid; D005947:Glucose; D005990:Glycerol
keywords: canine; carbohydrate; exercise; stable isotope; substrate