title: Interaction of diet and training on endurance performance in rats.
abstract: We determined the interaction of diet and training on metabolic adaptations in skeletal muscle and liver, and the consequences of these adaptations for endurance. Eighty rats performed a baseline treadmill run to exhaustion at 16 m min(-1) (RUN1) and were then divided into two groups and given one of two diets: high carbohydrate (CHO) or high fat (FAT). Each dietary group was then divided into one of four subgroups: sedentary control that performed no training (NT); low-intensity running (8 m min(-1); LOW) and two groups who trained at their maximal voluntary running speed without electrical stimulation (28 m min(-1); VMAX). Training volume was identical for LOW and VMAX (1000 m session(-1)) and animals ran 4 days week(-1) for 8 weeks. To assess the interaction of the higher intensity exercise with diet, a second endurance test (RUN2) was undertaken after 6 weeks at either 16 m min(-1) or 28 m min(-1). The NT group ran for a longer duration (increase of 77 %) after FAT than CHO (239 +/- 28 vs. 135 +/- 30 min, P < 0.05) at 16 m min(-1). There were no differences in RUN2 for the LOW group when rats ran at 16 m min(-1) (454 +/- 86 vs. 427 +/- 75 min for CHO and FAT groups, respectively), but rats in the VMAX group fed FAT ran longer than rats fed CHO at 28 m min(-1) (100 +/- 28 vs. 58 +/- 11 min, respectively, P < 0.05). FAT increased the activities of the enzymes citrate synthase, beta-hydroxyacyl-CoA dehydrogenase and carnitine palmitoyl-transferase compared to CHO (P < 0.01), but there was no systematic effect of training. We conclude: (1) there was no additive effect of a high-fat diet on endurance performance when rats performed low-intensity training; (2) running performance at 28 m min(-1) was only enhanced by a high-fat diet after more intense training; (3) diet-induced and training-induced adaptations that increase exercise capacity may be under independent control. Experimental Physiology (2001) 86.4, 499-508.
authors.affiliation: Exercise Metabolism Group, School of Medical Sciences, RMIT University, Bundoora 3083, Victoria, Australia.
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: C R
authors.initials: CR
authors.lastname: Bruce
authors.forename: L L
authors.initials: LL
authors.lastname: Spriet
authors.forename: J A
authors.initials: JA
authors.lastname: Hawley
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000818:Animals; D001786:Blood Glucose; D015992:Body Mass Index; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004032:Diet; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004041:Dietary Fats / Q000494:pharmacology*; D004326:Drinking / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D006003:Glycogen / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D006003:Glycogen; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002334:Carnitine O-Palmitoyltransferase; D002950:Citrate (si)-Synthase