title: Effect of a 1-hour single bout of moderate-intensity exercise on fat oxidation kinetics.
abstract: The present study aimed to examine the effects of a prior 1-hour continuous exercise bout (CONT) at an intensity (Fat(max)) that elicits the maximal fat oxidation (MFO) on the fat oxidation kinetics during a subsequent submaximal incremental test (IncrC). Twenty moderately trained subjects (9 men and 11 women) performed a graded test on a treadmill (Incr), with 3-minute stages and 1-km.h(-1) increments. Fat oxidation was measured using indirect calorimetry and plotted as a function of exercise intensity. A mathematical model (SIN) including 3 independent variables (dilatation, symmetry, and translation) was used to characterize the shape of fat oxidation kinetics and to determine Fat(max) and MFO. On a second visit, the subjects performed CONT at Fat(max) followed by IncrC. After CONT performed at 57% +/- 3% (means +/- SE) maximal oxygen uptake (Vo(2max)), the respiratory exchange ratio during IncrC was lower at every stage compared with Incr (P < .05). Fat(max) (56.4% +/- 2.3% vs 51.5% +/- 2.4% Vo(2max), P = .013), MFO (0.50 +/- 0.03 vs 0.40 +/- 0.03 g.min(-1), P < .001), and fat oxidation rates from 35% to 70% Vo(2max) (P < .05) were significantly greater during IncrC compared with Incr. However, dilatation and translation were not significantly different (P > .05), whereas symmetry tended to be greater in IncrC (P = .096). This study showed that the prior 1-hour continuous moderate-intensity exercise bout increased Fat(max), MFO, and fat oxidation rates over a wide range of intensities during the postexercise incremental test. Moreover, the shape of the postexercise fat oxidation kinetics tended to have a rightward asymmetry.
authors.affiliation: Institute of Sport Sciences and Physical Education, University of Lausanne, 1015 Lausanne, Switzerland. xavier.cheneviere@unil.ch
authors.forename: Xavier
authors.initials: X
authors.lastname: Chenevière
authors.forename: Fabio
authors.initials: F
authors.lastname: Borrani
authors.forename: Vincent
authors.initials: V
authors.lastname: Ebenegger
authors.forename: Boris
authors.initials: B
authors.lastname: Gojanovic
authors.forename: Davide
authors.initials: D
authors.lastname: Malatesta
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect; D050260:Carbohydrate Metabolism / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007700:Kinetics; D050356:Lipid Metabolism / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology; D014664:Vasodilation / Q000502:physiology; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide; D006899:Mixed Function Oxygenases