title: Evolution of fat oxidation during exercise in obese pubertal boys: clinical implications.
abstract: In this study, we examined fat oxidation rates during exercise in obese pubescent boys. Three groups of pubescent boys (16 pre-pubescent, Tanner's stage I; 16 pubescent, Tanner's stage III; and 14 post-pubescent, Tanner's stage V) performed a graded test on a leg cycle ergometer. The first step of the test was fixed at 30 W and power was gradually increased by 20 W every 3.5 min. Oxygen consumption (VO(2)) and carbon dioxide production (VCO(2)) were determined as the means of measurements during the last 30 s of each step, which allowed us to calculate fat oxidation rates versus exercise intensity. Between 20 and 50% of peak oxygen consumption (VO(2peak)), fat oxidation rate in relative values (mg . min(-1) . kg FFM(-1)) decreased continuously with pubertal development. In the same way, the maximum rate of fat oxidation occurred at a lower percentage of VO(2peak) (pre-pubescent: 49.47 +/- 1.62%; pubescent: 47.43 +/- 1.26%; post-pubescent: 45.00 +/- 0.97%). Our results confirm that puberty is responsible for a decrease in fat free mass capacities to use fat during exercise. The results suggest that post-pubescent obese boys need to practise physical activity at a lower intensity than pre-pubescent boys to enhance lipolysis and diminish adipose tissue and the consequences of obesity.
authors.affiliation: Laboratoire Recherche Littorale en Activites Corporelles et Sportives, Universite du Littoral Cote d'Opale, Dunkerque, France. gautier.zunquin@hotmail.fr
authors.forename: Gautier
authors.initials: G
authors.lastname: Zunquin
authors.forename: Denis
authors.initials: D
authors.lastname: Theunynck
authors.forename: Bruno
authors.initials: B
authors.lastname: Sesboue
authors.forename: Pierre
authors.initials: P
authors.lastname: Arhan
authors.forename: Dominique
authors.initials: D
authors.lastname: Bougle
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D002245:Carbon Dioxide / Q000378:metabolism; D002648:Child; D015444:Exercise / Q000502:physiology*; D005602:France; D006801:Humans; D008297:Male; D009765:Obesity; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology
chemical_list: D002245:Carbon Dioxide