Evolution of fat oxidation during exercise in obese pubertal boys: Clinical implications |
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| Authors: | Gautier Zunquin Denis Theunynck Bruno Sesboüé Pierre Arhan Dominique Bouglé |
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| Institution: | 1. Laboratoire Recherche Littorale en Activités Corporelles et Sportives, Université du Littoral C?te d'Opale , Dunkerquegautier.zunquin@hotmail.fr;3. Laboratoire Recherche Littorale en Activités Corporelles et Sportives, Université du Littoral C?te d'Opale , Dunkerque;4. Service Explorations Fonctionnelles;5. Laboratoire de Physiologie Digestive et Nutritionnelle;6. Service de Pediatrie A, CHU de Caen , Caen, France |
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| Abstract: | 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 (Vdot]O2) and carbon dioxide production (Vdot]CO2) 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 (Vdot]O2peak), 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 Vdot]O2peak (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. |
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| Keywords: | Childhood obesity substrate oxidation exercise puberty |
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