Comparison of fat oxidation during exercise in lean and obese pubertal boys: clinical implications.
OBJECTIVE
To examine fat oxidation rates during exercise in lean and obese pubescent children.


METHODS
A graded leg cycle ergometry test was performed by two groups of pubescent boys (13 lean: mean (SD) age 12.0 (0.5) years, body mass index (BMI) 18.56 (1.12) kg/m(2); 17 obese: mean (SD) age 12.1 (0.1) years, BMI 26.68 (3.37) kg/m(2); p<0.001). The first step of the test was fixed at 30 W and power was gradually increased by 20 W every 3.5 min. The mean ventilatory gas measurement was obtained during the last 30 s of each step for calculation of fat oxidation rate vs exercise intensity.


RESULTS
At low intensity (0-30% of peak oxygen consumption) when fat-free mass is considered, the fat oxidation rate was identical for the two groups. At higher intensities (40%, 50% and 60% of peak oxygen consumption) the fat oxidation rate was significantly higher in lean boys than in obese boys.


CONCLUSIONS
These results confirm that obese pubertal boys have fat-free mass decreased capacities to use fat during moderate exercise. The findings suggest that obese boys need to practise physical activity at a lower intensity than healthy boys to enhance lipolysis and diminish adipose tissue and the consequences of obesity.
Zunquin
G
G
Laboratoire REcherche Littorale en Activités Corporelles et Sportives, Dunkerque, Université du Littoral Côte d'Opale, F 59140, Dunkerque, France. gautier.zunquin@hotmail.fr
Theunynck
D
D
Sesboüé
B
B
Arhan
P
P
Bouglé
D
D
D000273:Adipose Tissue / Q000378:metabolism*; D015992:Body Mass Index; D002151:Calorimetry; D002648:Child; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology; D013851:Thinness / Q000378:metabolism*