Riddell, M. C., Timmons, B. W., & Bar-Or, O. (2005). Exogenous carbohydrate oxidation during exercise in boys: Influence of age and puberty. Medicine and Science in Sports and Exercise, 37(5), Supplement abstract 1618.

Twelve years-old (N = 19) and fourteen years-old (N = 13) boys were grouped according to pubertal age. Ss cycled for 60 minutes at 70% VO2max while intermittently drinking a carbohydrate solution (4% sucrose, 2% glucose solution of ~1.5 g/kg). Respiratory exchange ratio and CHO oxidation were analyzed in the last 15 minutes of the exercise.

Younger boys tended to have a lower respiratory exchange ratio than the older boys. Young boys also tended to have a higher % of energy contribution from CHO. Oxidation efficiency of CHO was similar between groups.

Implication. Puberty is an important determinant of fuel selection during high-intensity exercise in pre- and early-pubertal boys. CHO intake may be beneficial for performance in this age-group.

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