Lipid-Lipoproteins in children: an exercise dose-response study

Purpose: To study the effect of exercise volume on pre- and early-pubertal children's lipid-lipoprotein profile. Methods: Thirty-four children (15 girls) completed 12 wk of exercise training, preceded by a 12-wk control period. Sixteen (7 girls and 9 boys) expended an additional 422 +/- 5 kJ[middle dot]kg-1 BM (LOW, 100 kcal[middle dot]kg-1), whereas 18 (8 girls and 10 boys) expended an additional 586 +/- 7 kJ[middle dot]kg-1 (MOD, 140 kcal[middle dot]kg-1) as a result of the training program. They all exercised on three nonconsecutive days per week at 80 +/- 1% HRpeak. Exercise duration was individualized to match energy expenditure targets. Plasma TG, TC, and HDL-C were measured precontrol, pretraining, and posttraining. LDL-C, TC/HDL-C, and LDL-C/HDL-C were also calculated. Results: Group mean lipid-lipoprotein concentrations did not change as a result of training energy expenditure in either of the groups (P > 0.05). Dietary composition, habitual physical activity, and body composition were also relatively stable over the intervention period (P > 0.05). In the LOW, but not the MOD group, peak [latin capital V with dot above]O2 (mL[middle dot]kg-0.43[middle dot]min-1) tended to increase over the intervention period (P = 0.07). Pearson's product moment correlation analyses indicated that pretraining concentrations of TG, TC, LDL-C, TC/HDL-C, and LDL-C/HDL-C were all related to the small changes seen in the lipid-lipoprotein profile (P < 0.01). Conclusion: Additional energy expenditure of 422 or 586 kJ[middle dot]kg-1, as a direct result of aerobic exercise training over a 12-wk period, did not cause significant alterations in the lipid-lipoprotein profile in pre- and early-pubertal children. This may indicate that the exercise volume was insufficient, the lipoprotein profiles of the majority of children in this study were classified as "desirable," or more likely a combination of these factors. (C)2004The American College of Sports Medicin