Altered insulin response to an acute bout of exercise in pediatric obesity

Pediatric obesity typically induces insulin resistance, often later evolving into type 2 diabetes. While exercise, enhancing insulin sensitivity, is broadly used to prevent this transition, it is unknown whether alterations in the exercise insulin response pattern occur in obese children. Therefore, we measured exercise insulin responses in 57 healthy weight (NW), 20 overweight (OW), and 56 obese (Ob) children. Blood samples were drawn before and after 30 min of intermittent (2 min on, 1 min off) cycling at ~80% VO2max. In a smaller group (14 NW, 6 OW, 15 Ob), a high-fat meal was ingested 45 min preexercise. Baseline glycemia was similar and increased slightly and similarly in all groups during exercise. Basal insulin (pmol/L) was significantly higher in Ob vs. other groups; postexercise, insulin increased in NW (+7± 3) and OW (+5 ± 8), but decreased in Ob (-15±5, p < .0167 vs. NW). This insulin drop in Ob was disproportionately more pronounced in the half of Ob children with higher basal insulin (Ob-H). In all groups, high-fat feeding caused a rapid rise in insulin, promptly corrected by exercise. In Ob, however, insulin rose again 30 min postexercise. Our data indicates a distinct pattern of exercise-induced insulin modulation in pediatric obesity, possibly modulated by basal insulin concentrations.