The beneficial effects of exercise, including reduction of cardiovascular risk, are especially important in children with type 1 diabetes (T1DM), in whom incidence of lifetime cardiovascular complications remains elevated despite good glycemic control. Being able to exercise safely is therefore a paramount concern. Dysregulated metabolism in T1DM however, causes frequent occurrence of both hypo- and hyperglycemia, the former typically associated with prolonged, moderate exercise, the latter with higher intensity, if shorter, challenges. While very few absolute contraindications to exercising exist in these children, exercise should not be started with glycemia outside the 80–250 mg/dl range. Within this glycemic range, careful adjustments in insulin administration (reduction or infusion rate via insulin pumps, or overall reduction of dosage of multiple injections) should be combined with carbohydrate ingestion before/during exercise, based on prior, individual experience with specific exercise formats. Unfamiliar exercise should always be tackled with exceeding caution, based on known responses to other exercise formats. Finally, gaining a deep understanding of other complex exercise responses, such as the modulation of inflammatory status, which is a major determinant of the cardio-protective effects of exercise, can help determine which exercise formats and which individual metabolic conditions can lead to maximally beneficial health effects.
Brian D. Tran and Pietro Galassetti
Brian D. Tran, Szu-Yun Leu, Stacy Oliver, Scott Graf, Diana Vigil, and Pietro Galassetti
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 30min of intermittent (2min on, 1min 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.