Childhood Obesity and the Exercise-induced Inflammatory Response

Abstract

Exercise in normal children causes increases in many immune marker (Nemet et al. Pediatr. 2002), but little is know about the influence of acute exercise on the immune response of obese children. However, research in adults suggested that obesity blunts the exercise response (Kovisto VA, et al. Metab. 1980). PURPOSE: This study determined the influence of childhood obesity on the inflammatory response to exercise. METHODS: The participants were 38, 6–17 yr old boys (n=19) and girls (n=19); divided into normal weight (NW: BMI percentile <85th; n=16) and overweight (OW: BMI percentile >85th; n=22) group. Each completed 10, 2-min bouts of exercise at 75% of maximal power output, each bout separated by 1 -min of rest. Complete blood counts were obtained by standard clinical hematology methods, lymphocyte subset used monoclonal antibodies (mABs), and IL-1β, Il- 1RA, IL-6 and TNFα were analyzed using high sensitivity ELISA kits. RESULTS: The NW and OW groups exercised at the same power output and heart rates. All subsets of leukocyte significantly increased with exercise for both groups (p <0.05), but returned to baseline two hours post exercise. Post-exercise B, T, and N-K cells increased more in the NW than the OW group (p <0.05). Exercise increased Il-6 and TNFα in the NW than the OW group (p=0.0006; p=0.037, respectively). IL-1RA and IL-1β decreased in the NW group, but increased in the OW group (p=0.0001). Exercise-induced changes in total B cells, T cells, and Il-6 were significantly correlated to body fat. The results suggest that overweight children have the same leukocyte response to exercise as normal weight children; but, overweigh youth have diminished IL-6 and enhanced IL-1 responses compared to normal weight youth. CONCLUSIONS: The differing cytokine response appears to be related to body fat content, total lean body mass, circulating lactate and exercise intensity.